Bart Wolbers
Bart Wolbers
- 31 min read

660nm Wavelength Health Effects Cheatsheet

This blog post breaks down all the 660nm health effects, into human, animal, and in vitro (cell culture) studies. You'll also learn where the evidence level is solid or not.

660nm Wavelength Health Effects Cheatsheet
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Introduction

In this blog post, I talk about the 660nm wavelength health effects or 660nm health benefits. As you may know, 660nm is red light.

Many people ask me on a weekly basis what each red light therapy wavelength really does. The answer isn't simple because there are often hundreds of studies on each wavelength.

For 660nm, there are more than 900+ studies in Vladimir Heiskanen's Excel sheet. Below I've created an easier way to see the pattern in these studies.

💡
Vladimir Heiskanen is an independent researcher in the red light therapy space. He's created an Excel sheet with almost all red light therapy studies (more aptly "photobiomodulation studies" that have been published. That Excel sheet is regularly updated. I couldn't have created this 660nm cheatsheet without Vladimir's support as the project would have taken me a lot more time. So, a loving thanks to Vladimir!

As I will argue later on in this blog post, however, my approach is far from perfect. I'll explain all the complications in a later "advanced comments" section - if you wish to do so, you can select that section in the table of contents on the left of your screen.

Also, below I've added a summary that explains the basics of the 660nm effects. Below that I've listed all studies in their categories, with links to all studies.

If you really want to understand a topic, you'll have to read the studies, not just trust my categorization. However, because all studies have been collected together in this way, a full understanding is much easier in many cases.

So, for the best results, don't take me on my word but do your own thinking and research! Next up, let's consider all the 660nm health effects:

660nm Health Effects Summary

As stated before, I've divided the 660nm health effects into

  1. human studies
  2. animal studies
  3. in vitro studies

And given preference to human studies over animal studies, and animal over in vitro/ex vivo studies. So let's begin:

656-665nm Human Evidence Outcomes

Strong Evidence For Health Benefits: 3+ Human Studies With 65%+ Positive Outcomes:

  • Stroke recovery - so a clinical situation where the stroke already happened.
  • Dermatology conditions, such as acne vulgaris, herpes labialis.
  • Dermatology, skin rejuvenation.
  • Eye health - for Age-Related Macular Degeneration (AMD).
  • Hair loss - specifically the "Androgenetic Alopecia" condition that's the most common type of hair loss
  • COVID-19 recovery
  • Joint health, specifically for dealing with osteoarthritis.
  • Oral health, with many domains affected, such as oral hypesensitivity and helping you deal with the aphthous stomatitis, dry mouth, burning mouth syndrome, graft-versus-host disease, lichen planus, oral mucositis, osteonecrosis, TMD, and overall health support with tooth extraction.
  • Allergic rhinitis of the nose
  • Sleep quality
  • Cardiac surgery
  • Different types of wound healing, which are that of a diabetic foot ulcer, a pressure ulcer, and venous ulcer.

Some Evidence: 1-2 Human Studies Either 100% Positive Or 50-50% Positive/Neutral

  • This some evidence for human health benefits category contains 74 different benefits that have to be confirmed with more research but are very promising already. Once more positive human studies are available, the studies found in this category would move to the strong human evidence category. If new negative or neutral studies are found, they would move to the neutral/insufficient/conflicting evidence category.

Insufficient Or Neutral Or Conflicting Evidence - Therefore, Not To Be Included In The Other Categories Of Human Evidence

  • In this category, you'll find 34 different outcomes where the evidence is unclear whether there's an effect. For instance, there may be several positive and negative studies on the same topic that contradict each other.

Strong Evidence For Health Harm: 3+ Human Studies With 65%+ Negative Outcomes

  • Hearing, tinnitus
  • Exercise, for running
  • In this category, we find three outcomes with 3+ studies whereby 65% show negative health harm or a neutral outcome in some cases. If you want to know why the studies are negative then you'll have to read the studies. I'm very explicit about people reading these studies and not me commenting on it because I'll get far too many questions and have to spend far too much time on giving feedback to people if you're not reading the studies yourself. So, as always, if you want to know why an outcome is negative or neural or positive, use your own brain. I'm not saying this to be an asshole, I'm just preventing having to reply to hundreds of emails and questions on this topic that I don't have the resources for. I wish I could...

656-665nm Animal Study Evidence Outcomes

Strong Animal Study Evidence: 3+ Animal Studies Available And 65%+ Positive

  • Bone repair
  • Brain, stroke prevention
  • Blood circulation, both for the creation of new blood vessels (angiogenesis) and countering hypertension.
  • Edema of the paw in animals (veterinary medicine).
  • Heart health, specifically after mycardial infarction.
  • Joints, countering arthritis.
  • Ligaments, a MCL ligament injury in the knee (Medial Collateral Ligament).
  • Muscle injuries.
  • Nervous system, specifically a sciatic nerve injury in the lower back and the spinal cord.
  • Oncology, for tumor cells. If you want to know the specific effects, again, please read the studies!
  • Oral health, periodontium.
  • Pain, hyperalgesia (excess pain to stimuli or the absence thereof that shouldn't hurt) and neurpathic pain
  • Repiratory system, for asthma and lung inflammation
  • Surgery, skin flaps and graft integration
  • Snake venom toxins protection
  • Wound healing, preventing diabetic wounds and wound healing after an excision.

Insufficient Or Neutral Or Conflicting Animal-Based Evidence:

  • Here 76 different effects can be found that are currently unproven or neutral or have conflicting evidence. These results are far too many to summarize in this small section.

Animal-Based Evidence For Health Harm: 3+ Studies With 65% Or More Negative Outcomes

  • None, which may imply publications bias. Or the way Vladimir Heiskanen uses his green/yellow/red categorization method in the Excel sheet.

In Vitro And Ex Vivo Studies

Strong In Vitro Evidence With 3+ Studies And 65%+ Positive:

  • Cells, different aspects, such as proliferation, energy production, fibroblast function, and a scratch-wound model.
  • Gene expression of fibroblasts.
  • Oral, dentin health and the periodontium
  • Stem cells, different types such as those from the bone marrow or from fat stores.

Insufficient Exclusive In Vitro Evidence (Not Included In Categories Above Or Below)

  • 59 different outcomes are found here, all that need more research or that have conflicting outcomes.

Strong Exclusive In Vitro Evidence With 3+ Studies And 65%+ Negative, Implying Health Harm:

  • No studies found in this category, once again.

The 656nm-665nm (Mostly 660nm) Wavelengths Health Effects:

Here's the full breakdown of almost 1,000 studies on all wavelengths around 660, so 656 to 665nm light.

656-865nm Human Evidence Outcomes (Mostly The 660nm Wavelength)

In the next section you'll find human studies on 660nm. As you may know, studies on humans carry the highest level of evidence. Both positive and negative outcomes are included.

If you want to know why an outcome is positive or negative, you'll have to click the numbers to read the studies.

Here we go:

Strong Evidence For Health Benefits: 3+ Human Studies With 65%+ Positive Outcomes

Brain, Stroke (Clinical) - (39, 630+660+850, human, positive), (40, 660+808+980, human, positive), (41, 660+850, human, positive).

Dermatology, Acne Vulgaris - (116, 660 vs 830, human RCT, positive), (117, 420+660, human RCT, positive), (118, 415 vs 415+660 vs white, human RCT, positive).

