Hairloss Study Abstract: The effect of finasteride, a 5 alpha-reductase inhibitor, on scalp skin testosterone and dihydrotestosterone concentrations in patients with male pattern baldness.
Title
The effect of finasteride, a 5 alpha-reductase inhibitor, on scalp skin testosterone and
dihydrotestosterone concentrations in patients with male pattern baldness.
Merck Research Laboratories, Rahway, New Jersey 07065.
Source
J Clin Endocrinol Metab, 79: 3, 1994 Sep, 703-6
Abstract
The effects of the 5 alpha-reductase inhibitor, finasteride, on scalp skin testosterone
(T) and dihydrotestosterone (DHT) levels were studied in patients with male pattern
baldness. In a double blind study, male patients undergoing hair transplantation were
treated with oral finasteride (5 mg/day) or placebo for 28 days. Scalp skin biopsies were
obtained before and after treatment for measurement of T and DHT by high pressure liquid
chromatography-RIA. In 10 male subjects studied at baseline, mean (+/- SEM) DHT levels
were significantly higher in bald (7.37 +/- 1.24 pmol/g) compared to hair-containing (4.20
+/- 0.65 pmol/g) scalp, whereas there was no difference in mean T levels at baseline. In
bald scalp from 8 patients treated with finasteride, the mean DHT concentration decreased
from 6.40 +/- 1.07 pmol/g at baseline to 3.62 +/- 0.38 pmol/g on day 28. Scalp T levels
increased in 6 of 8 subjects treated with finasteride. Finasteride decreased the mean
serum DHT concentration from 1.36 +/- 0.18 nmol/L (n = 8) at baseline to 0.46 +/- 0.10
nmol/L on day 28 and had no effect on serum T. There were no significant changes in scalp
or serum T or DHT in placebo-treated patients. In this study, male subjects treated with 5
mg/day finasteride for 4 weeks had significantly decreased concentrations of DHT in bald
scalp, resulting in a mean level similar to the baseline levels found in hair-containing
scalp.