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Silabolin, the forgotten Russian nandrolone

Once upon a time in a faraway place we found an interesting article. It was written by Russian researchers in the early eighties and is a brief summary of Russian research on an unusual steroid with unusual properties. The anabolic steroid is called silabolin.

The active ingredient in silabolin is not an ester but a nandrolone ether: to be precise, a trimethylsilyl ether of 17alpha-methyl nandrolone. In the body, acids cut the silicium atom off from the oxygen atom. This process is probably quicker than the one in which the body cuts the fatty acids off nandrolone esters, although we don't know for sure.

Silabolin first appeared in the Russian scientific literature in 1965. Researchers stumbled across it when they were looking for a steroid hormone with maximum anabolic and minimum androgenic characteristics.

The writers of the article one of whom probably is the inventor of silabolin describe animal experiments in which they compare silabolin with testosterone-propionate, phenobolin (that's durabolin, or nandrolone-fenylpropionate) and retabolin (that's deca-durabolin or nandrolone-decanoate). The table below shows the results of the experiment.

Silabolin, the forgotten Russian nandrolone

At first glance it appears that retabolin/nandrolone-decanaoate is a more powerful steroid than silabolin. But, say the researchers, look at what happens to the androgenic and anabolic effect of silabolin if the dose increases. The androgenic effect remains constant but the anabolic effect increases. This doesn't happen with the other anabolic steroids.

In longer animal experiments, the researchers discovered that the anabolic/androgenic ratio of silabolin was greater than that of the other two 19-nor-androgens.

The authors also refer to the results of human studies in their article. Silabolin was given in doses of 50-100 mg per week for four consecutive weeks to patients recovering from heart operations and to TB patients. Judging by these experiences, the researchers state that the androgenic effects of silabolin are nil.

Every now and then silabolin preparations appear on the black market. They are supposed to be especially effective and safe for women.

The new products probably no longer contain the curious substance that the Russians put in their products. Going by the photo here, the current silabolin preparations contain ethylestrenol. According to a thread that appeared on 12/8/2004 on, the stuff that's on the market now comes from underground workshops. [ 08-12-2004]

Pharmaceutical Chemistry Journal Volume 20, Number 2, February 1986, 143-148.