Dermatology, Herpes Labialis - (123, 660, human, positive), (124, 660, human, positive), (125, 660, human, positive), (126, 660, human, positive), (127, 660, human, positive).

Dermatology, Skin Rejuvenation - (136, 590+660, human, positive), (137, 440+660+780, human RCT, positive), (138, 660+850, human, positive), (139, 660, in vitro, positive), (140, 660 vs 411-777, human RCT, positive), (141, 660, human, positive), (904, 658, human RCT, negative).

Eyes, Age-Related Macular Degeneration - (158, 590+660+850, human, positive), (159, 590+660+850, human RCT, positive), (160, 660, in vitro, positive), (161, 590+660+850, human RCT, positive).

Hair, Androgenetic Alopecia - (179, 660+808, human RCT, positive), (180, 660, human, positive), (181, 660, human, negative), (182, 650+660, human RCT, positive), (183, 630+650+660, human RCT, positive), (901, 665 vs 665+808, human RCT, positive).

Infections, COVID-19 - (215, 660, animal, positive), (216, 660 vs 660+808, human, positive), (217, 660, human, positive), (218, 660, human RCT, positive), (219, 660, human, neutral), (220, 660, human, positive), (221, 630+660, human, positive), (222, 660, human, positive).

Joints, Osteoarthritis - (229, 660+808, human RCT, positive), (906, 658+810, human RCT, positive), (907, 405+658+810, human, neutral).

Nervous System, Diabetic Neuropathy - (305, 633+660+850, human, positive), (306, 660, human RCT, positive), (307, 633+660+850, human, positive), (308, 660, animal, positive), (309, 633+660+850, human, positive).

Oral, Aphthous Stomatitis - (372, 660, human RCT, positive), (373, 660 vs 10600, human RCT, negative), (373, 660, human RCT, positive), (374, 660, in vitro, neutral), (375, 660, human, positive), (912, 658, human RCT, positive).

Oral, Burning Mouth Syndrome - (381, 660-970, human RCT, positive), (382, 660, human RCT, positive), (383, 660, human, positive), (384, 660, human, positive).

Oral, Dentin Hypersensitivity - (400, 660+1064+1340, human, positive), (401, 660+810, human RCT, positive), (402, 660+808, animal, positive), (403, 660, human RCT, positive), (404, 660, human RCT, positive), (405, 660, in vitro, positive), (406, 660, human RCT, positive), (407, 630 vs 660, human RCT, positive), (408, 660, human RCT, neutral), (409, 660+830, human, positive), (410, 660, human, positive).

Oral, Dry Mouth (Xerostomia / Hyposalivation) - (411, 660+808, human, positive), (412, 660+810, human RCT, negative), (413, 660+780, human, positive), (414, 660+780, human, positive), (415, 660, human, positive).

Oral, Graft-Versus-Host Disease - (450, 660, human, positive), (451, 660, human, positive), (452, 660, human, positive), (453, 660+810+850, human, positive), (454, 660 vs 660+850, human, positive).

Oral, Lichen Planus - (457, 660, human RCT, negative), (458, 660, human RCT, positive), (459, 660, human RCT, positive), (460, 660, human RCT, positive).

Oral, Oral Mucositis - (474, 660, human, positive), (475, 660, human RCT, negative), (476, 660, animal, positive), (477, 660+780, animal, positive), (478, 660+780, animal, positive), (479, 660 vs 810 vs 660+810, human RCT, positive), (480, 660, animal, positive), (481, 468 vs 660, human, positive), (482, 660+850, human RCT, positive), (483, 660+810+980, human RCT, positive), (484, 660, human, neutral), (485, 660, human RCT, positive), (486, 660, human, positive), (487, 660, human RCT, positive), (488, 660, human RCT, neutral), (489, 660, human, positive), (490, 660, human RCT, positive), (491, 660, human, positive), (492, 660, human, positive), (493, 660, human, neutral), (494, 660, human RCT, neutral), (495, 660, human, positive), (496, 660, human, positive), (497, 660 vs 810+980, animal, positive), (498, 660, human, positive), (499, 970 vs 660+800+970, human+in vitro, positive), (500, 660+808, human, positive), (501, 660+808, human RCT, positive), (502, 660+808, human RCT, positive), (503, 660, human RCT, positive), (504, 660+970, human RCT, positive), (505, 660, human, positive), (506, 660, human, positive), (507, 660, human, positive), (508, 660, human RCT, positive), (509, 660, human, positive), (510, 660, human, positive), (511, 660, human RCT, positive), (512, 660, animal, positive), (513, 660+ 808, human, positive), (514, 660+850, human, positive), (515, 660, human, positive), (516, 660, human, positive), (517, 635+808+660, animal, positive), (518, 660, human RCT, positive), (519, 660 vs 810 vs 980 vs 1064, animal, positive), (520, 660, human RCT, positive), (521, 660, human RCT, positive), (522, 660, human RCT, positive), (523, 660, human, positive), (524, 660, animal, positive), (525, 630 vs 660, human, positive), (526, 660 vs 810 vs 980 vs 1064, animal, positive), (527, 660+670, animal, positive), (528, 660, animal, positive), (529, 660+760, human, positive), (530, 660 vs 830, human, positive), (531, 660, human RCT, positive), (532, 660, human RCT, negative), (533, 660, haman RCT, positive), (534, 660, human RCT, positive), (535, 660, human positive), (536, 660+780, human, positive), (537, 660, human, positive), (538, 660, animal, neutral), (539, 660+808, human, neutral), (540, 660, animal, neutral), (541, 660+
780, human, positive), (542, 660, animal, positive), (543, 660, human, positive), (543, 660, human, positive), (544, 660, human, positive), (545, 660, human, positive), (546, 660, human RCT, positive), (914, 658, human RCT, negative).

Oral, Osteonecrosis - (563, 660, animal, positive), (564, 660+808, human, positive), (565, 660, human positive), (566, 660+808, human, positive), (567, 660+808, human, positive), (568, 660+808, human, positive), (569, 660, animal, positive), (570, 660, human, positive).

Oral, TMD - (613, 660, human RCT, negative), (614, 660+808, human RCT, positive), (615, 660+850, human RCT, positive), (616, 660+808, human, positive), (617, 660, human RCT, positive), (618, 660, human RCT, positive), (619, 660 vs 795, human RCT, positive), (620, 660 vs 780 vs 790 vs 830, human, neutral).

Oral, Tooth Extraction - (622, 660+830, animal, positive), (623, 660, human, negative), (624, 660+810, human RCT, positive), (625, 660, human RCT, positive), (626, 660, human RCT, positive), (627, 660+808, human RCT, neutral), (628, 660, human, positive), (629, 660+810, human RCT, positive), (630, 660 vs 808, animal, positive), (631, 660 vs 810 vs 660+810, human RCT, positive), (632, 660, human RCT, positive), (633, 660, human RCT, positive), (634, 660, human RCT, negative), (635, 660+808, human RCT, negative), (636, 660+810, human RCT, positive), (637, 660, human, positive), (638, 660, human RCT, neutral).

Respiratory System, Allergic Rhinitis - (688, 660+940, human, positive), (689, 660, animal, positive), (690, 660, human RCT, neutral), (691, 660, human, positive), (692, 660, human RCT, positive), (916, 658, animal, positive).

