Hair Loss Sucks. How Light Can Help, According to Science

Hair loss is depressing. What therapy works well and has no side effects?

Red light therapy restores hair growth in dormant follicles. The process works as well as minoxidil, the FDA approved topical treatment. Unlike minoxidil or FDA approved finasteride, red light therapy has no long term or short-term side effects.

Summary of red light therapy hair growth studies
Summary of red light therapy hair growth studies. Click image for larger version.  View original Journal of Cutaneous and Aesthetic SurgeryOpens in a new tab.

To date, the FDA has approved sports caps, headbands, laser combs and helmets for hair regrowth at home, without a prescription.

Capillus Pro 272

How Red Light Therapy Grows Hair

HairMax therapy “before”
HairMax therapy “during”
HairMax therapy “after”

The precise mechanism for red light therapy’s effect on hair growth is not yet known, but there are several strong theories.

Improved Blood Flow

Novaa Light Pro Red Light Therapy
Novaa Light Pro Red Light Therapy

Red light therapy stimulates blood flow, which might have some part in its ability to trigger hair growth.

Researchers theorize that improved blood flow is how Minoxidil helps dormant follicles to grow hair again.

LaserCap HD Plus

Red light therapy opens blood vessels by dislocating nitric oxide from the mitochondria to the blood vessels. There are thousands of mitochondria in every cell. They house the factories where biological energy is produced.

When the photons absorb in the mitochondria, they knock loose nitric oxide into the arteries. Nitric oxide triggers dilation, making the blood vessels larger. More blood, oxygen and nutrition reach the hair follicles.

The theory is that the hair follicles benefit from the blood, oxygen and nutrition supply.

HairMax PowerFlex cap

Improved Adenosine Triphosphate Output

The nitric oxide that the photons knocked loose had been inhibiting cellular energy production. With that nitric oxide out of the way, the mitochondria make more adenosine triphosphate (ATP).

In our trillions of cells, we have quadrillions of mitochondria making ATP cellular energy.

ATP molecules act as batteries, powering every biological function.

The theory is that red light therapy gives hair follicles the energy required to make hair.

Growth Factor Stimulation

Women choose from minoxidil and light therapy. Oral finasteride does not work for women. Pregnant women must maintain distance as finasteride causes fetal damage.

Red light therapy enhances production of growth factors. These proteins stimulate cell replication as part of the healing process.

One study found that red light therapy heals wounds faster because it promotes platelet-derived growth factor (PDGF) and transforming growth factor (TGF)-β[1].

There are multiple growth factors involved in the hair growing process[2].

Part of red light therapy’s effect on hair growth might be due to its ability to stimulate more growth factor activity on the scalp.


[1] Keskiner I, Lutfioğlu M, Aydogdu A, Saygun NI, Serdar MA. Effect of Photobiomodulation on Transforming Growth Factor-β1, Platelet-Derived Growth Factor-BB, and Interleukin-8 Release in Palatal Wounds After Free Gingival Graft Harvesting: A Randomized Clinical Study. Photomed Laser Surg. 2016 Jun;34(6):263-71. doi: 10.1089/pho.2016.4094. Epub 2016 Apr 18. Erratum in: Photomed Laser Surg. 2018 Jan;36(1):58. PMID: 27088277; PMCID: PMC4892223.

[2] Lin WH, Xiang LJ, Shi HX, Zhang J, Jiang LP, Cai PT, Lin ZL, Lin BB, Huang Y, Zhang HL, Fu XB, Guo DJ, Li XK, Wang XJ, Xiao J. Fibroblast growth factors stimulate hair growth through β-catenin and Shh expression in C57BL/6 mice. Biomed Res Int. 2015;2015:730139. doi: 10.1155/2015/730139. Epub 2015 Jan 1. PMID: 25685806; PMCID: PMC4313060.

Scientifically and FDA Validated Hair Growth Light Therapy Options

A 2021 study published in The Journal of Clinical and Aesthetic Dermatology listed the FDA-approved options that also had published science to back their use.

The FDA has approved 32 red light therapy devices to regrow hair.

Authors found seven double-blinded, randomized and placebo-controlled trials testing FDA-approved devices on hair growth.

