Quick facts

Brand name: Propecia

Active ingredient: Finasteride

Primary condition: Male pattern hair loss (androgenetic alopecia)

Also related to: Benign prostatic hyperplasia (BPH) and, less commonly, certain prostate cancer management contexts under medical supervision

Available strengths: 1 mg (commonly used for hair loss), 5 mg (marketed as Proscar for BPH)

Propecia demonstrated efficacy for both vertex (crown) thinning and recession near the hairline in clinical trials. For more on practical use, jump to Dosage or explore Alternatives.

Intended use

Propecia (finasteride 1 mg) is prescribed for adult men to help slow hair loss and encourage regrowth where follicles are still active. It is not indicated for women or children.

Finasteride works by selectively inhibiting the conversion of testosterone to dihydrotestosterone (DHT), a hormone that shrinks susceptible hair follicles. Because results depend on continued use, stopping therapy may lead to gradual loss of any gained hair over several months.

Dosage and directions

Always use as directed by your prescriber. Typical regimen for hair loss is one 1 mg tablet by mouth once daily, with or without food, swallowed whole with water. Do not crush, split, or chew tablets.

Consistent daily use for at least 3 to 6 months is usually needed to evaluate effect. If you have questions about dose adjustments or switching to an alternative formulation, speak with your clinician. For BPH, the 5 mg strength is used under separate guidance and branding (Proscar).

Related topics: What if I forget a dose?, How to store.

Precautions

  • Allergy alert: Do not use if you have known hypersensitivity to finasteride or to chemically related agents such as dutasteride.
  • Pregnancy handling warning: Finasteride can be absorbed through the skin and may cause birth defects in a male fetus. Pregnant individuals or those who may become pregnant must not handle crushed or broken tablets.
  • PSA testing note: Finasteride reduces prostate specific antigen (PSA) levels by about 50 percent after several months. Let your clinician know you take finasteride so PSA results can be interpreted appropriately.
  • Mood and sexual health monitoring: There have been reports of decreased libido, erectile dysfunction, changes in ejaculation, depression, and rare suicidal thoughts. Seek medical advice promptly if mood changes or persistent sexual side effects occur.
  • Fertility considerations: Rare cases of reduced semen volume and altered fertility parameters have been reported; typically reversible after discontinuation.
  • Driving and alertness: Dizziness or drowsiness can occur. If affected, avoid driving or operating machinery until symptoms resolve.

For information about the USA legal framework, see Legal status.

Contraindications

  • Use in women or children
  • Known hypersensitivity to finasteride or any tablet component

Possible side effects

Commonly reported effects may include:

  • Dizziness or lightheadedness
  • Fatigue or unusual weakness
  • Sleep disturbances
  • Runny nose
  • Blurred vision
  • Changes in sexual function such as decreased libido, erectile dysfunction, or altered ejaculation

Seek urgent care for serious reactions such as:

  • Priapism (a painful or prolonged erection lasting 4 hours or more)
  • Severe dizziness or fainting
  • Signs of a serious allergic response (rash, itching, swelling, severe dizziness, trouble breathing)

Other notes: Finasteride labeling includes information about a signal for high-grade prostate cancer in some trials; discuss risks and benefits with your clinician, especially if you are undergoing prostate screening.

If you notice effects not listed here, contact your healthcare provider or pharmacist. You can also review precautions for additional context.

Drug interactions

Finasteride has no widely recognized major drug interactions. Nevertheless, provide your prescriber and pharmacist with a complete list of everything you take, including prescriptions, over-the-counter medicines, supplements, and herbs.

  • Finasteride is metabolized by hepatic pathways; clinically important CYP-mediated interactions are uncommon but possible.
  • Always consult before starting or stopping other hair loss treatments (for example, minoxidil, oral or topical) to coordinate a safe plan.

Missed dose

If you miss a dose, take it when remembered unless it is close to your next scheduled dose. If it is nearly time for the next dose, skip the missed tablet and resume the regular schedule. Do not double up.

Overdose

No specific antidote exists. If too much is taken, seek medical attention or call your local poison control center. Supportive care is typically provided. Symptoms may include nausea, chest discomfort, fainting, or heart rhythm concerns.

Storage

  • Keep at room temperature, ideally 68 to 77 F (20 to 25 C).
  • Protect from moisture and light.
  • Do not store in bathrooms.
  • Keep out of reach of children and pets.

Return to top.

Alternatives and similar medications

Several therapies can be used alone or in combination with Propecia. Discuss suitability, risks, and expected outcomes with a licensed clinician.

  • Dutasteride (brand Avodart; generic available) - Another 5-alpha-reductase inhibitor. Often used off-label for male pattern hair loss; stronger DHT suppression than finasteride. Not FDA-approved for alopecia.
  • Topical minoxidil 2 to 5 percent foam or solution - Over-the-counter option that can complement finasteride. Helps prolong the growth phase of hair follicles.
  • Finasteride 5 mg (Proscar) split by a pharmacist into 1 mg doses - Only if instructed and safely prepared; do not handle broken tablets if pregnancy is possible in the household.
  • Oral low-dose minoxidil (off-label) - Requires prescription and monitoring due to systemic effects.
  • Compounded topical finasteride or finasteride-minoxidil combinations - Off-label; may reduce systemic exposure but data are evolving.
  • Non-drug options - Microneedling, low-level laser therapy devices, hair transplantation, and cosmetic camouflaging fibers.
  • Supportive supplements - For example, saw palmetto is marketed for hair; evidence is limited and variable. Interactions and side effects are possible.

For cost comparisons, see Prices in USD. For legal aspects, review USA regulations.

Approximate prices in the USA (USD)

Prices vary widely by pharmacy, insurance coverage, discount programs, and whether you choose brand or generic. The estimates below reflect out-of-pocket monthly costs as of recent publicly available data:

  • Finasteride 1 mg generic (30 tablets): about $5 to $30
  • Propecia brand 1 mg (30 tablets): about $80 to $200
  • Finasteride 5 mg generic for BPH (30 tablets): about $5 to $20
  • Dutasteride 0.5 mg generic (30 capsules): about $10 to $60
  • Topical minoxidil OTC (1 month supply): about $10 to $30
  • Compounded topical finasteride or finasteride-minoxidil (1 month): about $30 to $80

Using prescription discount cards, mail-order pharmacies, or telehealth platforms may reduce costs. Always verify the pharmacy is legitimate; see Legal status.

Medical information notice

The information on this page is general and does not include all directions, precautions, or drug interactions. It must not be used for diagnosis or to replace care from a qualified clinician. Always follow the specific instructions provided by your prescriber and pharmacist. We do not accept liability for errors, omissions, or outcomes resulting from use of this content, including any form of self-treatment.