What Is Finasteride? Uses, Dosage, and What You Need to Know in 2026

Finasteride is one of the most widely prescribed medications for men in the United States, treating two very different conditions: male pattern hair loss and enlarged prostate. Despite its widespread use, many patients start taking it without a clear picture of how it works, what to expect, or the important things they need to monitor. This guide covers the essentials.

What Is Finasteride?

Finasteride is a prescription oral medication belonging to a class called 5-alpha-reductase inhibitors (5-ARIs). It works by blocking an enzyme that converts testosterone into dihydrotestosterone (DHT), a more potent androgen responsible for prostate growth and androgenic hair loss.

It comes in two brand-name versions:

Propecia (1 mg): FDA-approved for male pattern hair loss (androgenetic alopecia) in men. First approved in 1997.

Proscar (5 mg): FDA-approved for benign prostatic hyperplasia (BPH) in men with enlarged prostate. First approved in 1992.

Both brands have generic equivalents. Generic finasteride is widely available and significantly cheaper.

What Is Finasteride Used For?

FDA-Approved Uses:

Male pattern hair loss (androgenetic alopecia): At the 1 mg dose, finasteride slows hair loss progression, and many men experience partial hair regrowth. It's FDA-approved only for men — not women (except off-label in post-menopausal women in some cases).

Benign prostatic hyperplasia (BPH): At the 5 mg dose, finasteride reduces prostate size, improving urinary symptoms and reducing the risk of acute urinary retention and the need for prostate surgery.

Off-Label Uses:

Hirsutism (excessive hair growth in women) — used off-label with contraception

Transgender women (in combination with estrogen, as an anti-androgen)

Dosage: How Much Do You Take?

For hair loss: 1 mg once daily. Must be taken consistently — benefits stop and reverse within 12 months of discontinuation.

For BPH: 5 mg once daily. May be used alone or in combination with an alpha-blocker (like doxazosin). Takes at least 6 months to achieve maximum benefit on prostate size.

Finasteride can be taken with or without food. Take it at the same time each day for consistency.

How Long Does It Take to Work?

For hair loss: 3+ months required before any visible benefit. Maximum effect may take up to 12 months. Studies show finasteride reduces scalp DHT levels within 24 hours of the first dose, but visible hair changes take much longer.

For BPH: At least 6 months before full symptom relief and prostate size reduction are typically observed.

Who Should NOT Take Finasteride?

Pregnant women or women who may become pregnant: Finasteride causes abnormal development of male fetal genitalia. Pregnant women should not even touch crushed or broken tablets, as the drug can be absorbed through the skin.

Children: Not indicated for pediatric patients.

Anyone with liver disease: Use with caution. Finasteride is extensively metabolized in the liver, and clearance may be reduced.

Men planning to father children: Discuss with your doctor — finasteride may reduce semen quality, though this is generally reversible.

Is Finasteride a Controlled Substance?

No. Finasteride is not a controlled substance. It does not have DEA scheduling and can be prescribed by any licensed healthcare provider, transferred between pharmacies freely, and filled via mail-order or telehealth with no special restrictions.

How Much Does Finasteride Cost?

Generic finasteride is inexpensive. With a GoodRx coupon, a 30-day supply of 1 mg generic finasteride can cost as little as $9.25. The 5 mg generic is similarly priced. Brand-name Propecia retails for $100–$150/month, and brand Proscar retails for around $214/month — but there's no clinical reason to pay for brand when generic is available.

Want to understand how finasteride works at a deeper level? See: How Does Finasteride Work? Mechanism of Action Explained in Plain English.

For savings tips and coupon details, see: How to Save Money on Finasteride in 2026.