Finasteride, first used to treat prostate enlargement, has become the president’s choice to combat hair loss.

BY SARAH WATTS – Daily Beast

Two weeks ago, White House physician Ronny Jackson issued a highly anticipated statement on President Donald Trump’s health following a complete physical exam. Trump, Jackson claimed, is in “excellent health” with no concern of physical or cognitive decline.

Jackson also revealed that, in addition to cholesterol medication and a multivitamin, the president pops the oral supplement finasteride (often sold as the brands Propecia, Propecia Pro-Pak, and Proscar) to treat male-pattern baldness. While the use of finasteride to help prevent male-pattern baldness is not new—it was first approved for treating prostate enlargement in 1992 before being rebranded and sold in 1997 as a hair-loss drug—it has come under fire in recent years for its supposed extreme side effects. In 2015, Merck, the drug’s manufacturer, was hit with multiple class-action lawsuits alleging the drug caused severe sexual and emotional side effects.

According to Dr. Nikki Hill, a board-certified dermatologist and hair-loss specialist based in Tucker, Georgia, using finasteride in FDA-approved doses (1 milligram) is not harmful for the vast majority of her patients.

“About 2 percent of men in their twenties have sexual side effects,” Hill told The Daily Beast. Occasionally, Hill’s patients will report decreased sperm volume after taking the drug and sometimes even bouts of depression—but that side effect is thankfully rare, Hill says. “I’ve had maybe three people in six years tell me that they feel a little more depressed, but they don’t know if it’s circumstantial or due to taking the medicine. I end up taking them off it [if they report depression] just to make sure.” The FDA lists depression as a possible side effect of finasteride on its website (PDF).

Finasteride works by blocking an enzyme that converts testosterone to dihydrotestosterone, or DHT. Paradoxically, DHT is the hormone responsible for sexual function and hair growth earlier in life. But as men age and their testosterone decreases, an imbalance of testosterone and DHT can actually cause hair follicles to shrink, inhibiting new hair growth.

In the past few years, however, a growing number of patients are reporting severe neurological side effects after taking finasteride‚ so many that the National Institutes of Health (NIH) recognizes Post-Finasteride Syndrome on their list of genetic and rare diseases. Patients suffering from so-called Post-Finasteride Syndrome have reported mental and neurological side effects, like depression, suicidal ideation, anxiety, and impaired memory, and have reported such symptoms even after several months of discontinuing the drug. But these claims make little sense to most dermatologists.

“Finasteride has a very short half-life,” said Dr. Nicole Rogers, a board-certified dermatologist and assistant clinical professor of dermatology at Tulane University. “The drug is fully metabolized within a week, so for people with Post-Finasteride Syndrome to be reporting decreased libido and brain fog, and having it continue despite stopping the drug—from a neurological perspective, we don’t really understand why that would be.”

According to Rogers, finasteride is one of the most potent drugs on the market, and only one of two FDA-approved methods for hair loss (minoxidil, or Rogaine, being the other). While Rogaine needs to be applied to the hairline topically, finasteride is generally taken as an oral medication, which patients prefer since Rogaine can leave them looking greasy. What’s more, finasteride is typically much more effective. “It can be a miracle medicine for people who take it,” said Rogers, though she cautions that if patients are already prone to anxiety, depression, or have a family history of erectile dysfunction, this may not be the treatment for them.

In addition to possible sexual and neurological side effects, increasing the risk of high-grade prostate cancer may also be a concern.

“Nobody who has a strong family history of prostate cancer should go on this medicine,” Hill said. “And if they do, they need to be closely monitored.” According to Hill, doctors are able to screen patients for prostate cancer by checking the level of a chemical called PSA, or prostate-specific antigen, in the bloodstream. Finasteride, however, has been shown to artificially lower the number—even when prostate cancer is present.

“If you’re taking finasteride, let your doctor know, and have digital rectal exams to assess prostate cancer, rather than a blood test,” Hill suggested. “If there’s a family history of prostate cancer in my patients, I find other alternatives [to finasteride] because they’ll be tested at a younger age, and their PSA levels are very important.”