These included studies on twenty sports caps, two headbands, four combs, and six helmets.

The study authors found that all devices worked equally well to increase hair density compared to controls.

LEDs were as effective as lasers at growing hair.

Men and women grew hair equally well on average when using comb or helmet hair growth devices.

The authors of the meta analysis determined that the devices (listed below) worked equally well for men and women.

Bosley Revitalizer 272
Bosley Revitalizer 272

Below are the LED and laser configurations of the devices that successfully grew hair in the studies.

Hair Growth Sports Cap Configurations

Sports Cap Hair Growth Devices Lights and Wavelengths
Capillus 82 Ultra 82 laser diodes, 650 nm red
Capillus 202 Plus 202 laser diodes, 650 nm red
Capillus 272 Pro 272 lasers diodes, 650 nm red
HairMax ReGrow 272 272 laser diodes, 655 nm red
LaserCap LCPRO 224 laser diodes, 650 nm red
LaserCap SD 80 laser diodes, 650 nm
LaserCap HD 224 laser diodes, 650 nm
LaserCap HD+ 304 laser diodes, 650 nm
Illumiflow 148 148 laser diodes, 650 nm
Illumiflow 272 272 llaser diodes, 650 nm
Grivamax 148 148 laser diodes, 650 nm
Grivamax 272 272 laser diodes, 650 nm
Revian Red 119 light emitting diodes, 620-660 nm
Dermascalp 148 148 laser diodes, 650 nm
Dermascalp 272 272 laser diodes, 650 nm
Bosley Revitalizer 164 164 laser diodes, 650 nm
Bosley Revitalizer 272 272 laser diodes, 650 nm
Kiierr 148 148 laser diodes, 650 nm
Kiierr 272 272 laser diodes, 650 nm
Kiierr 272

Hair Growth Comb Configurations

Comb Hair Growth Devices Lights and Wavelengths
HairMax LaserComb 7 7 laser diodes, 655 nm red
HairMax LaserComb 9 9 laser diodes, 655 nm red
HairMax LaserComb 12 12 laser diodes, 655 nm red
Nutrastim Laser Hair Comb 12 laser diodes, 655 nm
iRestore Professional

Hair Growth Headband Configurations

Headband Hair Growth Devices Lights and Wavelengths
HairMax LaserBand 41 41 laser diodes, 655 nm red
HairMax LaserBand 82 82 laser diodes, 655 nm red
Does red light therapy help hair growth? The Theradome LH80 is a red light therapy device that grows hair.
Theradome LH80

Hair Growth Helmet Configurations

Helmet Hair Growth Devices Lights and Wavelengths
Apira iGrow 21 laser diodes, 655 nm red

30 light emitting diodes, 655 nm red

Freedom Laser Therapy iRestore Essential 21 laser diodes, 655 nm
30 light emitting diodes, 655 nm red
Freedom Laser Therapy iRestore Professional 82 laser diodes, 655 nm
200 light emitting diodes, 655 nm red
Theradome LH 40 EVO 40 laser diodes, 678 nm
Theradome LH 80 EVO 80 laser diodes, 678 nm
iHelmet 200 200 laser diodes, 650 nm
iHelmet 200

How Well these Devices Worked

Hair density is the amount of hair per square centimeter. The studies show that these devices significantly improved hair density on subjects’ heads.

This analysis included improvement details only for four of the devices. I’m not sure why so much data is missing.

HairMax LaserComb 12

Below are the improvements as stated in the meta analysis. If the hair density result is missing here, that’s because it’s missing in the original meta analysis.

Revian Red Hair Growth System

Still, the results that are included are interesting, as they significantly improved hair density.

Comb Hair Density Improvements

Comb Hair Growth Devices Hair Density Improvement
HairMax LaserComb 7 93.5% improvement for 28 men, 7 women
HairMax LaserComb 9 110 men, additional 19.8 hairs/cm^2;

11 men, 21 women (8 significant improvement, 20 moderate improvement, 4 no improvement)

HairMax LaserComb 12 148 men, 121 women, additional 15.27 hairs/cm^2

 

Helmet Hair Density Improvements

Helmet Hair Growth Devices Hair Density Improvement
Apira iGrow 47 women, 37% increased hair count
iGrow hair growth helmet

How Often These Devices Were Used for Hair Growth

The reported studies used the devices according to manufacturer directions. If you are shopping for red light therapy, this section should be helpful.