Sleep Medicine, Sleep Quality - (717, 660+740+810+870, human RCT, neutral), (718, 660+850, human, neutral), (917, 658, human RCT, positive).

Surgery, Cardiac Surgery - (740, 660, human RCT, positive), (741, 660, human RCT, positive), (742, 660, human RCT, positive), (743, 640+660, human RCT, positive), (744, 640+660, human RCT, positive), (745, 660, human RCT, positive), (748, 660+950, human, positive).

Wound Healing, Diabetic Foot Ulcer - (833, 660, human, negative), (834, 660+800+970, human, positive), (835, 632+660+850, human, positive), (836, 625+660+850 vs 580-900, human, neutral), (837, 660, human RCT, positive), (838, 660, human RCT, positive), (839, 250+660+820+880, human, positive), (840, 660+890, human RCT, positive), (841, 660+890, human, positive), (922, 648, human RCT, positive).

Wound Healing, Pressure Ulcer - (887, 660, human, positive), (889, 660+820+870+880+940+950, human RCT, neutral), (923, 658 vs 808 vs 940, positive, human RCT), (924, 658 vs 808 vs 940, human RCT, positive)

Wound Healing, Venous Ulcer - (890, 660+880, human RCT, positive), (891, 660+950, human RCT, neutral), (892, 660+880, human RCT, positive), (893, 660+880, human, positive).

Some Evidence: 1-2 Human Studies Either 100% Positive Or 50-50% Positive/Neutral

Brain, Depression - (34, 660+850, human, positive).

Brain, Parkinson's Disease - (38, 660+670+810+850, human, positive).

Circulation, Microcirculation - (109, 660+850, human, positive), (110, 625+
660+850, human RCT, positive).

Circulation, Serum Inflammatory Markers - (113, 660, human, positive).

Dermatology, Fixed Drug Eruption (FDE) - (122, 660, human, positive).

Dermatology, Radiation Dermatitis - (129, 660 vs 880, animal, positive), (130, 660, animal, positive), (131, 660, human, positive), (132, 660+805, human, positive).

Dermatology, Scars (Clinical) - (133, 660+825+840, human, positive), (134, 660, in vitro, positive).

Dermatology, Skin Inflammation (Due To Skin Perturbation) - (925, 656, human RCT, positive).

Dermatology, UV Skin Damage And Erythema - (142, 660, animal, positive), (143, 660, animal, positive), (144, 660, in vitro, positive), (145, 660, in vitro, positive), (146, 660, human, positive).

Gastroenterology, Colonic Motility Dysfunction - (169, 660+825+840, human, positive).

Hair, Alopecia Areata - (178, 660, human, positive).

Hair, Lichen Planopilaris - (187, 650+660, human, positive).

Infections, COVID-19: Post-Covid Symptoms - (214, 660+850 vs 1070, human, positive).

Joints, Osteoarthritis (Hand) - (907, 658+785, human, positive).

Liver, Fatty Liver - (238, 660, human RCT, positive).

Lymphatic System, Lymphederma - (908, 658, human, positive).

Muscle, Handgrip Strength - (288, 660 vs 830, human RCT, positive).

Muscle, Muscle Weakness - (299, 660 vs 830, human RCT, positive).

Nervous System, CNS: Bell's Palsy - (303, 660+808, human, positive), (304, 660+780, human, positive).

Oncology, HSF / PPED - (335, 660, human RCT, positive).

Oncology, Human Research - (336, 660, human, positive).

Oncology, Supportive Care - (338, 660, human RCT, positive).

Oral, Anesthesia Duration - (370, 660 vs 810, human RCT, positive).

Oral, Anesthesia Injection Pain - (371, 660, human RCT, positive).

Oral, Bleaching - (376, 660-900, human, neutral), (377, 660+808, animal, neutral), (378, 660+810, human RCT, positive).

Oral, Buccal Fat Removal - (380, 660, human, positive).

Oral, Caries - (385, 480-3400, 625+660+850, human RCT, positive), (386, 660, animal, negative).

Oral, Cicatricial Pemphigoid - (387, 660, human, positive).

Oral, COVID-19 / Oral Symptoms - (388, 660+808, human, positive), (389, 660, human, positive).

Oral, Bone Implants: Bone Augmentation - (391, 660+808, human RCT, positive), (392, 630-660, human RCT, positive),

Oral, Dental Implants: Peri-Implant Mucositis - (393, 660 vs 940, human RCT, positive).

Oral, Dental Implants: Postoperative Complications - (394, 660+810, human RCT, positive).

Oral, Dental Implants: Stability - (395, 660, human, neutral), (396, 660+840, human, positive).

Oral, Dysgeusia - (416, 660+808, human RCT, positive).

Oral, Endodontics: Dentin-Pulp Complex - (419, 660, human RCT, positive).

Oral, Endodontics: Hypochlorite Accident - (421, 660, human, positive).

Oral, Endodontics: Root Canal Treatment Success - (428, 660, human RCT, positive).

Oral, Geographic Tongue - (447, 660, human RCT, positive).

Oral, Leukoplakia - (455, 660, human, positive), (456, 660, human RCT, positive).

Oral, Mastication - (461, 660+890, human RCT, positive).

Oral, Mucoleles - (462, 660, human, positive),

Oral, Necrotizing Sialometaplasia - (463, 660, human, positive).

Oral, Nerves: Inferior Alveolar - (464, 660+808, human, positive).

Oral, Nerves: Inferior Alveolar - (465, 660 vs 808, animal, positive), (466, 660+810, human RCT, positive), (467, 660+789, human RCT, positive).

Oral, Oral Mucosal Necrosis - (470, 660, human, positive), (471, 660+850, human, positive).

Oral, Oral Mucosal Ulcer - (472, 660, human, positive), (473, 660+808, animal, negative).

Oral, Oral Surgery: Orthognathic Surgery - (552, 660, human RCT, positive).

Oral, Oral surgery - (553, 660, human RCT, positive).

Oral, Orofacial Granulomatosis - (554, 660, human, positive).

Oral, Orthodontics: Gingival Health - (555, 660, human RCT, positive).

Oral, Orthodontics: Implants / Miniscrews - (556, 660+808, human, positive), (557, 660, human, neutral).

Oral, Orthodontics: Pain - (558, 660+810, human RCT, positive), (559, 640+660, human RCT, neutral).

Oral, Orthodontics: RME / Maxillary Expansion - (560, 660, human RCT, positive).

Oral, Orthodontics: Tooth Movement - (561, 530 vs 660, animal, positive), (562, 660, animal, positive), (915, 658, human RCT, positive).

Oral, Palatal Hemangioma - (571, 660, human, positive).

Oral, Palatal Ulcer - (572, 660, human, positive).

Oral, Pemphigus Vulgaris - (573, 660, human, positive), (574, 660, human, positive).

Oral, Pericoronitis - (575, 660 vs 808 vs 1064, human RCT, positive).

Oral, Periodontium: Gingival Inflammation - (579, 660, human, positive).

Oral, Toxic Epidermal Necrolysis (TEN) - (639, 660, human, positive).

Oral, Trauma / Fractures - (640, 660+850, human RCT, positive), (641, 660, human RCT, positive).

Oral, Ulcers - (642, 660, human, positive).

Oral, Uncategorized (Dental) - (643, 660, human, positive).

Pain, Back Pain - (651, 660, human, positive), (652, 660+850, human RCT, positive).

