One day in 2020, Ronda S. Farah, MD, was spending some downtime from her dermatology practice scrolling through social media. When she opened TikTok, she came across something that piqued her interest: A popular content creator was promoting the supplement biotin as a way to grow hair. Dr. Farah was immediately alarmed, because not only was the evidence that biotin increases hair growth shoddy, but the FDA had also warned that biotin supplements may interfere with lab tests for troponin.
Dr. Farah was moved to action and made a brief TikTok stating that use of biotin does not result in hair growth for most patients, which quickly shot up to over half a million views. She was flooded with messages from influencers and people desperate for an answer to their hair growth questions.
From that point on, Dr. Farah was immersed in the world of hairfluencers, the social media personalities who promote hair care trends, which formed the basis of a review, published in the Journal of Cosmetic Dermatology that she conducted with her colleagues at the University of Minnesota, Minneapolis. .
They reviewed five treatments that represent some of the most frequently discussed hair-growth trends on social media: rosemary, onion juice, rice water, castor oil, and aloe vera. For each, they evaluated recommendations on how the treatments were applied, possible harmful effects to the user, claims that weren’t totally based on scientific evidence, and the theoretical mechanism of action. “Overall,” they concluded, “there is little to no literature supporting these social media trends for hair growth.”
Of the five, rosemary, applied to the scalp or hair, has perhaps the most significant research behind it, according to Dr. Farah and coauthors. Methods of applying rosemary described on social media included use of prepackaged oil, boiling fresh rosemary leaves, adding leaves to oils and spraying it on or massaging it on the scalp, applying it in the hair, or using it as a rinse. Dr. Farah noted that the literature supporting the use of rosemary for hair growth does not represent the most robust science; the studies had small sample sizes and used nonstandardized methods of measuring hair growth.
“It didn’t really meet rigorous, strong study methods that a board-certified dermatologist with their expertise would consider a really solid study,” she said.
For the remaining methods, there was little research to support their use for hair growth. A few, the authors pointed out, can cause scalp burns (aloe vera), damage to hair follicles (rice water), contact dermatitis (aloe vera, onion juice), and, in the case of castor oil, hair felting..
Dr. Farah thinks social media can be a great tool to reach patients, but that people should be wary of what kind of information they’re consuming “and need to be aware of who their hairfluencer is,” she said. And, as she and her coauthors wrote: “We call on dermatologists, as hair and scalp disease experts, to serve as authorities on ‘hairfluencer’ trends and appropriately counsel patients.”
The study was independently supported. Dr. Farah reports no relevant financial relationships.
A version of this article first appeared on Medscape.com.