Finasteride Interactions: Drug & Supplement Guide
Medically reviewed by [Reviewer Name, MD] | Last reviewed: August 2026 | Editorial policy
Finasteride has a generally safe drug interaction profile, but there are important considerations with specific medications, supplements, and substances. This hub covers the most clinically relevant interactions.
Interactions by Category
- Finasteride and alcohol — No significant pharmacokinetic interaction; sexual function overlap issue
- Finasteride and biotin — No drug interaction, but high-dose biotin falsifies PSA and thyroid lab tests
- Prescription drug interactions — CYP3A4 inhibitors/inducers, alpha-blockers, warfarin, and other key interactions
Always Tell Your Prescriber
Before starting finasteride, provide your prescribing clinician with a complete list of:
- All prescription medications
- Over-the-counter medications (including NSAIDs, antihistamines)
- Supplements and vitamins (including biotin, saw palmetto, zinc)
- Herbal preparations (St. John’s Wort is a CYP3A4 inducer)
- Recreational substance use (alcohol frequency, cannabis)
See also: Dosage guide | Side effects | Getting a prescription