Normally you see a relationship between power and time. Powerful devices have shorter session lengths.

The relationship between power and time breaks down with these FDA approved hair growth devices.

Most devices come with instructions for 20 or 30 minutes of use per session. A few require much less time, despite not being more powerful.

I asked HairMax about the disconnect. Why didn’t devices with more light have shorter treatment times? I would think that a light with 272 diodes would offer a faster treatment time than one with 148 diodes.

The answer didn’t help much, it was a form of “it depends on how much hair you want to grow,” or maybe she said “how fast you want to grow your hair.” The conversation was quite a while ago.

If you are including time management in your shopping criteria, pay attention to the schedules below. The HairMax and Nutrastim combs, and the HairMax headbands have remarkably short treatment times.

FDA Approved Sports Cap Hair Growth Treatment Schedules

Sports Cap Hair Growth Devices Protocol
Capillus 82 Ultra 30 minutes 3-4x week
Capillus 202 Plus 30 minutes 3-4x week
Capillus 272 Pro 30 minutes 3-4x week
HairMax ReGrow 272 30 minutes 3x week
LaserCap LCPRO 36 minutes every other day
LaserCap SD 30 minutes every other day
LaserCap HD 30 minutes every other day
LaserCap HD+ 30 minutes every other day
Illumiflow 148 30 minutes every other day
Illumiflow 272 30 minutes every other day
Grivamax 148 30 minutes every other day
Grivamax 272 30 minutes every other day
Revian Red 10 minutes every other day
Dermascalp 148 30 minutes 3x week
Dermascalp 272 30 minutes 3x week
Bosley Revitalizer 164 30 minutes every other day
Bosley Revitalizer 272 30 minutes every other day
Kiierr 148 30 minutes every other day
Kiierr 272 30 minutes every other day

 

FDA Approved Hair Growth Comb Treatment Schedules

Comb Hair Growth Devices Protocol
HairMax LaserComb 7 15 minutes 3x week
HairMax LaserComb 9 11 minutes 3x week
HairMax LaserComb 12 8 minutes 3x week
Nutrastim Laser Hair Comb 8 minutes 3x week

 

FDA Approved Hair Growth Headband Treatment Schedules

Headband Hair Growth Devices Protocol
HairMax LaserBand 41 3 minutes 3x week
HairMax LaserBand 82 90 seconds 3x week

 

FDA Approved Hair Growth Helmet Treatment Schedules

Helmet Hair Growth Devices Protocol
Apira iGrow 25 minutes every other day
Freedom Laser Therapy iRestore Essential 25 minutes every other day
Freedom Laser Therapy iRestore Professional 25 minutes every other day
Theradome LH 40 EVO 20 minutes 4x week
Theradome LH 80 EVO 20 minutes 2x week
iHelmet 200 30 minutes every other day

 

How Long Red Light Therapy Takes to Grow Hair, According to Science

Red light therapy starts growing hair in as little as five weeks, but a 6-month schedule is much more realistic.

Red Light Therapy Grows Hair in as Little as 4 Weeks

Most studies report a period of 30 to 50 weeks to grow hair using red light.

Two studies report growing hair much faster.

A study published in Photobiomodulation, Photomedicine and Laser Surgery reports that red light therapy grew hair in only 5 weeks.

The researchers tested the effect of red light on 25 men with androgenetic alopecia. The subjects were 25 to 40 years old.

The men received red light therapy twice a week for ten weeks.

At different points in the study, the authors photographed the men’s hair. They gave the photographs evaluators to record hair density. The evaluators did not participate in the therapy phase so as not to bias their tallies.

The hair density increased a significant amount at week 5 of the study. The hair density continued to increase through the 20th and final week of therapy. The hair density stopped increasing when therapy stopped.

A study published in Lasers in Medical Science reports that light therapy grew hair in only 4 weeks[3].

This research tested the effect of 417 nm blue light on hair growth.

Twenty-eight subjects with androgenetic alopecia received blue light treatment two times per week, for ten weeks.