Pain, Fibromyalgia - (654, 660+850, human RCT, positive), (655, 660+850, human RCT, neutral).

Pain, Knee Pain - (660, 660+850, human RCT, positive).

Reproductive System, Vaginal Mucosa - (686, 415+660+850, human, positive), (896, 662+855, human, positive).

Stevens-Johnson Syndrome - (739, 660, human, positive).

Systemic effects, Metabolic Health - (789, 660, human RCT, positive).

Tendons, Achilles Tendon - (791, 660, animal, positive), (792, 660, animal, positive), (793, 660, animal, positive), (794, 660, animal, positive), (795, 660+830, animal, negative), (796, 660+830, animal, positive), (797, 660, animal, neutral), (798, 660, animal, positive), (799, 660, animal, positive), (800, 660+830+904, human, positive), (918, 658+858+904, human, neutral).

Wound Healing, Abrasion - (810, 660+820+870+880+940+950, human RCT, positive).

Wound Healing, Burns (Clinical) - (811, 650+660+810, human, positive), (812, 660, animal, positive), (813, 660, animal, positive), (814, 660, animal, positive), (815, 660, animal, positive), (816, 660, animal, negative), (817, 660, animal, positive), (818, 632+660+850+904, animal, positive), (819, 660, animal, positive), (820, 660, animal, positive), (821, 660+780, animal, positive), (822, 660, animal, positive), (823, 660, animal, positive), (824, 660, animal, positive), (825, 660, animal, positive), (826, 660 vs 780 vs 400-2000, animal, positive), (827, 660+780, animal, positive), (828, 660+780, animal, positive), (920, 658, human, positive).

Wound Healing, Chronic - (829, 660, animal, positive), (830, 660+950, animal, positive), (831, 660+940, human RCT, positive).

Wound Healing, Diabetic Foot Ulcer: PDT Clinical Studies - (832, 660, human, positive).

Wound Healing, Digital Ulcers (Systemic Sclerosis) - (848, 405+660+850, human, positive).

Insufficient Or Neutral Or Conflicting Evidence - Therefore Not To Be Included In The Other Categories Of Human Evidence

Carpal Tunnel, Carpal Tunnel Syndrome - (45, 660, human RCT, neutral).

Carpal Tunnel, Wrist Pain (Chronic) - (46, 420+660+890, human RCT, neutral).

Circulation, Blood Flow (Feet) - (103, 660, human, negative).

Diabetes Mellitus, Glycemia - (148, 450+520+660+904, human, negative), (148, 660, animal, positive), (149, 660, animal, positive).

Eyes, Reticular Pseudodrusen (RPD) - (164, 590+660+850, human, neutral).

Hair, Hair Follicle Transplantation - (184, 660, human RCT, negative).

Joints, Rheumatoid Arthritis - (232, 660, animal, neutral), (233, 660-
950, human RCT, negative).

Muscle, Exercise: High-Intensity - (264, 660+850, human RCT, negative).

Muscle, Exercise: Resistance Exercise - (265, 660+850, human RCT, negative).

Muscle, Exercise: Swimming - (268, 660+850, human RCT, negative).

Muscle, Exercise: Water Polo - (269, 660+850, human RCT, negative).

Muscle, Exercise - (272, 660+850, human RCT, negative), (273, 660+850, human RCT, positive), (274, 660 vs 904, human RCT, positive), (275, 660+850, human RCT, positive), (276, 660+850, human RCT, neutral), (277, 660+850, human RCT, positive), (278, 660, human RCT, negative), (279, 660 vs 830, human RCT, neutral), (280, 660+850, human RCT, neutral), (280, 660+850, human RCT, neutral), (281, 660+850, human RCT, positive), (282, 810 vs 660+850, human RCT, negative), (283, 660+850, human RCT, positive), (284, 660+850, human RCT, negative), (285, 660+850, human RCT, negative).

Muscle, Muscle Fatigue - (291, 660 vs 808, human RCT, negative).

Nervous System, PNS: Radial Nerve Conduction - (310, 660+880, human RCT, negative).

Oncology, Chemotherapy-Induced Neuropathy - (910, 658, human RCT, neutral).

Oral, Dental Anxiety - (390, 660, human RCT, neutral).

Oral, Endodontics: Postoperative Symptoms - (422, 660+808, human RCT, negative).

Oral, Endodontics: Pulpotomy Success Rate - (424, 660, human RCT, positive), (425, 660+810, human RCT, negative), (426, 660, human RCT, neutral), (427, 660, human RCT, positive).

Oral, Gingival Recession Treatments - (448, 660, human RCT, neutral).

Oral, Oral Surgery: Connective Tissue Graft - (547, 660, human RCT, negative), (548, 660, human RCT, neutral).

Oral, Oral Surgery: Free Gingival Graft - (549, 660, human RCT, neutral), (550, 660, animal, positive), (551, 660+780, human negative).

Oral, Periodontium: Chronic Periodontitis - (576, 660, human negative), (577, 660, human RCT, neutral), (578, 660, human RCT, neutral).

Oral, Wound Healing: Palatal Wounds - (644, 660, human RCT, neutral), (645, 660, human RCT, neutral).

Oral, Analgesia - (648, 660, animal, positive), (649, 660+830, animal, positive), (650, 660+760+820, human RCT, neutral).

Pain, Ischemic - (659, 660+850, human RCT, negative).

Pain, Surgical: Tonsillectomy - (668, 445+660+970, human RCT, negative).

Pain, Surgical - (669, 660, human RCT, positive), (670, 660, human RCT, negative).

Reproductive System, Cesarean section - (679, 658+660, human, positive), (680, 660, human RCT, positive).

Reproductive System, Childbirth - (681, 660+850, human RCT, neutral).

Reproductive System, Nipple Trauma - (682, 660, human RCT, negative), (683, 660, human RCT, neutral).

Respiratory System, Olfactory Dysfunction - (714, 660, human RCT, neutral).

Surgery, Graft Donor Site - (749, 660, human, neutral).

Surgery, Rhinoplasty - (788, 660+830+840, human RCT, neutral).

Wound Healing, Leprosy - (886, 660, human, negative).

Strong Evidence For Health Harm Or No Effect: 3+ Human Studies With 65%+ Negative Outcomes

Hearing, Tinnitus, (188, 650+660, human, positive), (189, 660 vs 660+
808, human RCT, negative), (190, 660+808, human RCT, negative).

Muscle, Exercise: Running - (266, 660+850, human RCT, negative), (267, 660+850, human RCT, negative), (270, 660+850, human RCT, negative), (271, 660+850, human RCT, negative).

656-665nm Animal Study Evidence Outcomes (Mostly The 660nm Wavelength)

Next up, animal studies on the 660nm health effects - or 660nm health benefits. Some people think animal studies are very useful for inferring conclusions about humans and others don't. That philosophical discussion probably doesn't end soon.

But if you do see value in animal studies - for inferring conclusions about humans - then enjoy the section below:

Stong Animal Study Evidence: 3+ Animal Studies Available And 65%+ Positive:

Bone, Bone Repair - (2, 660, animal, positive), (3, 660, animal, positive), (4, 660, animal+in vitro, positive), (5, 660, animal, negative), (6, 660, animal, positive), (7, 660, animal, positive), (8, 660, animal, positive), (9, 660, animal, positive), (10, 660, animal, positive), (11, 660, animal, positive), (12, 660, animal, positive), (13, 660, animal, positive), (14, 660 vs 830, animal, positive), (15, 660, animal, positive), (16, 660 vs 808, animal, positive), (17, 660, animal, neutral).

