Medicines
Finasteride and PSA: Why the Number Reads Lower
Finasteride and PSA are linked because finasteride lowers PSA, according to the National Cancer Institute. The drug changes how the test is read. Tell your doctor you take it before any PSA test, so the result is read in that light.
Written by the Protoflow label deskUpdated · 4 min read
The link01
Does finasteride lower PSA?
Yes. Finasteride and dutasteride both lower PSA (NCI, PSA Test Fact Sheet).
Finasteride is a 5-alpha reductase inhibitor, a class doctors use to shrink or slow prostate growth (NIDDK, BPH Treatment). The AUA offers it to men with prostate enlargement, meaning volume above 30 g or PSA above 1.5 ng/mL (AUA BPH Guideline (Sandhu 2023 amendment)). The PSA drop comes with how the medicine acts on the gland.
Your doctor knows to adjust. Your job is to tell them every medicine, including those from a pharmacy shelf.
Reading the result02
How should a PSA test be read on finasteride?
With care. The number is lower than it would be off the medicine, so a doctor interprets it differently.
| Factor | Effect on PSA |
|---|---|
| Finasteride, dutasteride | Lowers it (NCI, PSA Test Fact Sheet) |
| BPH, prostatitis, infection | Can raise it (NCI, PSA Test Fact Sheet) |
| Saw palmetto | Does not appear to affect readings (NCCIH, Saw Palmetto) |
For how the test works, see PSA test explained.
The medicine03
What else should you know about finasteride?
MedlinePlus lists slow action and sexual side effects.
- It may take at least 6 months to improve BPH symptoms (MedlinePlus, Tamsulosin)
- Erection trouble, lower desire and ejaculation problems can occur, and may continue after stopping (MedlinePlus, Tamsulosin)
- It may increase the risk of high-grade prostate cancer (MedlinePlus, Tamsulosin)
Those are reasons to talk with your prescriber, not to stop on your own.
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See packsSupplements04
Does a prostate supplement change this?
We found no source that it does. Still, list it for your doctor.
The NCI page does not mention herbs, and the label desk cannot say how any capsule affects a PSA reading (NCI, PSA Test Fact Sheet). Protoflow's saw palmetto is 84.5 mg a day (NCCIH, Saw Palmetto). Keep taking finasteride as prescribed, and read Protoflow and medicines.
FAQ05
Protoflow questions people ask
How long after starting finasteride does PSA drop?
Our sources do not give a timeline. Ask your urologist when to take a baseline and how to read later results (NCI, PSA Test Fact Sheet).
Should I stop finasteride before a PSA test?
Do not stop on your own. Tell the doctor you take it so the result is read correctly (NCI, PSA Test Fact Sheet), and let them decide.
Why does finasteride raise a high-grade cancer warning?
MedlinePlus says it may increase the risk of high-grade prostate cancer (MedlinePlus, Tamsulosin). Talk to your prescriber about that tradeoff and about screening.
Is finasteride the same as dutasteride?
They are related 5-alpha reductase inhibitors, and both lower PSA (NCI, PSA Test Fact Sheet). Which one fits is a prescriber's call.
Can PSA still find cancer on finasteride?
Yes, but doctors read it differently, since the drug lowers the number (NCI, PSA Test Fact Sheet). Another reason to name the medicine at every visit.
Who wrote this06
Written and reviewed by
Pages built from the label, the brand pages and linked NIH, FDA, FTC, NICE and peer-reviewed sources.
Last updated . See our editorial standards and how we check reviews. This website is run by a USA authorized Protoflow retailer, not by the manufacturer or distributor, PhytoThrive Labs. We make money when you buy through our order links.
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