Methenolone is a synthetic derivative of dihydrotestosterone that is commonly known by the trade name Primobolan. The acetate ester version is taken orally though their used to be an injectable version of this ester in the past.
A highly overlooked steroid, many people do not consider primobolan to be very effective and coupled with its high price, many do not consider it to be worthwhile. The oral form of methenolone acetate is relatively weak due to the fact that methenolone is not 17-alpha alkylated. Instead, the 1 methyl group seems to offer some protection from metabolism to 1 and 2 hydroxy metabolites. Even so, the acetate does not have great oral bioavailability and a pretty high dose is needed to see significant effects.
Since it is a DHT derivative, methenolone does not aromatize nor does it have much progestational activity. In fact, being a DHT derivative, primobolan likely acts as an aromatase inhibitor to some degree which likely contributes to its reputation as a dry gainer with less suppressive effects. Since it is already 5-alpha reduced, it does not get metabolized by 5-alpha reductase. Methenolone still undergoes metabolism by 3-alpha hydroxysteroid dehydrogenase in skeletal muscle but less so than DHT1.
This results in a molecule that is somewhat less potent but still has a decent anabolic to androgenic ratio. Furthermore it binds only moderately to SHBG and there is no evidence that methenolone interacts to any degree with the glucocorticoid or progesterone receptors2. Primobolan does not bring on massive weight gains, but this is due to the fact that there is very little water and fat accumulated. Primobolan is used for adding quality mass with little to no side effects but the injectable version is much preferred over the oral version. Low doses of primobolan have been used by women with minimal side effects. Effective doses for men are considered to be 100-150 mg per day with women taking 25 to 50 mg.
Some have argued that primobolan can be used without shutting down natural testosterone production. While suppression will be reduced with this steroid because it does not convert to estrogen, there will still be some reduction in testosterone production that will become worse as higher doses are used. A little known fact about methenolone is that it has been shown to have similar levels of efficacy as oxymetholone for elevating red blood cell count3. Methenolone, either the tablets or the injectable, has never been as available as most of the other stand-bys and is often expensive when it is found. There are only a few pharmaceutical preparations available and these items are often scarce even from black market sources.
1. Schanzer W: Metabolism of anabolic androgenic steroids. Clin Chem. Jul;42(7):1001-20, 1996
2. Saartok T, Dahlberg E, Gustafsson JA: 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. Endocrinology. Jun;114(6):2100-6, 1984
3. Gorshein D, Murphy S, Gardner FH. Comparative study on the erythropoietic effects of androgens and their mode of action. J Appl Physiol.
Adapted with permission from Seth Robert’s Anabolic Pharmacology, all rights reserved.