Brain, Stroke (Preclinical) - (42, 660 animal+in vitro, positive), (43, 660 animal+in vitro, positive), (44, 660, animal, positive).

Circulation, Angiogenesis - (99, 660, animal, positive), (100, 660, animal+in vitro, positive), (101, 660 vs 790 vs 700 vs 530 vs 460, animal, positive).

Circulation, Hypertension - (106, 660, animal, positive), (107, 660, animal, positive), (108, 660, animal+in vitro, positive).

Edema, Paw (Vetirinary) - (151, 660, animal, positive), (152, 660, animal, positive), (153, 660, animal, positive), (154, 660 vs 684, animal, positive), (155, 660 vs 684, animal, positive), (156, 660 vs 684, animal, positive), (157, 660 vs 684, animal, positive).

Heart, Myocardial Infarction - (193, 660, animal, positive), (194, 660, animal, positive), (195, 660, animal, negative), (196, 660, animal, positive).

Joints, Arthritis - (225, 660, animal, positive), (226, 660 vs 808 vs 905, animal, neutral), (227, 660 vs 808 vs 905, animal, positive), (228, 660, animal, positive).

Ligaments, MCL injury - (236, 660, animal, positive), (237, 660, animal, positive), (237, 660, animal, negative).

Muscle, Muscle Injury - (292, 660, animal, positive), (293, 660 vs 780, animal, positive), (294, 660, animal, positive), (295, 660, animal, positive), (296, 660, animal, positive), (297, 660, animal, positive), (297, 660, animal, neutral), (298, 660, animal, positive).

Nervous System, PNS: Sciatic Nerve Injury - (311, 660 vs 808, animal, positive), (312, 660, animal, neutral), (313, 660 vs 830, animal, negative), (314, 660 vs 808, animal, positive), (315, 660, animal, positive), (316, 660, animal, positive), (317, 660, animal, positive), (318, 660, animal, positive), (319, 660, animal, neutral), (320, 660, animal, positive), (321, 660, animal, positive), (322, 660, animal, positive), (323, 660, animal, positive), (324, 660, animal, positive), (325, 660 vs 780, animal, positive), (326, 660 vs 830, animal, positive), (327, 660, animal, positive), (328, 660, animal, positive), (329, 660, animal, positive).

Nervous System, Spinal Cord - (330, 660, animal, positive), (331, 660, animal, positive), (332, 660, animal, positive), (333, 660, animal, positive).

Oncology, Tumor Cells - (342, 660+780, animal+in vitro, positive), (343, 660+810+940, in vitro, positive), (344, 660, in vitro, neutral), (345, 615+630+660+730, in vitro, positive), (346, 660 in vitro, neutral), (347, 660, in vitro, positive), (348, 660+780, in vitro, negative), (349, 660, in vitro, positive), (350, 660, in vitro, positive), (351, 660, in vitro, positive), (352, 660, in vitro, neutral), (353, 660+780, in vitro, positive), (354, 660 vs 808, in vitro, neutral), (355, 660, in vitro, positive), (356, 660, in vitro, negative), (357, 660 vs 780, in vitro, negative), (358, 660, in vitro, positive), (359, 660, animal+in vitro, positive), (360, 660, animal, positive), (361, 660, animal, positive), (362, 660, animal, positive), (363, 660, animal, neutral), (364, 660 vs 660+850, animal, positive), (365, 660, animal, positive), (366, 660 vs 800 vs 970, animal, positive), (367, 660, animal, negative), (368, 660, animal, negative), (369, 660, animal+in vitro, neutral) (911, 470+658, in vitro, positive).

Oral, Periodontium (Animal) - (580, 660, animal, positive), (581, 660+808, animal, positive), (582, 660, animal, positive) (583, 660, animal, neutral), (585, 660, animal, positive), (586, 660, animal, positive), (587, 660, animal, positive), (588, 660, animal, positive), (589, 660, animal, positive), (590, 660, animal, positive).

Pain, Hyperalgesia - (656, 660, animal, positive), (657, 660+830, animal, positive), (658, 660, animal, positive).

Pain, Neuropathic - (662, 660, animal, positive), (663, 660, animal, positive), (664, 660, animal, positive), (665, 660, animal, positive), (666, 660+980, animal, positive).

Respiratory System, Asthma - (693, 660, animal, positive), (694, 660, animal, positive), (695, 660, animal, positive), (696, 660, animal, positive).

Respiratory System, Lung Inflammation - (700, 660, animal, positive), (701, 660, animal, positive), (702, 660, animal, positive), (703, 660, animal, neutral), (704, 660, animal, neutral), (705, 660, animal, positive), (706, 660, animal, positive), (707, 660, animal, positive), (708, 660, animal, positive), (709, 660, animal, positive), (710, 660, animal, positive).

Surgery, Graft Integration - (750, 660, animal, positive), (751, 660, animal, positive), (752, 660 vs 830, animal, positive).

Surgery, Skin Flap - (753, 660, animal, positive), (754, 660+830, animal, positive), (755, 660, animal, positive), (756, 660, animal, positive), (757, 660, animal, positive), (758, 660, animal, positive), (759, 660, animal, positive), (760, 660+780, animal, positive), (761, 660+670, animal, positive), (762, 660, animal, positive), (763, 660, animal, positive), (764, 660+790, animal, neutral), (765, 660 vs 780, animal, positive).

Toxins, Snake Venom - (802, 660 vs 808 vs 660+808, animal, positive), (803, 660, animal, positive), (804, 660+780, animal, positive), (805, 660, animal, positive), (806, 660+780, in vitro, positive).

Wound Healing, Diabetic (Preclinical) - (842, 660+880, animal, neutral), (843, 660, animal, positive), (844, 660, animal, positive), (845, 660, animal, positive), (846, 660, animal, positive), (847, 640+660, animal, positive).

Wound Healing, Excision (Secondary Intention) - (852, 660, animal, positive), (853, 660, animal, positive), (854, 660, animal, positive), (855, 660 vs 830, animal, positive), (856, 660, animal, positive), (857, 660, animal, positive), (858, 660, animal, positive), (859, 660+780, animal, positive), (860, 660, animal, positive), (861, 660, animal, positive), (862, 660, animal, positive), (863, 660, animal, positive), (864, 660, animal, positive), (865, 660, animal, positive), (866, 660, animal, positive), (867, 660, animal, positive), (868, 660, animal, positive), (868, 660, animal, positive), (868, 660, animal, positive), (869, 660, animal, positive), (870, 660+700, animal, positive), (871, 660, animal, positive), (872, 633+660+950, animal, neutral), (873, 633+660, animal, positive), (874, 660, animal, positive), (875, 660+904, animal, positive), (876, 660+790, animal, positive), (877, 660, animal, positive), (878, 660, animal, positive), (879, 635+660, animal, positive), (880, 660, animal, positive).

Insufficient Or Neutral Or Conflicting Animal-Based Evidence:

Adipose Tissue, Lipolytic Activity - (1, 660+808, animal, neutral).

Bone, Implants - (20, 660 vs 808, animal, neutral).

Bone, Osteoblasts - (21, 660, animal, positive), (22, 637 vs 660 vs 808, in vitro, positive), (23, 660 vs 780, in vitro, positive), (24, 660 vs 780, in vitro, negative).

