therapies · education ·
Red Light Raised Collagen Density In 113 People. It Has Been Oversold Ever Since
A real controlled trial on skin, a sham-controlled one on hair, a plausible mechanism, and an industry that ran well past all three.
Photobiomodulation is the correct name for what most people call red light therapy, and the naming matters more than it sounds.
“Red light therapy” is what a panel is sold as. Photobiomodulation is what the research literature calls it, and searching under the right name is the difference between finding trials and finding adverts.
The trial worth knowing about
A prospective, randomized, controlled study enrolled 136 volunteers. Of those, 113 were randomly assigned to four treatment groups and 23 served as controls (Wunsch and Matuschka, Photomedicine and Laser Surgery, 2014).
The protocol: twice a week, 30 sessions, using either a red-only spectrum at 611 to 650 nm or a broader polychromatic spectrum at 570 to 850 nm.
Measured at baseline and after 30 sessions, with blinded evaluation of clinical photography:
- Skin roughness improved on computerized digital profilometry
- Collagen density increased on ultrasound measurement
- Skin complexion and skin feeling improved on patient assessment
- The blinded photographic evaluation confirmed significant improvement against controls
That is a real result with a real control group and a blinded assessor, which puts it well above most of what gets cited in this space.
The finding that should change what you buy
Here is the part nobody selling a panel will lead with.
The broadband polychromatic source showed no advantage over the red-light-only spectrum.
The researchers went in wondering whether covering more of the action spectrum would work better, since tissue repair responds to more than one wavelength. It did not.
So the expensive multi-wavelength array is not, on this evidence, buying you more than the simpler red one. That is a useful thing to know before spending.
What is actually happening, as far as anyone knows
The leading mechanism is specific enough to be checkable.
Light in the red and near-infrared range is absorbed by cytochrome c oxidase, unit four of the mitochondrial respiratory chain, which contains both heme and copper centres. The hypothesis is that photons dissociate inhibitory nitric oxide from the enzyme, increasing electron transport, mitochondrial membrane potential and ATP production (de Freitas and Hamblin, IEEE Journal of Selected Topics in Quantum Electronics, 2016).
Downstream, signalling through reactive oxygen species, cyclic AMP, nitric oxide and calcium activates transcription factors, which is the proposed route to changes in protein synthesis, cell migration and anti-inflammatory signalling.
Note the language throughout: leading hypothesis, appears to, proposed. That is the authors’ own framing, not our hedging.
Photobiomodulation has been known for almost 50 years but still has not gained widespread acceptance, largely due to uncertainty about the molecular, cellular, and tissular mechanisms of action.
de Freitas and Hamblin, 2016
Fifty years and the mechanism is still the open question. That is worth holding next to any advert promising certainty.
The hair evidence is better than we expected
We went looking to dismiss this one and could not.
A multicenter, randomized, sham device-controlled, double-blind study tested low-level laser devices for pattern hair loss. 269 subjects were randomized, 128 men and 141 women, treated three times a week for 26 weeks. The comparison was a sham device in a sealed identical package, investigators and subjects both blinded, and the evaluator of the digital photographs blinded as well (Jimenez et al., American Journal of Clinical Dermatology, 2014).
Mean terminal hair count at 26 weeks rose by 18.4 to 25.7 hairs per cm² in treated groups, against 1.6 to 9.4 in sham groups. The strongest comparisons reached p < 0.0001. No serious adverse events were reported.
That is a better design than most nutrition research on this site gets. A sham-controlled double blind with a blinded photographic assessor is what good looks like.
Two honest notes. The sham groups also improved, by up to 9.4 hairs per cm² in some arms, which is a reminder of how much movement you see from attention and measurement alone. And the authors call for further work on long-term effects and on optimising the laser modality.
What we are deliberately not covering
This therapy also gets claimed for fat loss, joint pain, thyroid function, testosterone and a good deal else.
Those are separate bodies of evidence of varying quality, and we have not verified them. So we are not repeating them, even the ones we suspect will hold up.
That is not caution for its own sake. An article that lists twelve benefits and verifies two is doing the same thing as the panel seller, just with better manners.
What we are and are not saying
| Claim | Our line |
|---|---|
| Photobiomodulation treats, cures or prevents disease | Never |
| A controlled trial found improved skin roughness and collagen density | Yes, with 113 treated against 23 controls over 30 sessions |
| Broadband panels outperform red-only | No. That trial found no advantage |
| The mechanism is established | No. It is the leading hypothesis, and the authors say so |
| A sham-controlled trial found increased terminal hair count | Yes, 269 people, 26 weeks, double blind |
| It does everything else the adverts claim | Unverified, and we are not repeating unverified claims |
What to ask before buying anything
Wavelength, not brightness. The trial used 611 to 650 nm for the effective red spectrum. A panel that will not tell you its wavelengths is telling you something.
