Finasteride is a DHT-blocking prescription medication used to treat male pattern hair loss. You might know better by its brand names, Propecia or Proscar.

There are a lot of rumors out there about this drug and its side effects. Being curious—or even concerned—about finasteride’s side effects is completely fair. Before you take any medication (or really make any decisions involving your own healthcare), you should always do your research and make sure you’re comfortable with your treatment plan. To make that easier for you, we went ahead and summed up the important facts below.

If you’d rather watch than read, check out this quick explainer from hair loss expert Dr. Jerry Shapiro:

Finasteride’s side effects

Yes, like any drug, there might be side effects. Some of the possible side effects of taking finasteride 1mg include:

  • dizziness
  • weakness
  • feeling like you might pass out
  • headache
  • runny nose
  • rash
  • swelling in your hands or feet
  • swelling or tenderness in your breasts
  • impotence
  • decreased sex drive
  • decreased semen volume
  • depression

Finasteride’s sexual side effects

Let’s just jump right into what’s likely your biggest fear though: erectile dysfunction. Or, more specifically, the fear that taking finasteride will disrupt your sex life.

Though rare, in clinical trials, 3.8% of male patients noticed some form of sexual side effects (versus 2.1% of patients using the placebo), including less desire for sex, difficulty in achieving an erection, or a decrease in the amount of semen released during sex. This may continue after stopping treatment.

The number to focus on there is 3.8%. It’s small. Now, that’s not to diminish your concern or to say that the 3.8% people experiencing these symptoms don’t matter—but rather to point out that this isn’t a guaranteed side effect of taking finasteride. Despite what you may hear, for 96% of men, taking this common hair loss medication doesn’t mean you have to choose between your sex life and your hairline. Plus, it’s important to note that 2.1% of men using the placebo experienced the same side effects.

Now, you might be wondering what happens if you’re part of that 3.8% who experiences side effects. You might’ve even heard about post-finasteride syndrome, non-medical term used to describe a variety of long-term side effects reported by a small number of men even after they stopped taking the medication.

Well, the good news is that hair loss experts say there’s little scientific proof that finasteride actually causes post-finasteride syndrome. This means that very few men continue to experience side effects after stopping treatment.

With that said, you should make the decision that’s right for you. And to do that, we always recommend contacting your doctor if you have questions about the side effects. You may also report side effects to the FDA at 1-800-FDA-1088.

Photo by Jarrod Reed on Unsplash

The information provided in this article is not a substitute for professional medical advice, diagnosis, or treatment. You should not rely upon the content provided in this article for specific medical advice. If you have any questions or concerns, please talk to your doctor.

Finasteride is an oral medication used to treat male pattern baldness in men only. It is not for use by women. When used by men, finasteride is generally safe but it can also cause serious side effects, including but not limited to allergic reactions, sexual dysfunction, depression, and high-grade prostate cancer. Most patients find that problems with sexual function resolve when they stop taking the medicine. For full prescribing information, view the drug label information.