Finasteride Before and After: Clinical Trial Data
Medically reviewed by [Reviewer Name, MD] | Last reviewed: August 2026 | Editorial policy
This page presents clinical trial before-and-after data for finasteride, objective, measured outcomes from randomized controlled trials, not individual case photos. User-shared photos vary enormously based on lighting, angle, and selection bias and are not a reliable guide to expected results.
Hair Count: Before vs. After in Key Trials
| Trial | Duration | Change (Fin 1 mg) | Change (Placebo) | Net Difference |
|---|---|---|---|---|
| Kaufman 1998 (vertex) | 12 months | Increase from baseline | Hair loss from baseline | +107 hairs in a 1-inch circle (5.1 cm²) |
| Rossi 2011 (10-year) | 10 years | Efficacy not reduced over time; 42.8% of men aged 20 to 30 did not improve | N/A (no placebo at 10yr) | N/A |
Investigator-Rated Global Photographic Assessment
In the key trials, trained investigators assessed standardized scalp photographs at baseline and 12 months, blinded to treatment:
| Rating at 12 months | Finasteride 1 mg | Placebo |
|---|---|---|
| Greatly increased | 14% | 1% |
| Moderately increased | 34% | 6% |
| Slightly increased | 23% | 14% |
| No change | 12% | 7% |
| Slightly decreased | 11% | 22% |
| Moderately decreased | 5% | 31% |
| Greatly decreased | 1% | 19% |
The key finding: 86% of finasteride users showed no further hair loss at 12 months vs. 42% on placebo. 48% showed visible improvement vs. 7% on placebo.
What Clinical “Before and After” Actually Looks Like
Clinical photographs used in trials are standardized: consistent lighting (typically cross-polarized), identical camera distance, same scalp position marked by reference points. Under these conditions, a +7 hairs/cm² change in a 1-inch circle corresponds to roughly 50-70 additional hairs visible in the target area, a change that is detectable by trained investigators but may or may not be noticeable to patients in daily life without standardized photography.
See also: Full results timeline | Shedding phase | What to expect at 1 year | 1998 trial data
Sources
- Kaufman KD, et al. “Finasteride in the treatment of men with androgenetic alopecia.” J Am Acad Dermatol. 1998;39(4):578-589.
- Rossi A, et al. “Finasteride, 1 mg daily administration on male androgenetic alopecia in different age groups: 10-year follow-up.” Dermatol Ther. 2011;24(4):455-461.