Bone, Osteoporosis - (25, 660+810+940, animal, positive).

Bone, Tibial Plateau Leveling Osteotomy (TPLO) - (26, 660+800+905+970, animal, neutral).

Brain, Alzheimer's Disease - (27, 660 vs 810, in vitro, positive), (28, 460+660, animal, positive), (29, 660, animal, positive).

Brain, Astrocyte - (30, 660, animal, positive).

Brain, Brain Injury - (31, 660 vs 780, animal, neutral), (898, 665 vs 730 vs 810 vs 980, animal, positive),

Brain, Cognitive Impairment - (32, 660 vs 810, animal, positive).

Brain, Cognitive Performance - (33, 660, animal, positive).

Brain, Metabolism - (35, 660+904, animal, positive).

Brain, Multiple Sclerosis, (36, 660+904, animal, positive).

Brain, Neuroinflammation - (37, 660, animal, positive).

Cells, Nitric Oxide - (64, 660, animal, positive), (65, 660 vs 808, in vitro, positive).

Circulation, Atherosclerosis - (102, 660+808, animal, positive).

Circulation, Hindlimb Ischemia - (105, 660, animal, positive).

Dermatology, Atopic Dermatitis - (119, 415 vs 525 vs 660 vs 830, animal, positive).

Dermatology, Melanin - (128, 660, animal, positive).

Dermatology, Skin Neuropeptides - (135, 470+660 vs 660+808, animal, neutral).

Diabetes Mellitus, Oxidative stress - (150, 660, animal, positive).

Eyes, Light-Induced Damage - (897, 484+511+664, animal, positive).

Eyes, Optic Nerve Injury - (163, 660, animal, positive).

Gastroenterology, Anal Fistula - (165, 660, animal, positive).

Gastroenterology, Anal Sphincter Injury - (166, 660, animal, positive), (167, 660, animal, positive).

Gastroenterology, Colitis - (168, 440 vs 660 vs 850, animal, positive).

Gastroenterology, Microbiome - (170, 660 vs 808, animal, neutral).

Gastroenterology, Smooth Muscle Function - (171, 254+350+365+470+532+660+808, ex vivo+animal, positive).

Heart, Heart Failure - (192, 660, animal, positive), (193, 660, animal, positive).

Heart, Heart Rate - (906, 658, animal, neutral).

Immunity, Endotoxemia - (197, 660, in vitro, positive), (198, 633+660, animal, neutral).

Immunity, Mast Cells - (207, 660 vs 820 vs 870 vs 880 vs 940 vs 950 vs all, animal, positive).

Immunity, Nitric Oxide Synthase - (210, 635 vs 660 vs 690 vs 905, animal, neutral).

Infections, Bacteria - (907, 658, animal, positive).

Infections, Staphylococcus - (223, 660, animal, positive).

Joints, Osteoarthritis (Knee) - (231, 660 vs 808, animal, positive).

Joints, Septic Arthritis (Experimental) - (234, 660, animal, negative).

Larynx, Reflux Laryngitis - (235, 780 vs 660+780, animal, positive).

Liver, Liver Cirrhosis - (239, 660, animal, positive).

Liver, Liver Injury - (240, 660, animal, negative).

Liver, Liver Regeneration - (241, 660, animal, neutral).

Liver, Liver Spheroid Transplantation - (242, 660, animal, positive).

Liver, Other - (243, 660 vs 780 vs 660+780, animal, positive).

Mechanisms, Original Research - (244, 660 vs 980, in vitro, positive), (245, 660, in vitro, positive), (246, 660, in vitro, positive), (247, 400 vs 450 vs 525 vs 660 vs 740 vs 810 vs 830 vs white light, in vitro, positive), (248, 660, animal, positive), (249, 660 vs 670 vs 830, in vitro, negative), (250, 660, in vitro, positive), (251, 360 vs 630 vs 660 vs 830 vs 400-800, in vitro, positive), (252, 660, in vitro, positive), (253, 660, in vitro, positive), (254, 660 vs 820 vs 880 vs 950, in vitro, positive).

Metabolic Health, Metabolism - (255, 660, animal, positive).

Muscle, Energy Metabolism - (262, 660, animal, positive), (263, 660 vs 830 vs 905, animal, positive).

Muscle, Exercise (Preclinical) - (286, 660, animal, positive), (287, 660 vs 830 vs 905, animal, positive).

Muscle, Muscle Atrophy - (289, 660, animal, neutral), (290, 660 vs 780, animal, negative).

Oncology, Safety - (337, 660+810, animal, positive).

Oral, Bone Repair - (379, 660, animal, positive).

Oral, Endodontics: Apexogenesis - (418, 660, animal, positive).

Oral, Endodontics: Formocresol Injuries - (420, 630+660, animal, positive).

Oral, Endodontics: Pulp Regeneration - (423, 660, animal+in vitro, positive), (424, 660, animal, positive).

Oral, Gingivostomatitis - (449, 660, animal, positive).

Oral, Oral Mucosa - (468, 660, animal, positive), (469, 660, animal, neutral).

Oral, Salivary Glands - (602, 660, animal, positive), (603, 660, animal, positive), (604, 660 vs 780, animal, positive), (605, 660, animal, positive), (606, 660 vs 780, animal, negative), (607, 660, animal, neutral), (608, 660, animal, neutral).

Oral, Submucous Fibrosis - (609, 660, animal, positive).

Oral, Tooth Replantation - (610, 660+808, animal, positive), (611, 660+808, animal, positive).

Oral, Tongue Ulcer - (621, 660, animal, positive).

Oral, Wound Healing - (646, 660, animal, positive), (647, 660, animal, positive).

Pain, Cancer Pain - (653, 660, animal, positive).

Pain, Mechanisms - (661, 660, animal, positive).

Pain, Nociception - (667, 660, animal, positive).

Radiation, X-rays (On Bone) - (675, 660, animal, positive).

Radiation, X-rays - (676, 660, animal, neutral), (677, 660+820+880+950, animal, neutral), (678, 660+820+880+950, animal, neutral).

Reproductive System, Testicle - (685, 660, animal, negative).

Reproductive System, Acute Respiratory Distress Syndrome - (687, 660, animal+in vitro, positive).

Respiratory System, COPD - (698, 660, animal, positive).

Respiratory System, Lung Fibrosis - (699, 660, animal, positive).

Respiratory System, Lung Injury (from LPS) - (711, 660, animal, positive).

Respiratory System, Lung Injury (In Sepsis) - (712, 660, animal, positive), (713, 520+660, animal, positive).

Respiratory System, Pleurisy - (715, 660, animal, positive).

Respiratory System - (716, 660, animal, positive).

Surgery, Hemilaminectomy - (719, 660, animal, negative).

Stem Cells & Regeneration, Osteogenesis - (729, 485 vs 532 vs 660 vs 810, in vitro, positive), (730, 660, animal+in vitro, positive), (731, 660, in vitro, positive).

Stem Cells & Regeneration, Hind Limb Ischemia - (734, 660, animal, positive).

Stem Cells & Regeneration, Wound Healing - (735, 660, animal+in vitro, positive).

Surgery, TRAM Flap - (767, 660, animal, positive), (787, 660+830, animal, positive).

Tendons, Achilles Tendon (+ Tibial Nerve) - (790, 660+808, animal, neutral).

