Proscar

Medically reviewed by Patricia Weiser, PharmD on May 4, 2023
Written by Alex Brewer, PharmD, MBA

These approved uses differ based on the dose of finasteride your doctor prescribes.

This article describes finasteride’s uses, side effects, and more. Below you’ll find some coupon options for finasteride.

Finasteride may cause mild or serious side effects. More common mild side effects of finasteride and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

To learn more about finasteride’s side effects, see this article or ask your doctor or pharmacist. You can also read the prescribing information* for finasteride.

* To view finasteride’s prescribing information, see the “Article resources” section below.

Mild side effects

More common mild side effects reported with finasteride are listed below. These side effects may differ based on the dose of finasteride you take.

This article doesn’t include all possible mild side effects of the drug. To learn more about finasteride’s side effects, see the drug’s prescribing information.*

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Finasteride oral tablet’s mild side effects include:

• breast growth in males†
• decreased sex drive
• erectile dysfunction (difficulty getting or maintaining an erection)
• decreased amount of semen with ejaculation
• mild allergic reaction‡

* To view finasteride’s prescribing information, see the “Article resources” section below.
† Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.
‡ For details about this side effect, see the “Interactions and warnings for finasteride” section below.

Serious side effects

Serious side effects of finasteride are listed below. These side effects may differ based on the dose of finasteride your doctor prescribes.

This article doesn’t include all possible serious side effects of the drug. To learn more about finasteride’s side effects, see the drug’s prescribing information.*

With many drugs, serious side effects are possible but not common. If you have serious side effects from finasteride, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, finasteride’s serious side effects include:

• possible increased risk of prostate cancer
• low blood pressure when standing or sitting up, which could result in fainting and falls
• severe allergic reaction†

* To view finasteride’s prescribing information, see the “Article resources” section below.
† For details about this side effect, see the “Interactions and warnings for finasteride” section below.

Below you’ll find answers to a few commonly asked questions about finasteride.

Is finasteride similar to dutasteride or saw palmetto?

Finasteride is similar to dutasteride but not saw palmetto (a supplement made from a kind of palm). Both finasteride and dutasteride belong to a group of prescription drugs called 5-alpha reductase inhibitors. Saw palmetto isn’t a prescription drug.

Both finasteride and dutasteride are used to treat an enlarged prostate. Finasteride (Propecia) is also used to treat male* pattern hair loss. Dutasteride isn’t approved for this purpose, but doctors may prescribe it off-label.†

Saw palmetto is an over-the-counter dietary supplement. Some people take it for prostate health and other conditions. But large studies suggest that saw palmetto isn’t more effective than a placebo for treating symptoms of an enlarged prostate. (A placebo is a pill that contains no active drug.)

Talk with your doctor or pharmacist to learn more about how finasteride compares with other drugs or supplements. You can also read this article about how dutasteride compares with finasteride for treating an enlarged prostate.

* Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.
† With off-label use, a drug is prescribed for a purpose other than its approved uses.

Is it safe for females to take finasteride? Do females experience different side effects from the drug compared with males?

No, it’s not safe for females* to take finasteride. The drug isn’t approved for use in females. The drug is used only in males.*

Females should not take finasteride for any reason due to the risk of possible side effects.

If you’re female and interested in the drug’s approved uses,† talk with your doctor. They may be able to recommend other treatment options that are safe for you to take.

* Sex and gender exist on spectrums. In this article, we use the terms “male” and “female” to refer to a person’s sex assigned at birth.
† To learn about finasteride’s uses, see the “Uses of finasteride” section below.

How long do side effects of finasteride last? Are there ways to reduce side effects?

It depends. Some side effects* of finasteride are temporary and may go away within a few days. Others may last for a few weeks or even months. But continued treatment with the drug may reduce the severity or frequency of some side effects. In the drug’s studies, mild side effects (including sexual side effects) often went away after continuing the treatment long term.

Talk with your doctor or pharmacist if you experience side effects from finasteride that bother you or don’t go away. They can review your symptoms and suggest other possible treatment options. This may include encouraging you to continue taking finasteride to find out whether side effects ease over time.

* To learn more about finasteride’s side effects, see the “Side effects of finasteride” section above.

What is finasteride’s half-life? How does the drug work?

Finasteride’s half-life is around 5 to 6 hours. A drug’s half-life describes how long it takes your body to get rid of half of a dose after taking it.

Finasteride works by blocking the process that changes the testosterone hormone into dihydrotestosterone (DHT). In the prostate, DHT signals prostate cells to grow. Finasteride treatment decreases the amount of DHT in your body, reducing the size of the prostate over time. This helps treat symptoms of an enlarged prostate.

It’s not fully understood how decreasing the DHT level in the body treats male* pattern hair loss. But in adults with male pattern hair loss, there’s more DHT in hairless areas than in hair-covered areas of the scalp.

It can take several months before finasteride works to ease your symptoms. Talk with your doctor or pharmacist if you have questions or concerns about whether the medication is working for your condition.

* Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.

Does finasteride cause long-term side effects?

Yes, in some cases, finasteride may cause long-term side effects. Examples include the following:

• Sexual side effects, including erectile dysfunction. These side effects may last a while, but they often go away with continued treatment (more than 1 year).
• A possible increased risk of prostate cancer.
• Low blood pressure when standing or sitting up. You may have an increased risk of this side effect throughout finasteride treatment. But the risk usually decreases once you stop taking the drug.

