Quote from: KayXo on January 08, 2018, 08:45:28 AM
It only converts testosterone to DHT, has no bearing on the other androgens.
No. Dutasteride inhibits only 5-alpha reductase enzyme but in contrast to finasteride that predominantly inhibits Types 2 and 3 enzyme, dutasteride inhibits all types, 1,2, 3.
Androstendione can convert to DHT.
https://www.ncbi.nlm.nih.gov/pubmed/2242346Androstenedione is an important precursor of dihydrotestosterone in the genital skin of women and is metabolized via 5 alpha-androstanedione.
Abstract
Androgen action is largely determined by the formation of dihydrotestosterone in target tissues. In women, androstenedione is the major precursor of dihydrotestosterone production in female genital skin. The present study was initiated to determine whether androstenedione is converted to dihydrotestosterone primarily via testosterone or 5 alpha-androstane-3,17-dione (5 alpha-androstanedione), and to examine the pathway of androstenedione metabolism in genital skin. Genital skin was obtained from 9 normal premenopausal women and 2 normal men. Each tissue was incubated with [3H]androstenedione in RPMI-1640 medium for 1 h at 37 degrees C in 95% O2/5% CO2. The metabolites were separated and purified by paper partition and thin-layer chromatography. The conversions of androstenedione to 5 alpha-androstanedione and to androsterone were similar (10.45 +/- 1.46 and 11.04 +/- 2.04%/200 mg tissue), and were approx. 12, 8 and 23 times higher than the conversion of androstenedione to testosterone, dihydrotestosterone and 5 alpha-androstane-3 alpha,17 beta-diol, respectively. The male samples showed a similar pattern of metabolism. These data indicate that 5 alpha-androstanedione is the most important intermediate in the conversion of androstenedione to dihydrotestosterone. The data also confirm the importance of 5 alpha-reductase activity over that of 17 beta-hydroxysteroid oxidoreductase activity in the expression of androgen action in women.
What I like about Dutasteride is it is has roughly double the half life of Finesteride, around 3 weeks for finesteride versus 6 1/2 weeks for dutasteride once it has built up to it's serum concentration. It stays in the system very long and only needs a very low dose to build up. In 30 days it reduces DHT to zero. With finesteride used at the maximum dose one third of DHT will remain and DHT is a very potent estrogen blocker. DHT also converts to androstenediol which is a stronger androgen than DHT.