Veterinary Medicine, Dogs: Wounds - (807, 830 vs 660+875+905, animal, positive), (808, 660+800+905+970, animal, neutral).

Veterinary Medicine, Horses: Tendinopathy - (809, 635+660+810+980, animal, positive).

Wound Healing, Doxorubicin-Induced Wounds - (849, 660, animal, positive), (850, 660, animal, positive).

Wound Healing, Incision (First Intention) - (882, 660, animal, neutral), (883, 640+660, animal, positive).

Wound Healing, Infected Wounds - (884, 660, animal, positive), (885, 660 vs 790 vs 660+790, animal, positive).

Animal-Based Evidence For Health Harm Or No Effect: 3+ Studies With 65% Or More Negative Outcomes

In Vitro And Ex Vivo Studies

Finally, in vitro ("in the glass") studies mostly, which are done in cell cultures and similar setups. Almost everyone agrees that it's harder to generalize from these studies to humans. Some people may still find some value in these studies, however.

Exclusive In Vitro Evidence Available With 3+ Studies And 65%+ Positive:

Cells, Energy Metabolism - (48, 660, in vitro, positive), (49, 415+540+660+810, in vitro, positive), (49, 660 vs 830, in vitro, positive).

Cells, Fibroblast Function - (54, 660, in vitro, positive), (55, 660, in vitro, positive), (56, 660, in vitro, neutral), (57, 660, in vitro, positive), (58, 660, in vitro, positive), (59, 660, in vitro, positive), (60, 660, in vitro, positive), (61, 660, in vitro, positive).

Cells, Proliferation - (66, 660, in vitro, positive), (67, 660, in vitro, positive), (68, 390 vs 415 vs 660, in vitro, positive), (69, 660, in vitro, positive), (70, 660, in vitro, positive), (71, 660, in vitro, negative), (72, 660, in vitro, positive), (73, 405 vs 405+630+660, in vitro, positive), (74, 660, in vitro, neutral), (75, 660, in vitro, positive), (76, 660+780, in vitro, positive), (77, 660, in vitro, positive), (78, 830 vs 570+660+950, in vitro, positive), (79, 660, in vitro, neutral), (80, 660, in vitro, positive), (902, 659, in vitro, positive), (903, 633 vs 658 vs 785, in vitro, neutral).

Cells, Scratch Wound Model - (91, 660, in vitro, positive), (92, 585+610+660, in vitro, positive), (93, 660+830, in vitro, positive), (94, 660, in vitro, positive), (95, 660, in vitro, positive), (96, 660, in vitro, positive), (97, 620 vs 660, in vitro, negative), (894, 661, in vitro, positive).

Gene Expression, Fibroblast - (172, 660, in vitro, positive), (173, 660, in vitro, positive), (174, 660, in vitro, positive).

Micro-Organisms, Bacteria: Multiple Strains - (258, 660 vs 830 vs 904, in vitro, positive), (259, 630 vs 660 vs 810 vs 905, in vitro, positive), (260, 660 vs 830 vs 904, in vitro, neutral).

Oral, Dentin - (397, 660 vs 810, in vitro, positive), (398, 660 vs 810, in vitro positive), (399, 660, in vitro, positive).

Oral, Periodontium (In Vitro) - (591, 660, in vitro, positive), (592, 660+940, in vitro, positive), (593, 445 vs 660, in vitro, positive), (594, 660, in vitro, positive), (595, 635 vs 660 vs 808 vs 980, in vitro, positive), (596, 660 vs 810 vs
980 vs 660+810 vs 810+980, in vitro, positive), (597, 635+660+808+980, in vitro, positive), (598, 660+808, in vitro, positive), (599, 400+450+525+660+740+810+830+white, in vitro, neutral), (600, 660, in vitro, positive), (601, 660, in vitro, positive).

Stem Cells & Regeneration, Adipose-Derived Stem Cells - (721, 660, in vitro, positive), (722, 660, in vitro, positive), (723, 660, in vitro, positive), (724, 660, in vitro, positive), (725, 660, in vitro, positive).

Stem Cells & Regeneration, Bone Marrow Stem Cells - (726, 660, in vitro, positive), (727, 660, in vitro, positive), (728, 660, in vitro, positive).

Stem Cells & Regeneration - (736, 660, in vitro, positive), (737, 660, in vitro, positive), (738, 660, in vitro, positive).

Insufficient Exclusive In Vitro Evidence (Not Included In Categories Above Or Below)

Bone, Cell Proliferation - (18, 630 vs 660 vs 780, in vitro, neutral), (19, 660 vs 780, in vitro, negative), (899, 625 vs 635 vs 645 vs 655 vs 665 vs 675 vs 810, in vitro, positive).

Cells, Adhesion - (47, 660, in vitro, positive).

Cells, Epigenetic Effects - (50, 660, in vitro, positive).

Cells, Epithelial + Mesenchymal Cells - (51, 660, in vitro, positive).

Cells, Extracellular Vesicles / Exosomes - (52, 660, in vitro, positive).

Cells, Fibroblast Differentiation - (53, 660, in vitro, positive).

Cells, Fibrosis - (62, 660, in vitro, positive).

Cells, Growth Factors - (63, 660 vs 780, in vitro, positive).

Cells, Protection - (81, 660 vs 780, in vitro, neutral), (82, 660, in vitro, positive), (83, 660, in vitro, positive), (84, 660, in vitro, neutral), (85, 660, in vitro, positive), (86, 660+780 vs 637, in vitro, neutral), (87, 660 vs 780, in vitro, positive), (904, 440 vs 523 vs 658 vs 823, in vitro, neutral).

Cells, ROS - (88, 660+830, in vitro, positive).

Cells, Scratch Migration Assay - (89, 660, in vitro, positive), (90, 660, in vitro, positive).

Cells - (98, 630 vs 660, in vitro, neutral).

Circulation, Endothelium - (104, 660 vs 820, in vitro, negative).

Circulation, Platelets - (112, 660, ex vivo, positive), (895, 662, in vitro, positive).

Circulation, Vasorelaxation - (114, 660, ex vivo animal, positive), (115, 660, ex vivo animal, positive).

Dermatology, Cell Protection - (120, 630 vs 660 vs 830 vs 850, in vitro, positive).

Dermatology, Cytokines - (121, 660, in vitro, positive).

Dermatology, Infrared Skin Damage - (900, 665-780+780-1400, in vitro, positive).

Diabetes Mellitus, Cellular Signalling - (147, 660, in vitro, positive).

Eyes, Diabetic Retinopathy - (162, 660, in vitro, neutral).

Gene Expression - (174, 660 vs 808, in vitro, positive).

Gene Expression, ATM And Pt3 - (175, 660 vs 808, in vitro, neutral).

Gene Expression, DNA Repair - (176, 660 vs 880, in vitro, neutral).

Gene Expression, Extracellular Matrix - (177, 660, in vitro, positive).

Hair, Hair Growth - (185, 415+525+660+830, in vitro, positive), (186, 415+660+830, in vitro, positive).

Heart, Cold Storage Of Heart - (191, 660, ex vivo, positive).

Immunity, Keratinocytes - (199, 520+660, in vitro, positive).

Immunity, Lymphocytes - (200, 660, in vitro, positive).

Immunity, Macrophage-Like Cells - (201, 660 vs 780, in vitro, positive).

Immunity, Macrophages (Alveolar) - (202, 660, in vitro, positive).

