6 Finasteride Side Effects You Should Know About

Finasteride (Propecia, Proscar) is a medication with two main uses. Proscar treats enlarged prostates caused by benign prostatic hyperplasia (BPH). Propecia, a lower dose of finasteride, treats male pattern hair loss.

No matter what you’re taking finasteride for, it’s common to wonder about its possible side effects and how to manage them. We’ll discuss that, and when to seek medical care for side effects, below.

Finasteride side effects at a glance

Most finasteride side effects are hormone-related. That’s because it lowers levels of a hormone called dihydrotestosterone (DHT) in the body. Most side effects are more likely with the higher (5 mg) dosage used to treat BPH. The lower (1 mg) finasteride dose is most often associated with sex-related side effects.

Common side effects (happened to more than 1% of participants in clinical trials):

• Erectile dysfunction

• Reduced libido (sex drive)

• Decreased sperm count

• Ejaculation issues

Rare side effects (happened to less than 1% of participants in clinical trials):

• Male breast enlargement (gynecomastia)

• Breast tenderness

• Skin rash

• Testicular pain

• Depression

• Increased risk of prostate cancer and male breast cancer

• Birth defects if taken or handled when pregnant

• Allergic reactions

Below, we’ll go into more detail about six possible finasteride side effects and how to manage them.

1. Erectile dysfunction

Erectile dysfunction (ED) is the most commonly reported finasteride side effect. You may have trouble getting or maintaining an erection. You may also have a lower amount of ejaculate, due to finasteride’s effects on your prostate.

ED symptoms may improve over time as your body adjusts to the medication. But in the meantime, talk to your prescriber about treatment options. There are several ED medications you can take with finasteride to help manage this side effect. So don’t hesitate to let your healthcare team know if it’s a problem for you.

2. Decreased sex drive

A decrease in sex drive (low libido) is a possible finasteride side effect. In clinical studies, about 6% of people reported this side effect (about 2% for low-dose finasteride). And your sex drive may improve over time as your body adjusts to the medication.

Keep in mind that stress and lack of sleep can also lower your libido. So getting regular exercise, having good sleep habits, and eating a balanced diet may help give your sex drive a boost.

Let your healthcare team know if low sex drive is affecting your quality of life. They can suggest options for managing this side effect or switch you from finasteride to a different medication for your symptoms.

3. Enlarged breasts in males

It’s not common, but enlarged breast tissue (gynecomastia) can develop in some men taking high-dose finasteride. Sore or tender breasts are also possible. And unlike the previous side effects, the chance of breast-related side effects seems to go up the longer you take finasteride.

While this side effect can be concerning, it’s not usually dangerous to your health. It should go away once you stop taking finasteride. That being said, you should still let your medical care team know about any breast changes you experience. In rare cases, they may be a sign of male breast cancer that’s unrelated to finasteride.

Good to know: Breast-related side effects were only reported in clinical studies of the 5 mg finasteride dosage. There were no reports of these side effects with the 1 mg dosage.

4. Depression

Depression is another possible finasteride side effect. It wasn’t reported in initial clinical studies, but later reviews found a higher risk of depression and suicidal thoughts in people taking finasteride versus those who aren’t.

The sex-related side effects of finasteride may contribute to depression symptoms. And it’s possible for these symptoms to persist even after you stop taking finasteride — more on that later.

If you notice a change in your mood while taking finasteride, let your prescriber know. They can help determine the best way to manage it.

If you or someone you know is having thoughts of suicide, you’re not alone, and help is available. Call the National Suicide Prevention Lifeline at 988, or text HOME to 741-741 to reach the Crisis Text Line.

5. Low blood pressure

Finasteride may raise your risk of orthostatic hypotension. This is when your blood pressure drops after you sit up or stand after lying down. It can make you feel dizzy or even pass out in some cases.

This side effect is more likely if you take finasteride along with an alpha blocker (another type of BPH medication). Tamsulosin (Flomax) and doxazosin (Cardura) are common examples.

It’s a good idea to take your time when sitting up or standing while taking finasteride. If you feel dizzy, sit down or hold on to someone or something for support to avoid falls. If this side effect becomes bothersome, let your prescriber know. They may need to adjust your medications to manage it.

6. Post-finasteride syndrome

Most finasteride side effects will resolve on their own after you stop taking the medication. But in rare cases, they may continue to be a problem for you. Finasteride side effects that last more than 3 months after stopping the medication are referred to as post-finasteride syndrome.

Post-finasteride syndrome can include:

• Sexual side effects: Low sex drive or erectile dysfunction

• Physical side effects: Enlarged breasts or chronic fatigue

• Mental side effects: Depression or suicidal thoughts

It’s not clear how common post-finasteride syndrome is, since most cases are self-reported. And there’s no known treatment for it at this time. But your healthcare team can help you address individual symptoms. So be sure to let them know if you have lingering finasteride side effects after you’ve stopped taking it. The Post-Finasteride Syndrome Foundation can also provide resources and support.

When should you seek medical care for finasteride side effects?

It’s a good idea to let your healthcare team know about any finasteride side effects you experience. They can prescribe other medications to help, or they may suggest an alternative to finasteride. Be sure to let your care team know if your finasteride side effects persist after you stop taking it.

Breast changes and depression require more urgent attention to make sure there isn’t something more serious going on. And if you’re having suicidal thoughts, it’s best to seek medical care right away.

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Written by:

Jill Barat, PharmD

Jill Barat, PharmD has nearly 10 years of experience as a pharmacist, including serving as the pharmacist in charge at an independent sterile and non-sterile compounding pharmacy. She also worked as the head of medical content for a telemedicine company.

Edited by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

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