Category Archives: LLLT Wavelength

Lasers, Wavelength and Hair Growth

I have covered lasers and hair growth on this blog a number of times in the past, but have neglected the subject of late. However, a spate of new studies on this subject from around the world have put lasers back on my mind.

New Low Level Laser Therapy Hair Studies

When people discuss laser treatments for hair loss, low level laser therapy (LLLT) is usually what they mean. There have been many studies done in the past that show LLLT to be beneficial towards scalp hair growth. However, a large number of those studies have been of subpar quality (e.g., small sample size, bad photos) or biased (e.g., sponsored by a laser device manufacturer).

So this subject remains somewhat controversial. However, in the past month, three new studies have been published in support of low level laser therapy to treat hair loss:

  • A study from China concluded that low level laser therapy stimulates hair growth in mice via upregulating the expression of Wnt10b and β-catenin. Hair follicle count remained the same in LLLT treated mice versus untreated mice, but hair length increased in the former. If this holds true in humans, perhaps LLLT can really make existing hair stronger and less likely to die from the attack by dihydrotestosterone (or at least prolong the battle). However, long-lost hair is probably not going to return from LLLT.
  • A study from Iran tested a new laser scanner device (with a combination 655 nm red laser plus 808 nm infrared laser) by comparing it with a 655 nm red light laser hat. Both products led to hair growth benefits, but the laser scanner was superior. So laser wavelength may make a difference in outcome.
  • A study from Egypt on female hair loss sufferers found that combination LLLT+Minoxidil 5% treatment led to the better outcomes (measured via Ludwig scale classification and patient satisfaction) in comparison to LLLT only or Minoxidil 5% only treatments.

LLLT Wavelength: Blue Light > Red Light?

A new study via a European collaboration effort found that a UV-free blue light laser (453 nm wavelength) led to hair growth via prolongation of the anagen phase of the hair cycle, but a red light laser (689 nm length) did not do the same.

This result is surprising since most commercially available LLLT laser products (combs, caps, helmets) are of around 650 nm wavelength (i.e., in the red light spectrum). Interestingly, a 2015 study from South Korea found that 830 nm laser was superior to lower wavelength lasers (of 632 nm, 670 nm and 785 nm) when it came to hair growth in rats.

LLLT Light Wavelength
LLLT Laser Wavelength Spectrum.

The above mentioned European study also made an important finding: “We provide the first evidence that OPN2 and OPN3 are expressed in human hair follicles”.

Combining Fractional CO2 Laser and Hair Growth Factors

I discussed fractional lasers and hair growth in a post in 2015. Now a new study from China finds that a combination treatment using  carbon dioxide fractional laser treatment plus growth factors is significantly superior to using growth factors alone.

Fractional Laser for Stimulating Hair Regrowth

I have discussed low level laser therapy (LLLT) on this site on numerous occasions. I was very skeptical about LLLT when it started becoming trendy a decade or so ago. However, one peculiar phenomenon did make me have a modest degree of faith in the potential of lasers to grow hair. This phenomenon was the fact that people who got laser hair removal on their body hair sometimes complained that the laser actually grew more body hair! This is referred to as paradoxical hair stimulation.

For those with a lot of body hair that they are trying to permanently reduce, this phenomenon is thankfully very rare :-) For those like myself who get excited about anything that grows more hair (even if on the body), this phenomenon is unfortunately very rare :-(

In any event, the lasers that are used for at-home LLLT are much less powerful than the lasers that are used for laser hair removal at clinics. Home use low level laser therapy products such as the HairMax LaserCombs 9 and 12 cost just several hundred dollars, while much more powerful high-end lasers that are used to remove body hair cost tens of thousands of dollars. The power settings on professional laser hair removal devices are also very high and can easily damage skin if you go to an inexperienced clinic.

Fractional Laser to Stimulate Hair Growth via Wounding

The reason I thought about lasers again this week is because several days ago an interesting article from Catholic University of Korea was published in the Lasers in Surgery and Medicine journal. The conclusion of this article was that ablative fractional lasers appear to be effective in inducing hair regrowth via activation of the Wnt/Beta-Catenin pathway (based on a study done on mice). I have discussed the Wnt/Beta-Catenin pathway in numerous posts on this blog before.

However, I have never mentioned ablative fractional lasers before. Neither have I ever mentioned non-ablative fractional lasers on this blog before. Here is some information on ablative versus non-ablative lasers and on fractional lasers. Also see this excellent overview from 2012 of all four types of lasers being implied here.

Apparently, even before this latest development, there have already been a few published journal articles from Asian researchers covering both ablative and non-ablative fractional lasers and their positive impact on hair growth. For example see:

  • Abstract 1: Enhancing hair follicle regeneration by non-ablative fractional laser:  Assessment of irradiation parameters and tissue response. [Laser wavelength was 1550 nm].
  • Abstract 2: The effect of a 1550 nm fractional erbium-glass laser in female pattern hair loss. [Note that the erbium is an ablative laser].
  • Abstract 3: Fractional photothermolysis laser treatment of male pattern hair loss. [Also using the 1550 nm ablative erbium laser].

In the latest South Korean study in mice, it was found that the most effective (ablative) laser dosage was “the 10 mJ/spot and 300 spots/cm2 setting”. Hopefully some of these scientists will soon conduct studies on humans to get the most effective dosage on us neglected Homo Sapiens.

It does seem like light amplification by stimulated emission of radiation (LASER) can now legitimately be considered as a tool in the fight against hair loss. It is likely that in the years ahead, scientists will experiment with many newer lasers and with various duration and power settings. On both mice and humans, since we both look better with a plentiful fur or hair.