Immunity, Macrophages - (203, 660 vs 780, in vitro, neutral), (204, 660 vs 780, in vitro, positive), (205, 660, in vitro, neutral), (206, 660 vs 820 vs 870 vs 880, in vitro, positive).

Immunity, Monocytes - (208, 660+780, in vitro, neutral), (209, 660, in vitro, positive).

Immunity, Spleen - (211, 660-950, in vitro, positive).

Immunity, Stem Cells - (212, 660, in vitro, positive).

Immunity, T cells - (213, 415 vs 530 vs 630 vs 660 vs 830 vs 850 vs 940, in vitro, positive).

Infections, Virus (HIV-1) - (224, 660, in vitro, neutral).

Joints, Osteoarthritis (In Vitro) - (230, 660, in vitro, neutral).

Micro-Organisms, Bacteria: E coli - (256, 660+808, in vitro, neutral), (257, 660 vs 808, in vitro, neutral).

Muscle, Cell Viability - (261, 660+780, in vitro, negative).

Muscle, Myogenic Cells / Myogenesis - (300, 660, in vitro, positive).

Muscle, Myopathy - (301, 420 vs 470 vs 660 vs 850, in vitro, positive).

Nervous System, CNS - (302, 660 vs 860, in vitro, positive).

Oncology, Chemotherapy-Related DNA Damage - (334, 660, in vitro, neutral).

Oncology, Tumor Cells + Chemo - (339, 660, in vitro, positive).

Oncology, Tumor Cells + Radiation - (340, 660, in vitro, positive), (341, 660, in vitro, neutral).

Oral, Enamel - (417, 660, in vitro, neutral).

Oral, Endodontics (In Vitro) - (429, 660 vs 808, in vitro, positive), (430, 660, in vitro, positive), (431, 660, in vitro, neutral), (432, 660, in vitro, positive), (433, 660, in vitro, positive), (434, 660, in vitro, positive), (435, 660, in vitro, positive), (436, 660, in vitro, neutral), (437, 660, in vitro, neutral), (438, 660, in vitro, negative), (439, 660, in vitro, positive), (440, 660, in vitro, positive), (441, 660, in vitro, negative), (442, 660, in vitro, negative), (443, 660, in vitro, neutral), (444, 660, in vitro, positive), (445, 660, in vitro, neutral), (446, 660+810, in vitro, positive), (913, 447 vs 532 vs 658 vs 810 vs 980 vs 1064, in vitro, neutral).

Oral, Tissue Engineering - (612, 660, in vitro, positive).

PDT Papers With PBM Aspects, Cancer - (671, 660+850, in vitro, positive).

PDT Papers With PBM Aspects, AlClPc - (672, 660, in vitro, neutral).

PDT Papers With PBM Aspects, ClAlPc/NE - (673, 660+810, in vitro, positive).

Radiation, Gamma Radiation - (674, 660+820, in vitro, positive).

Reproductive System, Sperm - (684, 850 vs 625+660+850 vs 470 vs 625+660+470, in vitro, positive).

Respiratory System, Bronchial Hyperresponsiveness - (697, 660, in vitro, positive).

Stem Cells & Regeneration - (720, 660, in vitro, positive).

Stem Cells & Regeneration, Tenogenic Induction - (732, 660+905, in vitro, positive).

Stem Cells & Regeneration, Umbilical Cord Stem Cells - (733, 660, in vitro, positive).

Tendons, Cells - (801, 660, in vitro, positive).

Wound Healing, Flowable Wound Matrix - (881, 660, ex vivo, positive).

Exclusive In Vitro Evidence Available With 3+ Studies And 65%+ Negative:

No studies found here. Check my comments on this topic in the "advanced comments" section below:

Advanced Comments On The Categorization Of 660nm Wavelength Studies

For the science nerds out here, I'll lay out a few thoughts on how to interpret these results I've posted above:

  • The topic of wavelengths is extremely complex. After making a few cheatsheets for different wavelengths, I'm still not 100% sure on how to interpret these results. And, red and near infrared light wavelengths do have some overlap in their effects but also have diverging effects in a way.
  • To truly compare the effects of say, 630nm and 660nm, we'd need more comparison studies. Most comparison studies compare red to near infrared and only pick a single wavelength in each category. Ideally, you'll want to compare wavelengths within the red or near infrared spectrum in many different domains. That way, you learn with certainty whether companies need to offer panels with either a single or multiple wavelengths within a category.
  • However, you cannot deny that there's a very different level of evidence for different wavelengths. This 660nm and my earlier 810nm wavelength had tons of studies backing them. That's not true for 850nm, for instance.
  • Don't take this cheatsheet at face value - to truly understand any effects you'll still have to read the studies. All these studies aren't really uniform - I haven't even distinguished between RCT human studies and non-RCT (Randomized Controlled Trial) studies.
  • Hopefully, this document helps people who give lots of credence to animal studies and also those who only believe that human-based research matters. If you believe only human-based research matters (or more or less matters), then you ignore the in vitro and animal studies.
  • After speaking to Vladimir Heiskanen who created the excellent Excel file that's updated to today, I will have to agree with him on some points. Vladimir, for instance, states that ideally, we'd have Cochrane-style reviews on all the wavelengths and all health effects. I agree there, but we don't live in an ideal world and resources are limited. If I'd need to spend several weeks on each topic, creating the effects of 660nm on bone repair, then on osteoporosis, then on osteoblasts, etc, it would all take far too much time.
  • In the end, I do think these cheatsheats are very valuable, in that they help you see the broad evidence for each wavelength without spending too much time researching the topic. Doing so wasn't possible before but is now. And, yes, I'm very well aware the project is imperfect in the many ways I've described above.
  • I know many of the cuttoff points are somewhat arbitrary. Examples are the 65% positivity or negativity rate as a cutoff point.
  • I've included wavelengths from 656nm to 665nm, simply because many products emit light around that wavelength. Almost no product is perfect here and emits pricisely 660nm.

Best 660nm Wavelength Panels

Let's consider a few of the best 660nm wavelength red light therapy panels.

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For a regular update of the best 660nm panels, check out the product shopping tool of Light Therapy Insiders. As of this moment of writing, there are 43 different products that emit 660nm light. That number is almost too much to mention so I'll focus on the highest value and highest percentage 660nm panels out there below.

So let's consider a few of the best 660nm wavelength panels out there. I'm focusing on a high percentage of 660nm as well as high value (so, a high power output per $USD spent). Here's a top-3 of offerings that have been reviewed by Alex Fergus:

Of course, you might want another panel with other features. Such as a lower percentage of 660nm light, or low EMF, or low shipping or import duties, or other criteria. In those cases, check out the Light Therapy Insiders Shopping Tool to do your own searches and find the product that fits you best.

Conclusion: 660nm Light's Research Is Impressive!

I hope you loved my 660nm light cheatsheet. I put tons of work into this as you can see.

Hopefully, soon I'll get to doing the 620/630nm light studies but that's a ton of work too. My eyes became blurry sometimes after importing 200-300 studies per day.

Nevertheless, you now have much better understanding of what 660nm does for health!

This is a post by Bart Wolbers of Lighttherapyinsiders. Bart finished degrees in Physical Therapy (B), Philosophy (BA and MA), Philosophy of Science and Technology (MS - with distinction), and Clinical Health Science (MS), has had training in functional medicine, and is currently chief science writer.

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