Thank you for the article — it’s been a gem, as I’m considering buying a laser cap for myself. After looking at the available options, I came to the conclusion that all these brands (Kiierr, RegrowMD, Capillus, illumiflow, RedRestore and others) are essentially reselling the same product, likely manufactured in one place, with just their logo on it. Is it possible that the research has been skewed towards considering this type of cap the most effective, only because it is widespread and no other options have been available until recently? Also, do we know where they come from and which one is considered the OG?
Hi, i appreciate your insight as I too am into learning more about advanced / scientific data regarding how all this works and what is most effective. My question is, have you looked into near infrared/IR + red light use combinations (810nm-860nm ish range) as I have recently started seeing more and more research articles stating that combo is far superior to only using red light in the 660nm wavelength?
Hi Alex, great question! Red + near-infrared (NIR) is genuinely interesting from a mechanistic standpoint, though it has significantly less research behind it than red light alone.
The leading belief regarding LLLT for hair growth is that cytochrome c oxidase, an enzyme within your cells, produces ATP when stimulated by red or NIR light which promotes hair growth. Since cytochrome c oxidase absorbs certain wavelengths in the red/NIR range better than others, the thinking goes that optimizing devices for those specific wavelengths should have the greatest effect. A second theory is that NIR penetrates deeper into the skin and is better able to stimulate deeper hair follicles, which is also mechanistically sound.
However, it's important to note that there haven’t been many clinical trials combining red + NIR light that produced measurable hair growth. Here are the main ones for further reading:
https://pubmed.ncbi.nlm.nih.gov/26048721/ – This animal study used the cytochrome c oxidase absorption peaks (632nm red, 670nm red, 785nm NIR, and 830nm NIR) on rats. It included 25 rats (5 per wavelength plus 5 controls) and saw the best results in the 830nm group. This is probably the strongest piece of research in favor of NIR, but it needs to be repeated in human trials with a larger sample size.
https://pubmed.ncbi.nlm.nih.gov/28513251/ – This clinical trial had 90 participants (30 using red light alone, 30 using red + NIR, and 30 controls). The red + NIR group saw an increase in hair count of 9.61 per cm² versus 9.16 per cm² for the red light alone. However, the red + NIR group used a scanning device while the red light group used a helmet, which makes the outcomes significantly less comparable. The difference in increased hair count for the red + NIR group was only about 5% (9.61 vs. 9.16). While still meaningful, we can’t draw specific conclusions from this study.
https://pubmed.ncbi.nlm.nih.gov/41366107/ – 21 participants used a broad-spectrum NIR hair growth device daily for 30 minutes over 20 weeks. The increase in hair count was only 1.33% which is far less than what we've witnessed in studies involving red-only devices, though it’s difficult to draw conclusions here because 30 minutes per day may be too high a dose, and the device used broad-spectrum NIR.
I also want to caution that while many clinical trials have shown light can promote hair growth, most of what we know about the mechanism remains theoretical. The cytochrome c oxidase link is plausible, but researchers are still trying to determine whether it’s the only factor at play or if multiple mechanisms are involved.
None of this is to say that NIR doesn’t play a role in hair growth. However, at the present moment, we can’t conclude how much of an impact it has with certainty. It’s worth watching, but claims about red + NIR being “far superior” are probably running ahead of the evidence.
I'm actually planning to write a full article breaking down the evidence for red + NIR versus red light alone. Stay tuned if you're interested, and thanks again for the great question!
Thank you for the article — it’s been a gem, as I’m considering buying a laser cap for myself. After looking at the available options, I came to the conclusion that all these brands (Kiierr, RegrowMD, Capillus, illumiflow, RedRestore and others) are essentially reselling the same product, likely manufactured in one place, with just their logo on it. Is it possible that the research has been skewed towards considering this type of cap the most effective, only because it is widespread and no other options have been available until recently? Also, do we know where they come from and which one is considered the OG?
Hi, i appreciate your insight as I too am into learning more about advanced / scientific data regarding how all this works and what is most effective. My question is, have you looked into near infrared/IR + red light use combinations (810nm-860nm ish range) as I have recently started seeing more and more research articles stating that combo is far superior to only using red light in the 660nm wavelength?
Hi Alex, great question! Red + near-infrared (NIR) is genuinely interesting from a mechanistic standpoint, though it has significantly less research behind it than red light alone.
The theory stems from this study: https://pubmed.ncbi.nlm.nih.gov/16144476/
The leading belief regarding LLLT for hair growth is that cytochrome c oxidase, an enzyme within your cells, produces ATP when stimulated by red or NIR light which promotes hair growth. Since cytochrome c oxidase absorbs certain wavelengths in the red/NIR range better than others, the thinking goes that optimizing devices for those specific wavelengths should have the greatest effect. A second theory is that NIR penetrates deeper into the skin and is better able to stimulate deeper hair follicles, which is also mechanistically sound.
However, it's important to note that there haven’t been many clinical trials combining red + NIR light that produced measurable hair growth. Here are the main ones for further reading:
https://pubmed.ncbi.nlm.nih.gov/26048721/ – This animal study used the cytochrome c oxidase absorption peaks (632nm red, 670nm red, 785nm NIR, and 830nm NIR) on rats. It included 25 rats (5 per wavelength plus 5 controls) and saw the best results in the 830nm group. This is probably the strongest piece of research in favor of NIR, but it needs to be repeated in human trials with a larger sample size.
https://pubmed.ncbi.nlm.nih.gov/28513251/ – This clinical trial had 90 participants (30 using red light alone, 30 using red + NIR, and 30 controls). The red + NIR group saw an increase in hair count of 9.61 per cm² versus 9.16 per cm² for the red light alone. However, the red + NIR group used a scanning device while the red light group used a helmet, which makes the outcomes significantly less comparable. The difference in increased hair count for the red + NIR group was only about 5% (9.61 vs. 9.16). While still meaningful, we can’t draw specific conclusions from this study.
https://pubmed.ncbi.nlm.nih.gov/41366107/ – 21 participants used a broad-spectrum NIR hair growth device daily for 30 minutes over 20 weeks. The increase in hair count was only 1.33% which is far less than what we've witnessed in studies involving red-only devices, though it’s difficult to draw conclusions here because 30 minutes per day may be too high a dose, and the device used broad-spectrum NIR.
I also want to caution that while many clinical trials have shown light can promote hair growth, most of what we know about the mechanism remains theoretical. The cytochrome c oxidase link is plausible, but researchers are still trying to determine whether it’s the only factor at play or if multiple mechanisms are involved.
None of this is to say that NIR doesn’t play a role in hair growth. However, at the present moment, we can’t conclude how much of an impact it has with certainty. It’s worth watching, but claims about red + NIR being “far superior” are probably running ahead of the evidence.
I'm actually planning to write a full article breaking down the evidence for red + NIR versus red light alone. Stay tuned if you're interested, and thanks again for the great question!