How Often to Use Red Light Therapy for Hair Growth: Answer
Hair loss is depressing but not permanent. Once you have a hair growth device, how often should you use it?
Takeaways
I listed four FDA-approved red light therapy hair growth devices below.
Each should be used three times per week.
What’s different is the amount of time per session, which ranges from 1.5 to 20 minutes.
Use your red light therapy for hair growth three times per week unless the directions instruct otherwise.
TABLE: Hair Growth Red Light Therapy Suggested Schedules
Device | Image | Session | Schedule | View |
HairMax LaserBand 82 |  | 1.5 minutes | Three times per week | |
HairMax LaserComb 12 |  | 11 minutes | Three times per week | |
HairMax PowerFlex Laser Cap 272 |  | 7 minutes | Three times per week | |
iRestore Professional |  | 25 minutes | Three times per week |
How Often to Use Red Light Therapy for Hair Growth
A 2021 study published in The Journal of Clinical and Aesthetic Dermatology listed the FDA-approved options with published science backing their use.
The 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.
The authors of the meta-analysis determined that the devices (listed below) worked equally well for men and women.
Below are the LED and laser configurations of the devices that successfully grew hair in the studies.
Treatment Schedules
The reported studies used the devices according to the manufacturer’s directions. This section should be helpful if you are shopping for red light therapy.
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 have 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 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.
To add time management to your shopping criteria, consider the schedules below.
The HairMax and Nutrastim combs and headbands have remarkably short treatment times.
TABLE: Sports Cap Treatment Schedules
| FDA-Approved Sports Cap Hair Growth Treatment SchedulesSports Cap Hair Growth DevicesProtocol | |
|---|---|
| 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 |
TABLE: Comb Treatment Schedules
| FDA-Approved Hair Growth Comb Treatment SchedulesComb Hair Growth DevicesProtocol | |
|---|---|
| HairMax LaserComb 7 | 15 minutes 3x a week |
| HairMax LaserComb 9 | 11 minutes 3x a week |
| HairMax LaserComb 12 | 8 minutes 3x a week |
| Nutrastim Laser Hair Comb | 8 minutes 3x a week |
TABLE: Headband Treatment Schedules
| FDA-Approved Hair Growth Headband Treatment SchedulesHeadband Hair Growth DevicesProtocol | |
|---|---|
| HairMax LaserBand 41 | 3 minutes 3x week |
| HairMax LaserBand 82 | 90 seconds 3x week |
TABLE: Helmet Treatment Schedules
| 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 a week |
| Theradome LH 80 EVO | 20 minutes 2x week |
| iHelmet 200 | 30 minutes every other day |
Device Configurations
Lasers, LEDs, red and infrared combinations all worked to re-grow hair.
TABLE: FDA-Approved Hair Growth Sports Caps
| 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 laser 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 |
TABLE: FDA-Approved Hair Growth Combs
| 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 |
TABLE: FDA-Approved Hair Growth Headbands
| 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 |
TABLE: FDA-Approved Hair Growth Helmets
| Hair Growth Helmet Configurations | |
| Helmet Hair Growth Devices | Lights and Wavelengths |
|---|---|
| Apira iGrow | 21 laser diodes, 655 nm 30 light-emitting diodes, 655 nm red |
| Freedom Laser Therapy iRestore Essential | 82 laser diodes, 655 nm 200 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 |
Hair Growth Results
Hair density is the amount of hair per square centimeter.
The studies show that these devices significantly improved hair density in subjects’ heads.
This analysis included details on improvement for only four of the devices. I’m not sure why so much data is missing.
Below are the improvements as stated in the meta-analysis.
If the hair density result is missing here, it’s missing from the original meta-analysis.
Still, the included results are interesting, as they significantly improved hair density.
The devices re-grew hair by as much as 93.5% in these studies.
It didn’t matter which device the subjects used to get these results.
How It Works
Although the precise mechanism for red light therapy’s effect on hair growth is unknown, several robust theories exist.
Improved Blood Flow
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.
Red light therapy opens blood vessels by dislocating nitric oxide from the mitochondria to the blood vessels.
Every cell has thousands of mitochondria, which house the factories producing biological energy.
When the photons absorb in the mitochondria, they knock loose nitric oxide into the arteries.
Nitric oxide triggers dilation, making the blood vessels larger.
As a result, more blood, oxygen, and nutrition reach the hair follicles.
The theory is that the hair follicles benefit from the blood, oxygen, and nutrition supply.
Improved Adenosine Triphosphate Output
The photons knocked loose nitric oxide, inhibiting cellular energy production.
With that nitric oxide out of the way, the mitochondria make more adenosine triphosphate (ATP).
Our trillions of cells 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 to make hair.
Growth Factor Stimulation
Red light therapy enhances the 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 by promoting platelet-derived growth factor (PDGF) and transforming growth factor (TGF)²[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.
How Long It Takes
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 grows hair in only five 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.
The authors photographed the men’s hair at different points in the study. 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 significantly at week 5 of the study, continued through the 20th and final week of therapy, and 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.”
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.
The 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 men’s results were better.
Weirdly, subjects with dandruff, itchiness, or a rash before treatment started had better results.
Which Wavelengths Work
Red, infrared, blue, and ultraviolet lights 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 in growing hair in 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 substantially thicker hair shafts. The sham group had no changes.
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.
The authors photographed the men’s hair at different points in the study.
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 significantly increased 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.
Conclusion
Red light therapy is a non-invasive, safe, and effective hair growth treatment that can be used at home without a prescription.
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.
Red light therapy restores hair growth in dormant follicles.
The process works, as does Minoxidil, an FDA-approved topical treatment.
Unlike minoxidil or FDA-approved finasteride, red light therapy has no long-term or short-term side effects.
Without a prescription, the FDA has approved sports caps, headbands, laser combs, and helmets for hair regrowth at home.
If you’re ready to buy a hair growth cap, don’t do anything until you read our article about HairMax: Does HairMax Really Work? 13 Studies Say “YES”
References
[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.
[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. Epub 2021 Jun 8. PMID: 34101089.
[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/s10103-011-0953-7. Epub 2011 Jul 9. PMID: 21739260.
[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_20. PMID: 35283601; PMCID: PMC8906269.
