Photobiomodulation For Alopecia Areata

This article looks at the scientific evidence for photobiomodulation or low level laser therapy in the treatment of alopecia areata. There are a handful of studies on the topic. A couple of human studies using similar parameters have shown very promising results, while others using different parameters were not as successful.

What Is PBM – Photobiomodulation?

Photobiomodulation (PBM) is a term used to describe some therapeutic effects of light. Previously the term low-level laser therapy or cold laser therapy was used but photobiomodulation seems to be the accepted terminology going forward, it’s also a more encompassing term. Within the field photobiomodulation there are many biological effects described by exposure to (mainly) red or near infrared light with low power or low peak power output in the case of pulsed light.


Alopecia Areata

This is a unique hair loss condition that normally presents as patchy hair loss. Patches can regrow, the condition can improve or deteriorate. It’s progression is extremely unpredictable and can lead to total loss of body hair known as alopecia universalis. AA is believed to be an autoimmune condition. Many treatments have been put forward, often with scant evidence of efficacy and significant risk of side effects.


PBM & Hair Growth

One of the first observed effects of photobiomodulation was accelerated hair regrowth. During cancer experiments in the 1960s a scientist noticed that experimental animals who had been shaved and exposed to a weak red laser beam exhibited much faster hair regrowth than the animals which were shaved but not exposed to the red light. Shaved hair is clearly a different scenario to hair loss from alopecia but other studies have shown positive effects from photobiomodulation on autoimmune diseases. For example, photobiomodulation can lower thyroid antibodies and other markers of autoimmune thyroid dysfunction. See my article on that topic here [*].

Animal Studies

There are only a handful of alopecia areata studies which could be considered photobiomodulation, though there are others using different types of laser treatments. Two animal studies were conducted using the Lexington laser comb on a heat shock model and graft model of alopecia areata. These devices contain 9 red lasers (655 nm) with the constant output around 3.7 mw per laser beam [*]. The devices are generally used for pattern baldness, alopecia areata. Both studies report using the laser comb for 20 seconds daily, three times per week, for six weeks.

Red Laser Comb Results

In the first experiment animals were AA-like given patches with heat. By six weeks of mice that had laser comb treatment had full regrowth of hair. None of the animals in the placebo group showed regrowth [*]The second experiment used mice with either spontaneous (natural?) or graft induced alopecia universalis. Using the same treatment regimen as the first experiment this study showed no improvement from the laser comb [*].


Broadband  Red + Near-Infrared

A human trial using a device with a broad range of wavelengths showed significant improvement in alopecia areata. This device was a 1.26 Watt polarised light with a wavelength spectrum from 600 -1100nm, covering most of the visible red and invisible near infrared-A range. The light was pulsed and the treatment lasted three minutes on each patch. Treatment was every 1 to 2 weeks patients received 1 to 14 treatments. To further confuse things carpronium chloride 5% was applied twice daily to all of the patches, and oral antihistamines, cepharanthin, and glycyrrhizin were prescribed. The study concluded that almost half of the treated patches recovered faster than the untreated patches [*]. “Seven of 15 (46.7%) of the irradiated areas showed hair regrowth 1.6 months earlier than the nonirradiated areas.” 

Super-Pulsed Low Level Laser Therapy

These last two studies are by far the most promising. Both are human studies using near infrared lasers, 904 nm and 905 nm. Both lasers have a very high peak power output for photobiomodulation or low level laser therapy. The lasers are rapidly pulsed on and off with a short “on” cycle. This pulsing effect brings the average power way down and minimises heat buildup which could the beneficial effect from infrared light.

904nm Pulsed Laser

The first study was conducted in 2006 using a 904 nm near infrared laser with a peak power of 150 Watts [*]. This laser is pulsed at 40 Hz and the average power is only 1.2 mW. The diameter of the laser beam is 3 mm and the application time was 5 seconds per point. The laser probe was moved around different points on each treated patch until most of the area within the patch was treated. In patients who had two or more patches one of the patches was left untreated for comparison.

>95% Success

Almost all of the patches that received the active laser treatment had regrowth, and almost all of those patches were original color (at 3 months). This was with just four treatments over the course of one month. Treatment patches included scalp, eyebrow, beard and mustache. In positive responders (most people) initial regrowth was seen after week one (75%) or week two (25). The untreated control patches showed no re-growth in the follow-up period. 16 people were included in the study and the duration of alopecia areata was between one and six years for everyone included. No adverse effects were reported during or after treatment. Treated patches showed no further hair fall in that period either.

905nm Pulsed Laser

A similar study was published in 2013 [*]. This used a 100 Watt peak power, 905 nm laser. The laser was pulsed at 5000 hz. Average power is not stated. Participants had 3 sessions per week, on consecutive days, for 4 weeks. Dose was listed as 1.5J/cm2 on the patch areas. Treatment time was determined then by the size of the patches. The follow up examination was at 3 months from the start of treatment (2 months after the final treatment) same as the previous study. This study used the Endolaser 422 which lists average powers for the 905 nm laser as 25 mw or 100 mw. The study claims 1.5J/cm2  was delivered in 2 minutes. Dosing isn’t exactly clear from my reading. The model used in this study is listed for sale on some sites [*].


Doubling Hair Count In 4 Weeks

23 people took part in this study which treated patches on the scalp only. One patch from each participant was left untreated for comparison. The treated hair patches showed highly significant improvement in hair count after treatment, changes in untreated patches were not significant. Hair count had almost doubled in the treated patches by one month, slightly more improvement was noted by three-month period. Analysis by visual assessment of the patches showed a similar effect from photobiomodulation therapy in this case.



Pulsed 904 nm and 905nm looks very promising for AA. Both studies used pretty high peak powered lasers and relatively short treatment times. There are some devices with similar parameters available for less than the Endolaser 422, which comes in at up to 1500 USD. The Handy Cure s’ and similar Terraquant devices have multi-Watt peak power 904/5 laser output. The Handy Cure s’ sells for about 460 USD on ebay [*] and it seems similar to Terraquant devices except for the lower price. See my article on Handy Cure s’ and Terraquant parameters here, halfway down this page for more information on that [*]Hedlab also creates devices that might be close to those used in the last two studies. Hedlab sells 60 Watt pulsed 905nm devices with 1 [*] or 4 [*] laser heads. You can see my article on my Hedlab device here [*].

Handy Cure s’

25 Watt peak power, 904nm, sells for about 460 USD on ebay [*].


Hedlab Super Pulsed 60 Watt peak power 905nm lasers.


This is a Super Pulsed laser with 60 W peak power, average power less than or equal to 60 mw, 905nm near infrared. These are quite small and light devices compared to others.


There is also a version listed with 4 of these 60W 905nm super pulsed modules that run at the same time, allowing for faster treatment of multiple spots. The higher powered lasers have very high pulse rates, up to 30,000hz.

If you want to get more familiar with some of the technical aspects of dosing try reading my article on the subject.

This article is for discussion purposes only, please do your own research and support resonantfm if you find my research useful.