Women may end up paying more than men at their local store for the same hair loss medicine, suggests a new study.
Minoxidil - known by the popular brand name Rogaine - was 40 per cent more expensive when it was marketed as a foam to women than when it was advertised to men, researchers found.
"Ethically it seems pretty questionable to be charging women more for the same thing," said senior author Dr. Jules Lipoff, of the University of Pennsylvania's Perelman School of Medicine in Philadelphia.
Lipoff said a trip to a store led to the study, because he noticed the listed price per ounce for minoxidil was more for the box marked for women than the box marked for men.
The drug is used to treat male- and female-pattern hair loss, which affects 80 million people in the United States, the researchers write in JAMA Dermatology.
Minoxidil is available over the counter as a 5 per cent solution for men and a 2 per cent solution for women - both to be used twice per day. In 2006, the US Food and Drug Administration approved a 5 per cent foam version of the medicine for men to be used twice per day. The agency approved the same foam for women in 2014 for use once per day.
For the new study, the researchers collected 41 minoxidil products between July and November 2016 from the nation's largest retail chains in Indiana, Ohio, New York and Pennsylvania. Those chains were CVS, Kroger, Rite Aid, Target, Walgreens and Walmart.
The prices of minoxidil solution and foam were compared per 30 milliliters of the product.
The price per 30 ml of 2 per cent solution for women averaged to $7.61, compared to $7.63 per 30 ml of 5 per cent solution for men.
While the difference in price per 30 ml of solution was not statistically significant between the male and female products, Lipoff pointed out that it could still be interpreted as women paying more for the medicine. After all, he said, women are paying the same price for less than half of the active ingredient found in the solution marketed to men.
There is a possibility that the added inactive ingredients in the women's solution leads to a more costly product, he said. The argument can't be made for the 5 per cent foam, though, because the product advertised to men is identical to the product marketed to women.
Yet, the price per 30 ml of 5 per cent minoxidil foam was $11.27 for the product marketed to women, compared to $8.05 for the product marketed to men.
Minoxidil is currently only sold as a foam under the brand name Rogaine by Johnson and Johnson Consumer Inc.
A spokesperson for the company said Men's Rogaine Unscented Foam and Women's Rogaine Unscented Foam are priced the same on its website, but he could not speak for the prices of individual retailers.
Lipoff told Reuters Health that most dermatologists he knows recommend people only use the foam version of minoxidil marketed to men because of the price difference.
"I tell all of my patients that I'm treating for hairloss to not buy Women's Rogaine," he said. "I explain to them that it's the same product, but you pay more because you're a woman."