Prohormone & Supplement Ingredients:

2,17a-methyl-5a-androsta-1-en-17b-ol-3-one (Methylstenbolone)

An active and orally-bioavailable compound engineered to resist metabolic breakdown on both the A and D rings, precisely where other active hormonal molecules typically degrade into estrogenic or biologically-inactive metabolites.

Claims: Sperior pharmacokinetic profile and exceptional potency; does not aromatize into any estrogenic compound and has no affinity for the progesterone receptor, so estrogen and progesterone receptor mediated side effects are of no concern.

AKA methyl stenbolone, methyl sten, 17a-methyl-stenbolone, m-sten, ultradrol

History:
In 1966, researchers at Searle Laboratories set about methodically testing the myotrophic (anabolic) and androgenic effects of a series of A-ring modified androstane derivatives. Compounds explored include
Methyl-1-testosterone (M1T), desoxymethyltestosterone (phera), 17a-methyl-1-androstenediol (Alpha One), and a variety of other 1- and 2-dehydro compounds were explored for activity.

The researchers announced that "Even the least active compound in Table 6 possessed a higher relative myotrophic potency than previously has been obtained with several clinically interesting compounds which have been studied under identical conditions, i.e. oxymetholone, oxandrolone, stanozolol, and methandrostenolone." (anadrol, anavar, winstrol, and dianabol).

Props to henryv, read the rest of his write-up at Total Flex Blog
Supplements with this ingredient:
2B-1 Pure Lean Mass (Prohormones)
Barbarian FX-Mass (Prohormones)
Msten Extreme Mass Builder (Prohormones)
M-Sten Rx (Prohormones)
Mutant Plexx (Prohormones)
Super DMZ Rx 2.0 (Prohormones)
Ultradrol (Prohormones)

Links to additional information on 2,17a-methyl-5a-androsta-1-en-17b-ol-3-one (Methylstenbolone)
Ultradrol aka Methylstenbolone (2,17α-dimethyl-5α-androsta-1-en-17β-ol-3-one) (Added on 4/13/2012)
Methylstenbolone (Added on 4/13/2012)
test results IDS mass tabs - ThermoLife International Forums (Added on 4/13/2012)
Antaeus Labs: A few words on the hepatotoxicity of 17a-methylated androgens/anabolics (Added on 4/13/2012)
Superdrol Replacement, Methly Sten (Added on 12/20/2012)
Methylstenbolone Explained (Added on 3/11/2013 6:28:00 PM)

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