Topical Hair Loss Treatment Linked to ED, Anxiety, and Brain Fog, FDA Warns

A prescription topical hair loss medication may cause lasting side effects that include erectile dysfunction, anxiety, and brain fog, the Food and Drug Administration warned in an April 22 alert. 

Finasteride, sold in oral form as Propecia and Proscar, is a medication that treats hair loss by preventing the body from turning testosterone into another hormone called dihydrotestosterone, or DHT.

Prescriptions for finasteride rose by 200% for men aged 25 and older over the last seven years, according to a report conducted by Epic Research on behalf of NBC News. The increase is largely driven by expanded access through telehealth companies that offer the medication as a pill or a topical spray, the report concluded.

Using finasteride is not inherently dangerous, but oral finasteride has been associated with sexual, mental, and physical side effects that persist after someone stops taking the medication—a likely rare condition called post-finasteride syndrome (PFS).

With topical finasteride, absorption “through the skin into the bloodstream is expected, and the reports describe adverse events that are consistent with those reported in association with the approved oral finasteride products,” the FDA alert said. 

According to the FDA, some people who reported side effects said they weren’t aware of the potential for them before taking topical finasteride. The agency called on health care providers to educate consumers about risks, and patients to seek out information.

“One of the problems is that these topicals are available without seeing a dermatologist,” said Ronda Farah, MD, an associate professor of dermatology at the University of Minnesota Medical School, who specializes in hair loss.

While the FDA approved Propecia and Proscar in the 1990s, the agency has not green-lit any topical form of the drug. It’s not uncommon, however, for it to be prescribed to balding patients off-label, which is legal in the United States. 

“We do things all the time off-label—use a product that is not specifically studied for, and that’s OK. But it does mean that topical finasteride has not undergone rigorous testing,” Deirdre Hooper, MD, a board-certified dermatologist at Audubon Dermatology, told Health.

Topical finasteride is made by compounding pharmacies that create alternative versions of drugs, such as ones that don’t contain certain ingredients or have different doses than are standard.

The new alert documented 32 cases of adverse events reported to the FDA regarding topical finasteride between 2019 and 2024.

Side effects included erectile dysfunction, anxiety, suicidal ideation, brain fog, depression, fatigue, insomnia, decreased libido, and testicular pain, “following the use of compounded topical products with finasteride alone or in combination with other active ingredients,” the FDA stated. 

Some people who filed the reports said they wished they had been informed about the possible side effects.

“I don’t think this is a drug that you should be able to get without speaking to a physician,” said Hooper, adding that she doesn’t prescribe topical finasteride in her practice but does sign off on oral versions. “It’s a nuanced conversation.”

Farah said the 32 reports likely underestimate how many people truly live with PFS. “Given the sheer number of people likely getting these topical treatments that’s likely a very low estimate,” she told Health.

While Hooper said the alert isn’t reason enough for people to never use topical finasteride, both she and Farah urged patients to speak to a doctor before starting the drug.

This advice applies even to people who try to get topical finasteride through a telehealth company, Hooper said, acknowledging that these services can be appealing for the many people who lack access to healthcare providers.

“I recommend against using an off-label product simply by purchasing it online. As a patient, you have to weigh risks and benefits,” Hooper said. “I would make every effort to at least have a voice-to-voice conversation with a physician before using this medication. An in-person appointment is the best choice, and a telehealth video appointment would be the second.”

Health contacted three telehealth companies that prescribe topical finasteride—Ro, Keeps, and Hims & Hers—asking for clarification about whether patients should be made aware of potential side effects and, if so, how those companies do so.

A spokesperson from Ro said the company does not have a comment regarding how they inform patients of potential side effects associated with finasteride.

At Keeps, patients are not required to have a video or telephone call with a doctor before receiving a prescription for finasteride, a company spokesperson said in an email.

But “all prescriptions, including topical finasteride, are issued only after a licensed clinician reviews a patient’s medical history and determines if the treatment is appropriate,” the spokesperson added. Providers check in with patients during their treatment, and patients can message them at any time.

Keeps also provides “clear and consistent information about potential side effects at multiple points throughout the patient experience—on our website, during the prescribing process, and in product packaging,” the spokesperson said.

At Hims & Hers, an initial video or phone appointment also isn’t required for a topical finasteride prescription, according to a company spokesperson.

Similar to Keeps, healthcare providers conduct an online evaluation and prescribe treatment if appropriate. Patients can message providers as often as needed throughout the treatment process, the spokesperson said in an email, and are given information about side effects both before treatment begins and on an ongoing basis.

Telehealth platforms have widely expanded access to finasteride in the U.S., but Hooper said it’s concerning that some don’t require patients to meet with a physician at least over the phone before starting a medication.

“These products are becoming so widely and easily available on the internet that it’s sort of, to me, as a board-certified dermatologist, frightening,” Hooper said. “That people are getting these products that are not explained face-to-face by a physician. People can just click through a questionnaire and answer questions however they want.”

According to Farah, it’s not clear what might make some people more susceptible to persistent side effects from finasteride. The lack of studies conducted on topical formulations, as well as the variation between compounded products, makes it even trickier to determine.

“We are still learning how much needs to be applied to cause a side effect like that,” Farah said. “When things are compounded, that means different pharmacies might be making it a different way. In general, the more of a drug you put on your skin, the more likely you are to have side effects.”

What’s clear, though, is that people should not downplay the potential risks associated with topical medications, Hooper said.

“You can’t forget that your skin is a massive absorber, and applying something to your skin is not without risk,” she said. “It is an organ of your body that has function and structure.”