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man doing pushupsSteroids: Genobol Norbolethone is a steroid that is very similar to nilevar but instead of the standard methyl at position C-18 it instead has an ethyl group in this location. As a derivative of nandrolone this steroid is progestational but the addition of the ethyl group at C-18 adds to the already high progestational activity of nilevar making norbolethone a strong binder of the progesterone receptor. Norbolethone is also a bit more toxic to the liver than nilevar1. Norbolethone probably undergoes 5-alpha reduction to a less active metabolite in DHT target tissues and aromatizes in small quantities to estrogen derivatives. The anabolic to androgenic ratio for this steroid is very favorable and suggests that norbolethone is significantly stronger than nilevar in both its anabolic and androgenic effects. In fact, using norethandrolone as the standard, norbolethone is shown to be eight times as anabolic and three times as androgenic as norethandrolone. Norbolethone was originally developed and marketed by Wyeth under the trade name Genabol and was investigated for use in children with stunted growth at doses up to 2.5 mg per day2,3. It was not used widely by athletes until recently when it was used to evade drug tests due to its lack of detectability. When its use was discovered, norbolethone was used as a starting point in developing THG. Norbolethone delivers results similar to nandrolone with bloating and mass gains with less strength gains. Suppression of natural testosterone levels would be severe with norbolethone.




1. Bassan H, Kendler J, Harinasuta U, Zimmerman HJ: Effects of an anabolic steroid (Norbolethone) on the function of the isolated perfused rat liver. Biochem Pharmacol. Jul;20(7):1429-35, 1971

2. Gogate AN: Efficacy of norbolethone in stimulating linear growth in stunted children. Curr Ther Res Clin Exp. Jun;12(6):323-32, 1970

3. LeVann LJ, Cohn RE: Clinical evaluation of norbolethone therapy in stunted growth and poorly thriving children. Int J Clin Pharmacol. Apr;6(1):54-9, 1972


Adapted with permission from Seth Robert’s Anabolic Pharmacology, all rights reserved.