5 AR inhibitors and semen parameters

The effect of 5alpha-reductase inhibition with dutasteride and finasteride on semen parameters and serum hormones in healthy men

J Clin Endocrinol Metab. 2007 May;92(5):1659-65

CONTEXT:
Dutasteride and finasteride are 5alpha-reductase inhibitors (5ARIs) that dramatically reduce serum levels of dihydrotestosterone (DHT).

OBJECTIVE:
Because androgens are essential for fertility, we sought to determine the impact of 5ARI administration on serum testosterone (T), DHT, and spermatogenesis.

DESIGN, SETTING, SUBJECTS, AND INTERVENTION:
We conducted a randomized, double-blinded, placebo-controlled trial in 99 healthy men randomly assigned to receive dutasteride (D; 0.5 mg) (n = 33), finasteride (F; 5 mg) (n = 34), or placebo (n = 32) once daily for 1 yr.

MAIN OUTCOME MEASURES:
Blood and semen samples were collected at baseline and 26 and 52 wk of treatment and 24 wk after treatment and were assessed for T, DHT, and semen parameters.

RESULTS:
D and F significantly (P < 0.001) suppressed serum DHT, compared with placebo (D, 94%; F, 73%) and transiently increased serum T. In both treatment groups, total sperm count, compared with baseline, was significantly decreased at 26 wk (D, -28.6%; F, -34.3%) but not at 52 wk (D, -24.9%; F, -16.2%) or the 24-wk follow-up (D, -23.3%; F, -6.2%). At 52 wk, semen volume was decreased (D, -29.7%; F, -14.5%, significantly for D) as was sperm concentration (D, -3.2%; [corrected] F, -7.4%, neither significant).

There was a significant reduction of -6 to 12% in sperm motility during treatment with both D and F and at follow-up. Neither treatment had any effect on sperm morphology. CONCLUSIONS: This study demonstrates that the decrease in DHT induced by 5ARIs is associated with mild decreases in semen parameters that appear reversible after discontinuation.

you cannot compare side by side, Finasteride and Dut, which both reduce SERUM DHT LEVELS, you cannot compare the effects of these two drugs , with Saw Palmetto for example, which has been shown NOT TO REDUCE serum DHT levels

reducing serum dht levels , in my opinion, is bad, and causes all the nasty side effects of loss of libido etc

Fin, DUT and Saw Palmetto are all three 5 ar inhibitors, but that does not make them equal and comparable

apparently the Naturals work in a different pathway or method which is less detrimental to the blood certainly, and to the body in general