As Finasteride Use Surges Among Younger Men, Doctors Warn of Rare Side Effects

An increasing number of young men are taking finasteride to prevent hair loss, raising concerns about rare but potentially long-lasting side effects.

According to a report by Epic Research for NBC News, finasteride prescriptions among U.S. men have surged nearly 200% in the past seven years.

“It’s like water in my clinic,” says Dr. Jerry Shapiro, a dermatologist at NYU Langone Health. “I’m prescribing it all the time.”

Although the Epic report focused on men aged 25 and older, Shapiro and other doctors are seeing a trend of even younger men, some in their late teens, seeking treatment to preempt hair loss.

Telemedicine companies like Hims, Keeps, and Ro, which heavily advertise the drug, may partly explain the rise in prescriptions, says Dr. Maria Colavincenzo, a dermatology associate professor at Northwestern Feinberg School of Medicine.

Social media influencers and popular Reddit communities like “tressless” also promote finasteride for hair loss and regrowth, leading more young men to consider early treatment.

Doctors assert that the daily pill is safe, but it requires ongoing use to maintain its effects. However, the drug is controversial due to the risk of impotence, which may persist even after discontinuing the medication.

What is finasteride, and does it work?

Originally developed to treat an enlarged prostate, finasteride, branded as Propecia, has been FDA-approved for hair loss for nearly 30 years. The daily pill combats androgenetic alopecia, or male-pattern baldness, which affects about half of men by age 50.

While there’s no conclusive proof that starting finasteride early guarantees lifelong hair retention, doctors suggest it lowers the risk of baldness. Finasteride works by blocking the 5-alpha reductase enzyme, preventing the conversion of testosterone to dihydrotestosterone (DHT), which is believed to shrink scalp hair follicles and shorten the hair growth cycle.

Blocking this enzyme halts the shrinkage of hair follicles, potentially reversing it to some extent, says Colavincenzo. Genetics play a significant role in individual responses to DHT, making it an active area of research.

Most men taking finasteride successfully slow their hair loss. Studies indicate an 80% to 90% success rate in preventing further hair loss, according to Shapiro. The drug is more effective at prevention, so earlier use is better, but it requires lifelong commitment.

“Most things in medicine are lifelong,” Shapiro notes, comparing it to chronic conditions like high cholesterol or blood pressure requiring continuous medication.

Dr. Carolyn Goh, a dermatologist at UCLA Health, acknowledges limited long-term efficacy data but affirms that the drug’s benefits persist over time. A Korean study found that nearly 100% of men had the same or more hair after five years of finasteride use. An Italian study reported that 86% of men experienced no hair loss after ten years of use.

While finasteride excels at preventing further hair loss, it is less effective at regrowing lost hair, often leading to combined treatment with minoxidil, a topical growth stimulant.

Despite its success, patients may not always notice its effectiveness, Colavincenzo says. “Even if your hair is just not getting worse, it’s a success.”

Since male-pattern baldness is considered cosmetic, finasteride is rarely covered by insurance. Available generically since 2006, it typically costs less than $100 per month.

What are finasteride’s side effects?

In 2022, after pressure from a patient advocacy group, the FDA required warnings about potential suicidal behavior in men taking finasteride. A 2023 article in the International Journal of Impotence Research further ignited debate over post-finasteride syndrome, associated with decreased libido, erectile dysfunction, and cognitive issues.

Common side effects include decreased sex drive, erectile difficulties, and reduced semen volume, typically affecting fewer than 5% of men on the drug. There are also concerns about mental health effects, including depression, though the frequency and causality are unclear.

“The vast majority of my patients have no such side effects and do well with it,” says Colavincenzo. She advises against the medication for men already experiencing sexual issues.

Shapiro emphasizes the rarity of permanent side effects. “I’ve never seen it in a patient, and I’ve treated thousands of patients,” he says.