Dose, not wattage. That study normalised to roughly 9 J/cm² in the red range. Energy delivered over time is the variable, and a brighter panel used for less time is not automatically more.
Session count. Thirty sessions over roughly four months at twice weekly. Not three.
Where the design shows up
The mechanism, if it holds, is that a pigment in your mitochondria absorbs red light and works slightly better afterwards.
Which is to say: a machine inside your cells is tuned to a frequency that arrives free, twice a day, at the two ends of daylight. The low red light of morning and evening is not an accident of the atmosphere so much as the condition this machinery grew up under.
A panel is an attempt to bottle the least mysterious thing in the world.
“Truly the light is sweet, and it is pleasing for the eyes to see the sun.” Ecclesiastes 11:7, NASB
The verse carries the conviction. One hundred and thirteen treated volunteers carry the number.
What to do this week
Get outside at the two ends of the day before you buy a panel.
Morning and evening light carry the red and near-infrared wavelengths this entire field is built on, they cost nothing, and the morning half has its own trial evidence for something a panel cannot do at all, which is setting your body clock.
If you then want to buy a device, ask for wavelengths and dose in writing, and do not pay extra for wavelengths that trial found added nothing.
Read this next: the dose companion, and the reason this literature contradicts itself: with red light, more is not better. For the free version with better evidence for a different job entirely: morning daylight worked as well as melatonin. And for how we grade a field this contested, two of medicine’s top editors say you can’t believe much of it.
Sources
- Wunsch A, Matuschka K. “A controlled trial to determine the efficacy of red and near-infrared light treatment in patient satisfaction, reduction of fine lines, wrinkles, skin roughness, and intradermal collagen density increase.” Photomedicine and Laser Surgery, 2014;32(2):93-100. https://pubmed.ncbi.nlm.nih.gov/24286286/
- Jimenez JJ, Wikramanayake TC, Bergfeld W, et al. “Efficacy and safety of a low-level laser device in the treatment of male and female pattern hair loss: a multicenter, randomized, sham device-controlled, double-blind study.” American Journal of Clinical Dermatology, 2014;15(2):115-127. https://pubmed.ncbi.nlm.nih.gov/24474647/
- de Freitas LF, Hamblin MR. “Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy.” IEEE Journal of Selected Topics in Quantum Electronics, 2016;22(3):7000417. https://pubmed.ncbi.nlm.nih.gov/28070154/
Article metadata retrieved from PubMed. Photograph from Pexels. Scripture quoted from the New American Standard Bible.
Educational content from True Health Solutions. We do not diagnose or prescribe, and nothing here is a substitute for care from someone who knows your history. The body heals. We write about what supports that design.
Questions people ask
- Does photobiomodulation actually work?
- For skin, there is a controlled trial worth taking seriously. 113 treated volunteers against 23 controls, twice weekly for 30 sessions, showed improved skin roughness on digital profilometry and increased collagen density on ultrasound, with blinded evaluation of photographs confirming it.
- What is photobiomodulation?
- Red and near-infrared light applied to tissue at non-thermal intensities. The leading mechanism is that light is absorbed by cytochrome c oxidase in the mitochondria, which appears to release inhibitory nitric oxide and increase electron transport and ATP production.
- Is the mechanism proven?
- It is the leading hypothesis rather than settled fact, and the review that lays it out says as much. The authors note the field has not gained widespread acceptance in nearly 50 years largely because of uncertainty about the mechanisms.
- Do more expensive panels work better?
- Not on the evidence we have. In that trial, a broadband polychromatic source covering 570 to 850 nm showed no advantage over a red-only 611 to 650 nm spectrum. More wavelengths did not mean more effect.
- Does red light work for hair loss?
- The evidence there is stronger than we expected. A multicenter, randomized, sham-controlled, double-blind study in 269 people over 26 weeks found terminal hair count rose 18.4 to 25.7 per square centimetre in treated groups against 1.6 to 9.4 in sham groups. The sham groups improving too is worth noticing.
- What about the claims for fat loss, thyroid and pain?
- Those are separate literatures with separate quality. We are not covering them here because we have not verified them, and saying nothing is better than repeating somebody's marketing.
