December 09, 2019
4 min read

BLOG: ‘Robust’ data support red LED light therapy for hair growth

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by Rodney Sinclair, MD

Androgenetic alopecia is the most common type of hair loss, affecting an estimated 50 million men and 30 million women in the U.S. Men with androgenetic alopecia, also known as male-pattern hair loss, experience a receding hairline or balding of the crown, and women have overall thinning or widening of the midline.

Rodney Sinclair, MD
Rodney Sinclair

FDA-approved pharmaceuticals include topical minoxidil and oral finasteride labeled for use in men. Device-based treatments cleared by FDA to treat hair loss include low-level laser therapy (LLLT) and Revian Red dual wavelength LED light therapy (PhotonMD).

Revian Red is a new class of modulated light therapy that uniquely relies on two colors of LED. The red LED set at 660 nm stimulates hair growth via the classic pathway while the 620 nm LED stimulates release of nitric oxide. The device’s high output dual wavelength LEDs provide broad scalp coverage and better skin penetration than the earlier models of LLLT.

During the past 25 years, I have treated more than 15,000 men and women with hair loss. I have actively researched the genetics of baldness, the molecular mechanism of hair loss and conducted clinical trials to test new and emerging treatments for hair loss. These trials have included both finasteride and minoxidil when they were emerging treatments, as well as a number of other therapies that failed or have not yet come to market.

From time to time, I am called as an expert witness in court cases. One case, about 15 years ago, involved a patient having laser hair removal that not only failed to remove the unwanted hair on his back, but paradoxically resulted in increased hair growth. The patient was unhappy and wanted to sue.

It turned out that these older hair removal lasers were underpowered and when used on low settings had the reverse effect of actually stimulating hair growth in some patients. As news of these paradoxical reactions to hair removal laser got out, researchers started to experiment with lower laser settings to make hair grow.

Because an LLLT device is FDA cleared does not mean it actually works. The FDA marketing pathway for devices is very different compared with the pathway for drugs, with the bar for the former being set much lower. In fact, the first LLLT approved by the FDA was universally disappointing from a patient perspective, promising much but delivering little in terms of hair regrowth.


Today, 15 years later, laser hair loss treatments have stuck around, with some products having moderate efficacy yet not generating sufficient hair regrowth to truly catch on. One true “survivor” is the laser cap concept, a technology that has evolved and gained loyal users. There is peer-reviewed clinical evidence published to confirm that red light grows hair. Commonly used LLLT products include the iGrow, TheraDome, illumiflow, iRestore, Capillus and HairMax. All of these devices are FDA cleared, and all have varying degrees of evidence to support their use. None, however, has been a standout. This makes it difficult for consumers not only to choose the most effective LLLT device, but also to know how often to use it, for how long, and what results to expect.

Clinical efficacy, pharmaceutical-like rigor

To take the next step and put red light technology to the test in a way that could be interpreted by potential patients as meaningful, the manufacturers of Revian Red laser cap designed a clinical trial similar to that required for a pharmaceutical product. This would also allow a direct comparison to FDA-approved drugs like minoxidil and finasteride. PhotonMD demonstrated real leadership in the space when the company engaged me to design a protocol to test its technology properly. I worked to ensure the trial was sufficiently rigorous, and that we had sufficient patient volunteers to power clinically meaningful results with statistical significance.

It is important to note that the trial tested one specific product and one specific schedule of use — 10 minutes once a day for 6 months. We did not evaluate the concept of LLLT, and so our data are not extrapolatable to any other device or protocol. An important strength of this study was the ability to electronically monitor participants’ use of the cap to ensure compliance and maintain the trial’s integrity. The Revian Red system is controlled by a mobile phone app that shows treatment compliance and creates an interface for users to track their progress.

Top-line results

Adult men and women with androgenetic alopecia were randomly assigned in a double-blind fashion to a light-based hair growth treatment or placebo cap worn for 10 minutes per day for up to 26 weeks. The participants stopped all other hair growth aids before enrolling in the study. The primary endpoint was the hair count of a 1 cm2 target area at week 16. Among the evaluable patients who completed the study per protocol (ie, those at least 80% compliant), the 18 assigned to red light therapy regrew an average of 21.3 additional hairs/cm2 compared with their baseline. In contrast, the 18 participants randomly assigned to wear the placebo cap continued to lose hair throughout the duration of the study. There were no treatment discontinuations due to an adverse event and no device-related serious adverse events.

To offer patients the most effective and up-to-date solutions, it is imperative we provide them with robust data to support our recommendations. The Revian Red system is an example of a device-based approach that has been proven to work when examined under a randomized, double-blind, placebo-controlled protocol identical to that used in pharmaceutical testing. In all conscience, I could not recommend any other LLLT devices until they were able to provide data of similar quality.


For more information:

Rodney Sinclair, MD, is principal of Sinclair Dermatology with practices in East Melbourne and Pascoe Vale, Australia. He is the professor of dermatology at the University of Melbourne and the director of Epworth Dermatology. He is past president of the Australasian Society for Dermatology Research, the Australasian Hair and Wool Research Society and the Skin and Cancer Foundation of Victoria. Email:


Disclosure: Sinclair reports he is principal investigator in the trial mentioned herein and is a director of Samson Clinical that holds patents on the use of oral minoxidil in the treatment of hair loss. Other financial disclosures include AbbVie, Amgen, Ascend, Bayer, Boehringer Ingelheim, Botanix, Celgene, Coherus Biosciences, Cutanea, Eli Lilly and Co., Galderma, GlaxoSmithKline, Janssen, Leo Pharma, MedImmune, Merck & Co., MSD, Novartis, Oncobiologics, Pfizer, PhotonMD, Principia, Roche, Regeneron, Samson Clinical and Sun Pharma.