Study shows promise; real-world tests remain rare

caffeineReal-world tests of the efficacy of caffeine-containing shampoos and lotions are rare. Photo: Getty Images By Laura Johannes

Updated April 25, 2016 11:35 a.m. ET

Many men struggle with baldness and wonder about new treatments. Some shampoos and lotions contain caffeine and promise to help keep hair thick and full. How does the evidence stack up?

A 2014 study found that caffeine has a “potent” effect in growing hair in laboratory conditions. But real-world tests of the efficacy of caffeine-containing shampoos and lotions are rare, and those that have been done show a modest effect.

The laboratory work sounds “really promising. But in terms of clinical application we’re not there yet,” says Tina Alster, a clinical professor of dermatology at Georgetown University in Washington, D.C. More rigorously designed studies in humans are needed, she says.

Androgenetic alopecia, which can affect both men and women, is hair loss caused as testosterone shortens the hair follicle’s growth cycle, resulting in progressively shorter, finer hair, says Ingrid Roseborough, a clinical instructor at the department of dermatology at the University of California, San Francisco.

In the 2014 study published in British Journal of Dermatology, a team of academic researchers found that small concentrations of caffeine, applied to hair follicles extracted from human males and grown in a lab, counteracted the effects of testosterone, stimulating hair growth and prolonging the time the hair follicles remained in their growth phase. The study found the caffeine also had a beneficial effect on female hair growth, but only when used in an even more diluted form than was used for male hair follicles.

alpecinDr. Kurt Wolff’s Alpecin Caffeine Shampoo. Photo: Dr. Kurt Wolff

Earlier research by the same scientists found that higher concentrations of caffeine can actually suppress hair growth in men and women. This could be because the caffeine overstimulated the hair follicle, the researchers suggested. “It’s hard to predict exactly how much is too much of this agent. We just don’t have the information,” says Dr. Roseborough, who was not involved in the study. She noted that the lab experiment was done over just a few days, so it isn’t clear it will translate to long-term results in humans.

Caffeine-containing products that hit the U.S. market in recent years include Dove Men+Care Thick & Strong Fortifying 2 in 1 Shampoo + Conditioner, about $4 to $5 for 12 ounces from London’s Unilever PLC, and Hair Surge, $43.99 for eight ounces, from Ultrax Developments Corp. in Phoenix. In addition to caffeine, Hair Surge has other hair-thickening ingredients, says Kyle Uchitel, Ultrax co-owner.

Neither company has published studies on the products, but Alpecin Caffeine Shampoo C1 from family-owned business Dr. Kurt Wolff GmbH & Co. KG in Bielefeld, Germany, has been tested in studies published in 2010 and 2013 in the Journal of Applied Cosmetology. Alpecin Caffeine Liquid, which was designed to be applied after washing and can be used in conjunction with the shampoo or alone, was tested in a 2011 study.

There was “a little bit” of hair regrowth seen in the studies, “but it does not mean your hair will grow like when you were 20 years old,” says dermatologist Leonard Celleno, a researcher at Catholic University of the Sacred Heart in Rome. It’s possible the products could have an additive effect if used in conjunction with other hair-growth products, such as minoxidil, but the Sacred Heart studies didn’t test that, he adds. The studies were funded by the company.

Dr. Kurt Wolff GmbH plans to begin selling Alpecin shampoo and liquid in the U.S. this summer, says Theresa Ladleif, product manager. The price has not yet been set. The products can be used in males from puberty, to begin counteracting the effects of testosterone on hair follicles as soon as possible, she says.

While the Alpecin products are designed for men, they can be used by women, particularly after menopause when hormone balance begins to change, she adds.

Write to Laura Johannes at aches@wsj.com