Does Red Light Therapy Help Hair Growth? Evidence, Benefits & Results

Red light therapy has been tested against placebo devices in randomized clinical trials for hair growth. A systematic review and meta-analysis[1] suggests it can benefit people with certain pattern hair loss, although results could vary between individuals.

 

What is Red Light Therapy for Hair?

Red light therapy for hair is often called photobiomodulation[2] or low-level laser therapy (LLLT). It uses red and near-infrared light aimed at the scalp; typically somewhere in the 600-850 nm range. This light is not hot, and it does not burn or tan. It is a non-invasive method and works at intensities low enough that scalp tissue does not heat up. 

FUN FACT: Red light therapy is a 60-year-old accidental discovery by researcher Endre Mester, who was attempting to see if red laser light would cause cancer in mice, but instead it accelerated hair growth and wound healing in mice.[3] 

 

Why does light do anything to hair at all?

Hair loss is not caused by a shortage of light. So, the obvious question is: why should shining light on a scalp change anything?

 

Not all tissues respond to light. For a tissue to undergo a biological change via light therapy, it needs a molecule that can ‘accept’ photons. These photo-acceptors are present in various tissues, including eyes, blood vessels, nerves, skin, and hair. Hair contains photoreceptors, probably around the middle of the follicle where regenerative cells are found.

How Does Red Light Therapy Work on Hair Follicles?

Mitochondria are the energy-producing part of our cells. In the hair follicle, the mitochondrial enzyme called cytochrome c oxidase absorbs the photons of red and infrared light and boosts ATP production.[4] ATP is the cell’s usable energy currency and supports the struggling hair follicle growth through various paths.

· It may help encourage follicles to enter the active growth phase from dormancy. [5]

· It increases blood flow to the scalp by increasing nitric oxide release, bringing more oxygen and nutrients to the follicle.

· It reduces localized inflammation around the follicle, a known contributor to follicle miniaturization in pattern hair loss.  

However, it is important to know that RLT only works on follicles that are still alive but underperforming[5], have thin-hair-producing follicles, or have early-to-moderate pattern hair loss. But if a follicle has already died, no amount of light will bring it back.

What is the Clinical Evidence?

Laser light therapy for hair growth has been shown effective in multiple controlled trials and reviews, with consistent results across FDA-cleared devices for androgenetic alopecia in men and women.

Devices vs Placebo: In a widely cited meta-analysis[6], two groups, including men and women, were tested; one group was treated with RLT, and the other with placebo devices. It indicates a significant increase in hair density, with a standardized mean difference of 1.27 -a highly noticeable effect compared to the control group.

Hair Density in Men and Women: In a separate 1-year-long prospective study, researchers evaluated a red light-emitting light therapy helmet-style device on 68 patients, 51 men and 17 women[6].  After 48 weeks of using the device three times a week, participants experienced a noticeable increase in hair density from a baseline of roughly 99 hairs per square centimeter to about 124 hairs per square centimeter.

Androgenic Alopecia in Women: Another 16-week study focused[7] on women experiencing androgenic alopecia (pattern hair loss) who used a comparable at-home helmet device. It measured changes with standardized scalp photography and showed a significant effect on increasing hair density with no adverse effects.

 

Conclusively, these studies suggest that consistent use for several months may be important for achieving measurable improvements. RLT for hair growth can take months, not days, and requires sticking to a schedule.  

Who Does Red Light Therapy Work for and Who it Doesn’t ?

The first question in mind is always, “Is it for everyone?” The answer is simple: as shown in the studies above, it suggests that it may increase hair density and hair growth in people with androgenic alopecia, which is a genetic, hormone-driven thinning of hair in men (usually at the crown) and women (usually diffuse thinning at a part).

It is not recommended for autoimmune hair loss like alopecia areata, scarring alopecias, or shedding caused by any nutritional deficiencies, thyroid issues, or medications. If you are not sure which kind of hair loss you have, that is worth a conversation with a physician or dermatologist before buying anything.

How to Choose a Red Light Therapy Device for Hair Growth?