After only 1 month, the hair density and shaft thickness increased in 90% of the subjects.

There were no adverse events. Weirdly, some subjects had darker hair after therapy.

The authors concluded, “Light therapy is a promising therapy for patients affected by androgenetic alopecia and other diseases characterized by hair loss.”

This research tested the effect of 417 nm blue light on hair growth.

Twenty-eight subjects with androgenetic alopecia received blue light treatment two times per week, for ten weeks.

After only 1 month the hair density and shaft thickness increased in 90% of the subjects.

There were no adverse events. Weirdly, some subjects had darker hair after therapy.

The authors concluded that “light therapy is a promising therapy for patients affected by androgenetic alopecia and other diseases characterized by hair loss.”


[3] Lodi G, Sannino M, Cannarozzo G, Giudice A, Del Duca E, Tamburi F, Bennardo L, Nisticò SP. Blue light-emitting diodes in hair regrowth: the first prospective study. Lasers Med Sci. 2021 Oct;36(8):1719-1723. doi: 10.1007/s10103-021-03327-9.Opens in a new tab. Epub 2021 Jun 8. PMID: 34101089.

Red Light Therapy Grows Hair in 38-40 Weeks

Red light therapy grows hair in 38 to 40 weeks, according to a study published in the Journal of Cutaneous and Aesthetic Surgery in 2021.

This study tested the effectiveness of an FDA approved therapy helmet. Subjects were between 18 and 40 years old and had mild, moderate and severe androgenetic alopecia.

The subjects’ ages ranged from 18 to 40 years old. They had moderate to severe androgenetic alopecia.

The therapy grew hair for 80% of the 1,383 subjects, with significant results at 38 to 40 weeks.

Authors concluded that those with mild androgenetic alopecia should use the helmet at least 133 times over 38 weeks.

Those with moderate to severe androgenetic alopecia should use the helmet at least 142 times over 40 weeks.

Women had good results, but the men’s results were better. Weirdly, those subjects who had dandruff, itchiness or a rash before treatment started had better results.

What Kind of Red Light Therapy Grows Hair?

Red, infrared, blue and ultraviolet light stimulate hair growth. The science concentrates on red light, so we have the most evidence supporting its use.

Many Wavelengths Grow Hair

In a 2022 meta analysis published in Dermatology Surgery, authors reported on 36 published studies that tested red light therapy on 966 subjects.

They concluded that:

  • ultraviolet and infrared light grow hair on people with alopecia areata
  • red and infrared light grow hair on people with androgenetic alopecia

They did not report on red light for alopecia areata, or on ultraviolet for androgenetic alopecia.

Please be aware that ultraviolet can be harmful and is supported by only a small amount of evidence.

Red Light Grows Mouse Hair

Alopecia areata is an autoimmune disease. The lymph system produces T-cells in and around the hair follicles.

A 2012 study published in Lasers in Medicine & Science supports using red light to grow hair[4], based on its success growing hair on mice.

Researchers studied the effects of the HairMax LaserComb on mice with non-scarring alopecia.

In this randomized, placebo-controlled study, mice received 655 nm red light for 6 weeks.

Treatment times were just 20 seconds long.

The sham group received the same treatment but with a device that did not emit the therapeutic light.

All the mice in the treatment group had significantly more hair per square centimeter (i.e., the hair density), and significantly thicker hair shafts. The sham group had no changes.


[4] Wikramanayake TC, Rodriguez R, Choudhary S, Mauro LM, Nouri K, Schachner LA, Jimenez JJ. Effects of the Lexington LaserComb on hair regrowth in the C3H/HeJ mouse model of alopecia areata. Lasers Med Sci. 2012 Mar;27(2):431-6. doi: 10.1007/s10103-011-0953-7Opens in a new tab.. Epub 2011 Jul 9. PMID: 21739260.

Red Light Grows Hair on Men with Androgenetic Alopecia

In a study published in the journal Photobiomodulation, Photomedicine and Laser Surgery, the authors tested the effect of red light on 25 men with androgenetic alopecia.

The men’s ages ranged between 20 and 54 years old. They received red light therapy twice a week for ten weeks.

At different points in the study, the authors photographed the men’s hair. They gave the photographs to “blinded” evaluators to record hair density. The evaluators did not participate in the therapy phase so as not to bias their tallies.

