Finasteride Side Effects: What The Label Says And What To Watch For
Finasteride is one of the main treatments for male pattern hair loss, and also the one men worry about most. Most of that worry is about sexual side effects. Here is what the FDA label actually reports, what is less common, and what to watch for.
Sexual Side Effects: What The Trials Found
In the 12-month placebo-controlled trials described in the labeling for Propecia® (finasteride 1 mg), lower sex drive, erection problems, and changes in ejaculation were each reported by fewer than 2 in 100 men taking finasteride, slightly more often than in men taking a placebo. The label notes these resolved in men who stopped the drug, and in most men who kept taking it.
When Side Effects Don’t Go Away
Since approval, the label has added reports from real-world use of sexual problems that continued after men stopped finasteride, including erection, libido, ejaculation, and orgasm problems, as well as male infertility and poor semen quality. Because these reports are voluntary, they can’t show how often this happens or prove finasteride caused it. If you are trying to conceive, or this risk weighs on you, raise it with your provider before starting, and tell them early if anything changes.
Mood Changes
The label also lists depression and suicidal thoughts among reports from real-world use. Pay attention to your mood after starting, and contact your provider promptly if you notice depression or any thoughts of harming yourself. If you are in crisis, call or text 988 to reach the Suicide & Crisis Lifeline.
Effects On PSA And The Prostate
Finasteride lowers PSA, the blood test used in prostate cancer screening, by about half. The label says a PSA measured after six months or more on finasteride should be doubled before comparing it with normal ranges, so make sure whoever orders your PSA knows you take it. Drugs in this class, 5-alpha reductase inhibitors, also carry a label warning about an increased risk of high-grade prostate cancer, based on large trials of higher-dose versions.
Other Things On The Label
Breast tenderness or enlargement has been reported, and so has male breast cancer, so tell a provider about any breast lump, pain, or nipple discharge. Allergic reactions such as rash, hives, or swelling of the lips or face need prompt care. Finasteride is not for women or children, and women who are or may become pregnant shouldn’t handle crushed or broken tablets, because it can harm a male fetus.
It also takes patience. The label says three months or more of daily use is needed before benefit shows, and that stopping reverses the effect within 12 months. Our guide to finasteride vs. minoxidil covers how it fits alongside other options.
Where To Start
Osirius offers finasteride tablets and a compounded topical that combines minoxidil, finasteride, and retinoic acid. Compounded medications are not FDA-approved and have not been evaluated by the FDA for safety or effectiveness, and the label figures above come from studies of the 1 mg tablet, not a topical. A licensed provider reviews your history and decides which option, if any, fits.
This guide explains general information and is not medical advice. It doesn't replace a licensed provider reviewing your own history.