Topical melatonin improves scalp hair growth, density in androgenetic alopecia

Key takeaways:

• Melatonin bested controls in terms of scalp hair growth in individuals with androgenetic alopecia.
• Optimal dosing for this intervention appears to be 0.0033% or 0.1% applied once daily for 90 to 180 days.

Patients with androgenetic alopecia demonstrated improvements in hair follicle growth and density after treatment with topical melatonin, according to a study.

“Melatonin, a pleiotropic hormone, affects the physiological processes including that of the hair follicle,” Arash Babadjouni, MS, of the department of dermatology at the University of California, Irvine, and of Midwestern University Arizona College of Osteopathic Medicine, and colleagues wrote. “We seek to identify the scientific evidence to support the potential benefits of melatonin in human hair growth.”

The researchers reviewed PubMed, Google Scholar and Cochrane databases for studies investigating associations between melatonin and hair loss through 2022. The team included two independent reviewers that evaluated the data sets for inclusion criteria. Demographics underwent assessment, as did the type of melatonin intervention, study type and, ultimately, the impacts on hair.

Eleven studies which detailed evidence of melatonin use in patients with alopecia were included. Overall, data for 2,267 patients — including 1,140 men — made the final analysis.

Results showed that eight studies demonstrated positive outcomes for patients with androgenetic alopecia who were treated with topical melatonin.

In addition, eight studies also showed an improvement in scalp hair growth with melatonin treatment, whereas four studies demonstrated that melatonin improved scalp hair density compared with controls. An additional two studies showed that melatonin bested controls in terms of hair shaft thickness.

The range for an optimal melatonin dose may be 0.0033% or 0.1% applied as a once-daily regimen for a duration of 90 to 180 days. Additionally, optimizing the vehicle for topical melatonin — for example, with nanostructured lipid carriers — may further improve the hormone’s impact on hair growth.

The researchers also noted that a 1.5 mg twice-daily oral dose for 180 days may also have utility, but said there was “limited evidence” for this dosage.

“There is evidence to support melatonin use to facilitate scalp hair growth, particularly in men with AGA,” the researchers concluded.

They added that future research should explore the mechanism of action of this benefit.