Strange Steroids #1: Bolmantalate

The first of a series of articles on unusual and experimental steroids looks at the effects of adding an adamantoate ester to a steroid.

You’ll almost certainly have heard of steroid esters (such as acetate, propionate, enanthate, and cypionate), and likely understand that the duration of effect of the steroid is linked to the length of the ester. Longer esters increase fat solubility. This improved lipophilicity helps to keep the steroid in depots in the muscle tissue, delaying the release of the steroid into the blood stream, where esterase enzymes cleave the ester to yield the free alcohol steroid, which is the active form.

Chances are though, you haven’t heard of adamantoate esters. They’re based on the adamantane structure, a “diamondoid” shape made of four fused cyclohexane rings. The tetracyclic cagelike structure of adamantane is perhaps best illustrated visually:


The structure of adamantane was first theorized in 1924, first isolated from petroleum in 1933, and first synthesized in 1941. Since that time a number of adamantane derivatives have been explored. Drugs including the adamantane moiety typically readily cross the blood brain barrier, and include NMDA antagonists and antivirals. Two of the more interesting drugs are PF-877423 and bromantane.



PF-877423 is an amantadine-based investigational drug created by Pfizer. It’s a selective 11β-hydroxysteroid dehydrogenase type 1 inhibitor which was very potent in preventing adipogenesis in in vitro experiments. [1] For an introduction to 11β-HSD1 inhibition as a therapeutic target, see this blog’s earlier article.



Bromantane on the other hand is a Russian nootropic with both stimulant and anxiolytic properties. Like phenylpiracetam, it was first prescribed to cosmonauts and the military before finding its way into the hands of athletes who used it to circumvent doping controls. In fact, it can be considered one of the first “designer” doping agents, as a number of Russian and Lithuanian athletes tested positive for it at the 1996 Atlanta Olympic Games. [2,3]



In 1965 researchers from the pharmaceutical company Eli Lilly experimented with adamantoate esters of steroids such as testosterone, clostebol, norclostebol, nortestosterone, and masteron. [4] They theorised that the highly symmetrical adamantane ester would be lipophilic, and resistant to hydrolysis. Their experiments confirmed their suspicions, the 19-nortestosterone 17b-adamantoate in particular having a very long lasting anabolic effect, similar to nandrolone decanoate (deca-durabolin), but with only a remarkably small androgenic effect.

adamantoate kraay

J. Med. Chem. 8, 580–583

Eli Lilly named this 19-nortestosterone 17b-adamantoate “Bolmantalate”.

bolmantalate registered name

Despite never being marketed as an anabolic agent, and never appearing on the underground anabolic steroid market, Bolmantalate has been a scheduled drug in the United Kingdom since 1996, [5] and in the US it would be considered a controlled drug (as an ester of nandrolone) as a result of the passing of the Anabolic Steroid Control Act of 1990. [6]

[1] Bujalska, I.J., Gathercole, L.L., Tomlinson, J.W., Darimont, C., Ermolieff, J., Fanjul, A.N., Rejto, P.A., and Stewart, P.M. (2008). A novel selective 11b-hydroxysteroid dehydrogenase type 1 inhibitor prevents human adipogenesis. J Endocrinol 197, 297–307.
[2] Burnat, P., Payen, A., Le Brumant-Payen, C., Hugon, M., and Ceppa, F. (1997). Bromontan, a new doping agent. Lancet 350, 963–964.
[3] Thieme, D., and Hemmersbach, P. (2009). Doping in Sports (Springer) p236.
[4] Rapala, R.T., Kraay, R.J., and Gerzon, K. (1965). The Adamantyl Group in Medicinal Agents. II. Anabolic Steroid 17β-Adamantoates. J. Med. Chem. 8, 580–583.
[5] The Misuse of Drugs Act 1971 (Modification) Order 1996 2. (2)(b).
[6] Anabolic Steroid Control Act of 1990 (41)(A)(xlx).

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