What finasteride is and its FDA status
Finasteride is a 5-alpha reductase inhibitor, and the 1 mg tablet sold as Propecia is FDA-approved for male pattern hair loss in men only. Finasteride was first approved in 1992 at 5 mg for an enlarged prostate, and Drugs@FDA lists the Propecia application, approved in December 1997, for hair. Generic 1 mg tablets are widely available.
MedlinePlus describes the same split: one drug, two doses, used either for benign prostatic hyperplasia or for hair loss at the crown and top of the head. It is a tablet taken once a day, with or without food.
How finasteride slows crown and vertex loss
Finasteride works by lowering DHT. In men with male pattern hair loss, balding areas of the scalp contain more DHT, a potent form of testosterone that gradually shrinks genetically sensitive follicles until they make only fine, short hairs. Finasteride blocks type II 5-alpha reductase, the enzyme that makes most of that DHT, and the Propecia label reports a 65% drop in blood DHT within 24 hours of a 1 mg dose, along with lower scalp DHT.
The label’s trials were in men aged 18 to 41 with mild to moderate loss at the vertex (crown) and the anterior mid-scalp. Results were about stopping loss more than regrowing a full head:
| Outcome in the vertex trials | Propecia | Placebo |
|---|---|---|
| Further hair loss at 12 months | 14% | 58% |
| Further hair loss at 2 years | 17% | 72% |
| Further hair loss at 5 years | 35% | 100% |
| Visible increase on photos at 12 months | 48% | 7% |
The American Academy of Dermatology summarizes it the same way: finasteride slows further loss in about 80% to 90% of men, and regrowth is more likely when it is started early. The label says daily use for three months or more is usually needed before benefit shows, and the effect reverses within 12 months of stopping. Our page on male pattern hair loss covers the condition itself.
Sexual and mood side effects on the label
Sexual side effects are the main reason men hesitate, and the label is specific. In the first-year trials, decreased libido was reported by 1.8% of men on finasteride versus 1.3% on placebo, erectile dysfunction by 1.3% versus 0.7%, and ejaculation problems by 1.2% versus 0.7%. Overall, 3.8% reported at least one of these, compared with 2.1% on placebo, and they eased in most men who stopped and in most who continued.
Since approval, the label has added reports gathered after marketing:
- sexual problems that continued after stopping the drug, including erectile, libido, ejaculation and orgasm problems;
- depression, suicidal thoughts and suicidal behavior;
- reduced fertility or semen quality, testicular pain, breast tenderness or enlargement, and rare male breast cancer.
Post-marketing reports cannot prove how often these happen or whether the drug caused each one, but they are taken seriously. Any new low mood or thoughts of self-harm means stopping and calling your provider, and a crisis needs 911 or the 988 lifeline. Our pages on whether finasteride side effects are permanent and whether finasteride lowers testosterone go deeper.
A newer issue is compounded topical finasteride. In April 2025 the FDA warned that no topical finasteride is FDA-approved and that it had received 32 adverse event reports from 2019 to 2024, mostly describing effects that persisted after stopping.
Why finasteride changes PSA readings
Finasteride lowers PSA, the prostate cancer screening marker, so a PSA result on finasteride cannot be read like an untreated one. The label reports that at the 5 mg prostate dose PSA falls by about 50% in older men, and in younger men on 1 mg the average PSA fell from 0.7 to 0.5 ng/mL over a year. Clinicians often adjust for this, and any confirmed rise from your lowest PSA on finasteride deserves evaluation even if the number still looks normal.
Tell anyone who orders your PSA that you take finasteride, and get a baseline before starting if you are in a screening age group. Our page on PSA on finasteride explains how results are interpreted.
Who should not take finasteride, and monitoring
Finasteride is not for women or children, and women who are or may become pregnant should not handle broken tablets. Men planning a pregnancy soon, men with a history of depression, and men already worried about sexual function should weigh it carefully with a provider. Monitoring is practical: photos of the crown and hairline every few months, a check on mood and sexual function at each follow-up, and PSA interpretation that accounts for the drug. Judge the result at about a year rather than at a few weeks, since the label’s photo comparisons were made at 12 months and early months can look unchanged.
Finasteride, PRP and how Ultimate Male fits in
Ultimate Male’s hair restoration service is PRP therapy, which concentrates your own platelets and injects them into thinning areas; finasteride is not on the clinic’s menu. PRP for hair is not FDA-approved for that use, and the evidence is mixed to promising. Because finasteride lowers DHT while PRP aims to support the follicle directly, many men ask about using both, and our page on PRP and finasteride together covers that question.
At a consultation, the provider looks at your pattern of loss, family history and labs, discusses where medicines such as finasteride or topical minoxidil fit alongside PRP, and is clear about which parts the clinic provides. If PRP suits you, a session plan follows; if not, you leave with an honest view of the options.
