Does Finasteride Interact With Testosterone?
Because of the ability of Type II 5α-reductase inhibitors to inhibit the conversion of testosterone to 5α-dihydrotestosterone (DHT), finasteride may cause abnormalities of the external genitalia of a male fetus of a pregnant woman who receives finasteride.
Severity: Contraindicated
Severity basis: contraindications section (keywords: contraindications section). Combining Finasteride (5-alpha reductase inhibitor) and Testosterone (Androgen (testosterone replacement)) is classified as a contraindicated interaction.
What to Do
This combination is contraindicated on the FDA label. Do not take these together unless your prescriber explicitly directs it.
From the FDA Label
Because of the ability of Type II 5α-reductase inhibitors to inhibit the conversion of testosterone to 5α-dihydrotestosterone (DHT), finasteride may cause abnormalities of the external genitalia of a male fetus of a pregnant woman who receives finasteride.
Source: FDA structured product labeling (set_id 00e934bb-c15b-490a-a852-839689a1231a).
Testosterone
Androgen (testosterone replacement)
Brands: Depo-Testosterone, Xyosted
View Testosterone safety profileCheck these against your full medication list in our free Interaction Checker
This information is educational — not medical advice.
This page is provided for general educational purposes and summarizes publicly available data from sources such as the U.S. Food & Drug Administration. It is not a substitute for the judgment of a licensed clinician and should not be used to start, stop, or change any medication. It may be incomplete or out of date, and individual circumstances vary. Always talk with your prescriber or pharmacist about your specific medications and health conditions. If you think you may have a medical emergency, call 911.