Not all red light devices perform the same way.[6] What matters most:

Wavelength: Look for the range used in the trials. Be skeptical of devices marketed for hair growth based on wavelengths that were not tested for the scalp. There is good data that hair responds to light in one of these four wavelength ranges.

614-624 nm 

668-684 nm

751-772 nm

813-846 nm

Dose, not diode count: The useful specifications are irradiance (mW/cm²) and total dose (J/cm²), not how many lights are on the box.

Coverage: Light only works where it lands. A device that leaves gaps over the areas you care about will underdeliver regardless of its specifications. Some manufacturers, including LifeZoom, use a flexible, curved panel design that shapes to the scalp for more even light contact, addressing one of the common limitations of flat panel devices.

More is not better: Photobiomodulation has a biphasic dose response: too little light does nothing, and exceeding the recommended session time can blunt the effect rather than boost it. Whatever device you choose, always remember to read the guidance on session length and distance from the scalp.

One reason people give up is overdosing before RLT gets a fair chance to work, which is why LifeZoom backs the device with a 30-day trial period and an extended warranty, so there’s room to test whether it fits your routine before committing long-term.

 

A Chance to Not Only Regain Your Hair but Also Your Confidence!

While red light therapy does not work for every type of hair loss, it may give people with androgenetic alopecia a non-invasive option to not only regain their hair but also their confidence. While it has evidence-based and FDA-cleared devices, which puts it into a different category than other over-the-counter hair growth claims, it should not be viewed as a cure.

All you need is to choose a well-designed device, consistency, a schedule, and consult a healthcare professional when appropriate to set realistic expectations.

 

References

1. Lueangarun, S., Visutjindaporn, P., Parcharoen, Y., Jamparuang, P., & Tempark, T. (2021). A systematic review and meta-analysis of randomized controlled trials of United States Food and Drug Administration-approved, home-use, low-level light/laser therapy devices for pattern hair loss: Device design and technology. The Journal of Clinical and Aesthetic Dermatology, 14(11), E64–E75.

2. Dompe, C., Moncrieff, L., Matys, J., Grzech-Leśniak, K., Kocherova, I., Bryja, A., Bruska, M., Dominiak, M., Mozdziak, P., Skiba, T. H. I., Shibli, J. A., Volponi, A. A., Kempisty, B., & Dyszkiewicz-Konwińska, M. (2020). Photobiomodulation—Underlying mechanism and clinical applications. Journal of Clinical Medicine, 9(6), 1724. https://doi.org/10.3390/jcm9061724

3. Lanzafame RJ, Blanche RR, Chiacchierini RP, Kazmirek ER, Sklar JA. The growth of human scalp hair in females using visible red light laser and LED sources. Lasers Surg Med. 2014 Oct;46(8):601–7. doi:10.1002/lsm.22277 PubMed PMID: 25124964; PubMed Central PMCID: PMC4265291.

4. Hamblin MR. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophys. 2017;4(3):337–61. doi:10.3934/biophy.2017.3.337 PubMed PMID: 28748217; PubMed Central PMCID: PMC5523874

5. Avci P, Gupta GK, Clark J, Wikonkal N, Hamblin MR. Low-level laser (light) therapy (LLLT) for treatment of hair loss. Lasers Surg Med. 2014 Feb;46(2):144–51. doi:10.1002/lsm.22170 PubMed PMID: 23970445; PubMed Central PMCID: PMC3944668.

6. LUEANGARUN S, VISUTJINDAPORN P, PARCHAROEN Y, et al. A systematic review and meta-analysis of randomized controlled trials of United States Food and Drug Administration-approved, home-use, low-level light/laser therapy devices for pattern hair loss: Device design and technology[J]. The Journal of Clinical and Aesthetic Dermatology, 2021, 14(11): E64-E75.

7. Yoon JS, Ku WY, Lee JH, Ahn HC. Low-level light therapy using a helmet-type device for the treatment of androgenetic alopecia. Medicine (Baltimore). 2020 Jul 17;99(29):e21181. doi:10.1097/MD.0000000000021181 PubMed PMID: 32702878; PubMed Central PMCID: PMC7373546.