Podcast episode 118 (in German)
Finasteride – one hundred and seven hairs and a Dear Doctor letter
October 26, 2026
107 more hairs than in the comparison group after 1 year, counted on 5.1 square centimeters. And a Dear Doctor letter (Rote-Hand-Brief) dated September 15, 2025, on suicidal thoughts. This episode shows why both statements are true of the same tablet.
What it is about
Finasteride inhibits 5-alpha reductase, which converts testosterone to dihydrotestosterone, and thereby slows the shrinking of hair follicles in people with a predisposition. The effect was counted in 2 blinded trials, not estimated. Since a Europe-wide review procedure, suicidal thoughts have been listed as a side effect of the tablets in the product information, with unknown frequency; the reports came predominantly from men taking the drug for hair loss. The episode also puts into context sexual dysfunction, which can contribute to mood changes, and the so-called post-finasteride syndrome, which is not established as a clinical entity. The approval remains; what changed was the information. The conclusion: do not stop secretly, and in case of low mood or sexual dysfunction do not wait, but seek medical advice.
Key points
- In 2 one-year trials from 1998 with 1,553 men aged 18 to 41, blinded against placebo, the hair count after 1 year was 107 above the comparison group, after 2 years 138.
- Hairs were counted in a circle of 1 inch at the crown, from a baseline of 876 hairs; the gap also arises because the comparison group continued to lose hair.
- Over 5 years, further visible hair loss was 93 percent less likely — calculated in relative terms and measured as continued loss, not as regrowth.
- Of 325 cases of suicidal thoughts in the European adverse event database, 313 concerned finasteride; prostate use, at a 5-fold dose, produced around 10 times fewer reports.
- According to a review of 41 papers, sexual dysfunction occurred in 1.9 to 6.7 percent in placebo-controlled trials, and in 0.9 to 3.9 percent on placebo.
- A prostate trial with an average of 20 years of follow-up via insurance data found no statistically notable difference in 22 queried symptom complexes.
- The EU Commission decided in August, the German federal drug agency implemented it on September 9, and 6 days later the Dear Doctor letter went out.
Where the data stop
The frequency of suicidal thoughts is explicitly not known, a category of its own: cannot be estimated from the available data. 313 reports stand against around 270 million estimated patient-years, but a report count is not a frequency — only a fraction is reported, and the better known a side effect is, the more. Nothing was changed for the scalp spray, because the evidence was insufficient.
The reassuring long-term analysis concerns men over 50 on the higher dose. For young men taking the low dose for hair loss there is no long-term study; the existing one is reassuring, but not applicable. That the dysfunctions “mostly” resolved after stopping leaves open what happens in the others, and that is exactly what the dispute over post-finasteride syndrome hinges on. An analysis of around 143,000 posts from social networks mainly shows concern, but it is counted self-reporting and not representative. The drug is prescription-only; anyone who notices something in themselves should talk to the practice that prescribed it.
Listen (in German)
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Published on October 26, 2026.
The topic in the database
- The effect on hair has been counted, not claimed: 107 more hairs than on placebo after one year. Since September 2025 there has been a Dear Doctor letter on …Finasteride
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Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-09-22.