Chemical Name(s):
17a-methyl etioallocholan 17b-ol 3-hydroxyimine

Chemical Formula: C20H33NO2
Molecular Weight: 319.5
Q Qatio: 2.4
Anabolic #: 380/24
Androgenic #: 158/20
Oral Bioavailability: Estimated at 40%
AR Binding Affinity: NA
SHBG Binding Affinity: High
Half Life: NA
Legal Status (US): Not listed as a controlled substance

Average Dose:
75-100mg/day standalone
50-75mg/day when stacking

Average Cycle Length: 4-6 weeks

Promestanolone is a 17aa pro-steroid which converts to the illegal anabolic steroid methyl-DHT (mestanolone).

There is no human clinical data on promestanolone, but it is most likely exerting its effects by converting to methyl-DHT. The acidic environment in the stomach would be responsible for converting the 3-hydroxyimine group to a 3-one — thus rapidly changing it to methyl DHT. Therefore results and side-effects would be considered to be very similar to methyl-DHT.

Although DHT can be deactivated in skeletal muscle tissue by 3b-HSD it is likely that this enzyme pathway can be overwhelmed if this compound is taken at a high enough dose. Methyl-DHT has some activity on the progestin receptor, but not to a high degree. It has moderate anabolic but high androgenic effects. It binds strongly to SHBG, therefore free testosterone and estrogen can be expected to rise by displacement from SHBG.

Since this is a 17aa compound, liver toxicity will be an issue with high doses or long term use. For this reason users should consider priming the liver with a liver supporting supplement before and during a Promestanolone cycle. Users will also experience minimal subcutaneous water retention since there is no conversion to estrogen. However, intracellular water and sodium retention will increase by inhibition of 11-beta hydroxylase and mineralocorticoid build up.

Users may also experience an increase in aggression and mood swings which is a common side effect of many steroids with high androgenic value. This makes this compound an excellent pre-lifting or pre-competition steroid.

Promestanolone should produce solid lean gains in muscle as a standalone. However for those looking to add additional bulk to their cycle, promestanolone would stack with with virtually any other non-17aa oral.

Common Clones:
D-Plex by Competetive Edge Labs (CEL)
The ONE by Applied Nutraceuticals

“Effect of 1-alkyl substitution on the biological action in a series of androstanes.”
Cekan Z, Pelc B.
Steroids. 1966 Aug;8(2):209-18.
“Relative binding affinity of anabolic-androgenic steroids: comparison of the binding to the androgen receptors in skeletal muscle and in prostate, as well as to sex hormone-binding globulin.”
Saartok T, Dahlberg E, Gustafsson JA.
Endocrinology. 1984 Jun;114(6):2100-6.