because of small sample sizes, heterogeneity of hair loss types in study subjects, or other limitations.
The review, published online in JAMA Dermatology, notes that “Twelve of the 20 nutritional interventions had high-quality studies suggesting objectively evaluated effectiveness.”
It is “ground breaking,” in part because of its breadth and depth, said Eva Simmons-O’Brien, MD, a dermatologist in Towson, Md., who often recommends supplements for her patients with hair loss. “It basically kind of vindicates what some of us have been doing for a number of years in terms of treating hair loss,” she told this news organization. “It should hopefully make it more commonplace for dermatologists to consider using nutritional supplements as an adjuvant to treating hair loss,” added Dr. Simmons-O’Brien.
The review “is very helpful,” agreed Lynne J. Goldberg, MD, professor of dermatology and pathology and laboratory medicine at Boston University. Dr. Goldberg noted that many patients are already taking supplements and want to know whether they are safe and effective. The review “points out what the problems are; it talks about what the individual ingredients are and what they do, what the problems are; and it concluded that some people may find these helpful. Which is exactly what I tell my patients,” said Dr. Goldberg, who is also director of the Hair Clinic at Boston Medical Center.
Dr. Arash Mostaghimi
“For patients who are highly motivated and eager to try this, we’re hoping that this systematic review serves as a foundation to have a conversation,” study coauthor Arash Mostaghimi, MD, MPA, MPH, of the department of dermatology at Harvard Medical School, told this news organization. “When there’s medical uncertainty and the question is how much risk is one willing to take, the most important thing to do is to present the data and engage in shared decision-making with the patient,” noted Dr. Mostaghimi, who is also director of the inpatient dermatology consult service at Brigham and Women’s Hospital, Boston.
Surprising effectiveness
Going into the study, “we felt it would be likely that majority of nutritional supplements would either not be effective or not studied,” he said.
Dr. Mostaghimi and his coauthors conducted the study because so many patients take nutritional supplements to address hair loss, he said. An initial literature survey yielded more than 6,300 citations, but after screening and reviews, the authors included 30 articles for evaluation.
The review begins with a look at studies of saw palmetto (Serenoa repens), a botanical compound thought to inhibit the enzyme 5-alpha reductase (5AR), which converts testosterone to dihydroxytestosterone (DHT). DHT is a mediator of androgenic alopecia (AGA). The studies suggest that the compound might stabilize hair loss, “although its effect is likely less than that of finasteride,” write the authors. They also note that side effects associated with finasteride, such as sexual dysfunction, were also observed with saw palmetto “but to a lesser extent.”
For AGA, pumpkin seed oil may also be effective and a “potential alternative” to finasteride for AGA, and Forti5, a nutritional supplement that includes botanical 5AR inhibitors and other ingredients, had favorable effects in one study, the authors write. But neither has been compared to finasteride, and the Forti5 study lacked a control group.
The review also examines the micronutrients vitamin D, zinc, B vitamins, and antioxidants. Low levels of vitamin D have been associated with alopecia areata (AA), AGA, and telogen effluvium (TE) in some studies, and zinc deficiencies have been associated with TE, hair breakage, and thinning, according to the review. A single-arm vitamin D study showed improved results at 6 months for women with TE, but there was no control group and TE is self-resolving, the authors add. Studies in patients with normal zinc levels at baseline who had AA or hair loss showed significant hair regrowth and increased hair thickness and density, but the trials were a mishmash of controls and no controls and relied on self-perceived hair-loss data.
Larger more rigorous studies should be done to evaluate zinc’s effectiveness with AA, the authors comment.
Dr. Eva Simmons-O'Brien
Many patients take vitamin B7 (biotin) for hair loss. It has not been studied on its own but was an ingredient in some supplements in the review. Dr. Simmons-O’Brien said that biotin won’t result in new hair growth but that it can help strengthen the new hairs that grow as a result of other therapies. Both she and the study authors note that the Food and Drug Administration has warned against biotin supplementation because it can interfere with troponin and other test results.
The review also finds that immunomodulators –such as Chinese herbal extracts from paeony and glycyrrhizin – were effective in severe AA. Growth hormone modulators targeting deficiencies in insulin growth factor 1 or growth hormone are also promising. Studies of the modulators capsaicin and isoflavones – used topically – spurred hair growth, the authors write.
Products containing marine protein supplements, including Viviscal and Nourkrin, appeared effective in increasing hair counts in men and women, but the studies were funded by the manufacturer and were not well controlled. Side effects with Viviscal included bloating, according to the review.
The multi-ingredient supplements Nutrafol, Omni-Three, Apple Nutraceutical, and Lambdapil were also included in the review. Only Omni-Three showed no effectiveness, but studies of the other supplements had various limitations, including lack of controls and small sample sizes.