The men’s hair density had a significant increase starting at week 5 of the study. The hair density continued to increase through the 20th and final week of therapy. The hair density stopped increasing when therapy stopped.

Red Light Grows Hair on Men and Women with Androgenetic Alopecia

In a 2021 meta analysis published in the Journal of Cutaneous and Aesthetic Surgery in 2021[5], researchers reported that red light grows hair on men and women with androgenetic alopecia.

The authors gathered the 15 largest randomized controlled studies of red light therapy for hair growth. They consolidated the results to see what conclusions they could draw.

The authors concluded that red light therapy is a safe, non-invasive and effective treatment for androgenetic alopecia for both men and women.


[5] Pillai JK, Mysore V. Role of Low-Level Light Therapy (LLLT) in Androgenetic Alopecia. J Cutan Aesthet Surg. 2021 Oct-Dec;14(4):385-391. doi: 10.4103/JCAS.JCAS_218_20Opens in a new tab.. PMID: 35283601; PMCID: PMC8906269.

Conclusion

Red light therapy is a non-invasive, safe and effective hair growth treatment available without a prescription for at home use.

FDA approved devices include headbands, helmets, sports caps and combs.

Most devices require 20 to 30 minutes, but a few have very short treatment session times.

How to Buy Red Light Therapy for Hair Growth

 

Here are the devices mentioned in this article, below.

Table: Hair growth therapy lights

Apira Science iGrowOpens in a new tab. 25 min. every other day
Freedom Laser Therapy iRestore EssentialOpens in a new tab. (View at AmazonOpens in a new tab. or at iRestoreLaserOpens in a new tab.) 25 min. every other day
Freedom Laser Therapy iRestore ProfessionalOpens in a new tab. (View at AmazonOpens in a new tab. or at iRestoreLaserOpens in a new tab.) 25 min. every other day
Theradome LH80Opens in a new tab. 20 min. 2x week
Theradome LH40Opens in a new tab. 20 min. 4x week
iHelmet 200Opens in a new tab. 30 min. every other day
HairMax LaserBand 41Opens in a new tab. (View at AmazonOpens in a new tab. or at HairMaxOpens in a new tab.) 3 min. 3x week
HairMax LaserBand 82Opens in a new tab. (View at AmazonOpens in a new tab. or at HairMaxOpens in a new tab.) 1.5 min. 3x week
HairMax LaserComb 9Opens in a new tab. (View at AmazonOpens in a new tab. or at HairMaxOpens in a new tab.) 11 min. 8x week
HairMax LaserComb 12Opens in a new tab. (View at AmazonOpens in a new tab. or at HairMaxOpens in a new tab.) 8 min. 8x week
Capillus 82 UltraOpens in a new tab. 6 min. every day
Capillus 202 PlusOpens in a new tab. 6 min. every day
Capillus 272 ProOpens in a new tab. 6 min. every day
HairMax ReGrow 272Opens in a new tab. 30 min. every other day
LaserCap SDOpens in a new tab. 30 min. every other day
LaserCap HDOpens in a new tab. 30 min. every other day
LaserCap HD+Opens in a new tab. 30 min. every other day
Illumiflow 148Opens in a new tab. 30 min. every other day
Illumiflow 272Opens in a new tab. 30 min. every other day
Grivamax 148Opens in a new tab. 30 min. every other day
Grivamax 272Opens in a new tab. 30 min. every other day
Revian RedOpens in a new tab. 10 min. every day
Dermascalp 148Opens in a new tab. 30 min. every day
Dermascalp 272Opens in a new tab. 30 min. every day
Bosley Revitalizer 164Opens in a new tab. 8 min. every day or 30 min. every other day
Bosley Revitalizer 272Opens in a new tab. 8 min. every day or 30 min. every other day
Kiierr 148Opens in a new tab. 30 min. every other day
Kiierr 272Opens in a new tab. 30 min. every other day

 

Red light therapy is as effective as topical and oral FDA approved medications for hair growth, but red light therapy has none of the side effects they have.

Caroline Bogart

I research the bloody hell out of everything that interests me, then translate it into blog posts to solidify my knowledge and share the information.

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