Long-term side effects can occur if you take the drug for a long time. Or they may last for a while after you’ve stopped taking the drug.

Talk with your doctor to learn more about these side effects. You can ask your doctor how to best manage them if they occur and how long they may last.

To learn more about finasteride’s side effects, see the “Side effects of finasteride” section above.

The Food and Drug Administration (FDA) approves prescription drugs such as finasteride for certain conditions. Approved uses for finasteride are described below.

Note: Finasteride is approved for use only in adult males. The drug isn’t approved for any use in females or children. (Sex and gender exist on spectrums. In this article, we use the terms “male” and “female” to refer to a person’s sex assigned at birth.)

Use for hair loss

Doctors may prescribe finasteride oral tablet for treating male pattern hair loss. It’s used for this purpose in adult males. It’s usually prescribed as a long-term treatment.

Male pattern hair loss refers to ongoing hair loss from the scalp sometime after puberty. This pattern of hair loss commonly begins at the crown of your head or your temples. You may develop a single bald spot on your head. Or you may have a hairline that begins receding and forms an “M” shape. This receding line may continue until most of, or all, your hair stops growing.

Use for benign prostatic hyperplasia

Doctors may prescribe finasteride oral tablet for treating an enlarged prostate that causes symptoms. This condition is also known as benign prostatic hyperplasia (BPH). Finasteride is used for this purpose in adult males and is usually prescribed as a long-term treatment.

The prostate is a small gland that’s part of the male reproductive system. With BPH, your prostate cells multiply (make more cells) excessively. These additional cells cause the prostate to swell, which squeezes the urethra. In males, the urethra carries urine from the bladder to the tip of the penis. So an enlarged prostate limits urine flow through the urethra.

Symptoms of BPH include:

• waking up at night to urinate two or more times
• a weak urinary stream
• slowed or delayed urination
• a sudden urge to urinate
• dribbling at the end of your urine stream

Finasteride may be prescribed together with the drug doxazosin to help slow the progression (worsening) of BPH.

Doctors may not prescribe finasteride oral tablet in certain situations, such as to help prevent prostate cancer. Finasteride isn’t approved for this use.

The dosage of finasteride your doctor prescribes may vary based on your condition and certain other factors. Talk with your doctor about the dosage you should take.

Taking finasteride

Finasteride oral tablet is swallowed with or without food.

Your doctor will talk with you about how to take finasteride. They’ll explain how much to take and how often. Always follow your doctor’s recommendation.

Overdose of finasteride

You should not take more finasteride than your doctor prescribes. For some drugs, doing so may lead to serious side effects or overdose. For details about finasteride side effects, see the “Side effects of finasteride” section above.

If you think you’ve taken too much finasteride, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to your closest emergency room.

You may be able to save money on your prescription for finasteride by using our Perks discount coupons. They can be found at the end of this article.

If you have questions about how to pay for finasteride, talk with your doctor or pharmacist. You can also learn more about the cost of finasteride in this article.

Note: Optum Perks coupons cannot be used with insurance copays or benefits.

For some medications, certain things may affect how the drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.

Before you take finasteride, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:

• prescription medications
• over-the-counter medications
• vitamins, herbs, or supplements

To learn about drug-condition interactions, see the “Warnings for finasteride” section just below.

Warnings for finasteride

Some people should not take finasteride and others should take it cautiously.

Finasteride could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether finasteride is a safe option for you. These warnings may differ based on the form of finasteride you take.

Ask your doctor about specific warnings for finasteride, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

Allergic reaction

Finasteride can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to finasteride or any of its ingredients, your doctor will likely not prescribe finasteride. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to finasteride, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Pregnancy or breastfeeding and finasteride

Information about finasteride and pregnancy and breastfeeding is described below.

Note: Finasteride is approved for use* only in males. The drug isn’t approved for any use in females. (Sex and gender exist on spectrums. In this article, we use the terms “male” and “female” to refer to a person’s sex assigned at birth.)

* To learn about finasteride’s uses, see the “Uses of finasteride” section above.

Finasteride and pregnancy

Finasteride should not be taken during pregnancy. This drug is not approved for use in females. If you or your partner can become pregnant, talk with your doctor before taking this medication. They may suggest birth control options to use during treatment with finasteride.

Finasteride and breastfeeding

It’s not known whether finasteride should be taken while breastfeeding. Finasteride isn’t approved for use in females, so researchers haven’t studied the drug in this situation.

This article describes finasteride’s uses and dosage, ways to save on cost, and more. Let your doctor know if you have questions about finasteride or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• If I have both an enlarged prostate and hair loss, can you prescribe finasteride to treat both conditions?
• Does my health history increase my risk of side effects from taking finasteride?
• I’ve had prostate cancer. Is it safe for me to take finasteride?
• If I have side effects from taking the 5-milligram (mg) dose of finasteride, can you prescribe a lower dose for me to try?

• Finasteride – finasteride tablet, coated. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/49eb3a1e-d7e6-4652-aa6d-6abf21af34a6/spl-doc
• Finasteride – finasteride tablet, film coated. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/e482a50d-db15-4407-85c9-160c88e8a657/spl-doc
• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm
• Spotlight on saw palmetto: What the science says. (2019). https://www.nccih.nih.gov/health/providers/digest/spotlight-on-saw-palmetto-science

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.