Finasteride: Uses, Side Effects, and Safety
Finasteride is a prescription tablet used to treat male pattern hair loss and, in higher doses, symptoms of benign enlarged prostate. It works by reducing the effects of a hormone that can contribute to hair thinning and prostate growth.
Finasteride can help slow hair loss and improve symptoms of an enlarged prostate, but it may cause sexual, breast-related, and dizziness side effects. Take it only as prescribed and discuss personal risks and benefits with your doctor or pharmacist.
Key facts at a glance
- ATC
- G04CB01
- Generic
- Finasteride
- Class
- 5-alpha-reductase-inhibitor
- Brands
- Proscar, Propecia
- Availability
- rx
- Pregnancy
- X
- Lactation
- unsafe
- Half-life (h)
- 8
- Duration (h)
- 24
- Routes
- oral
- Forms
- tablet
- Regions
- CN, US, EU, JP
- Monitoring
- psa-level
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 1mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 5mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 5mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
8 groupspregnancy
first trimesteravoid completely
contraindicated during pregnancy; women who are pregnant or may become pregnant should not handle crushed or broken tablets due to risk of absorption
not applicable - avoid use
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
second trimesteravoid completely
discontinue therapy if pregnancy occurs; avoid handling by pregnant women
not applicable - avoid use
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
nursing mothersavoid during breastfeeding
not recommended during lactation; consider alternative therapies; finasteride may be present in breast milk
monitor infant if exposure occurs
Use of this medication in this population requires careful consideration of risks and benefits.
pediatric_age
children under 18not recommended
not approved for use in pediatric patients; safety and efficacy not established in children
not applicable
Use of this medication in this population requires careful consideration of risks and benefits.
geriatric
elderly 65 plusno specific dose adjustment required for age alone
use with caution; monitor for adverse effects including decreased libido and orthostatic hypotension
regular assessment of efficacy and adverse effects
Use with caution and monitor for adverse effects.
renal_impairment
severe renal impairmentno dose adjustment required for mild to moderate impairment; use caution in severe impairment
no dose adjustment needed as finasteride is metabolized hepatically not renally; however monitor closely in severe impairment
monitor renal function periodically
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateuse with caution; no specific dose adjustment established
use with caution in patients with hepatic impairment due to metabolism in liver; monitor liver function tests
periodic liver function monitoring recommended
Use with caution and monitor for adverse effects.
hepatic_impairment
severeavoid if possible
use with extreme caution or avoid; finasteride is extensively metabolized in liver
close monitoring of liver function and drug levels if used
Use of this medication in this population requires careful consideration of risks and benefits.
Statistics and clinical data
FDA approval year
Original FDA approval for Proscar (BPH)
Drug class
Enzyme inhibitor classification
Common uses
Therapeutic indications for Proscar and Propecia
Mechanism of action
Blocks conversion of testosterone to DHT
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 22, 2026. · Read our editorial policy