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Like most oral steroids methandrostenolone is 17-alpha-alkylated so that it can't be broken down into a 17-ketosteroid, and therefore rendering the substance ineffective. However, this causes liver values to become elevated over a short period of time. It is for this reason that long-term use of any 17-alpha-alkylated steroid is considered dangerous. Despite this however, no long-term damage should be expected if use is kept to relatively short periods, with liver values returning to previous levels after use is discontinued in nearly all cases (4).
It should also be noted that methandrostenolone may be less useful to those competing in aerobic events as it also diminishes cell respiration(5). This may inhibit an individual's ability to perform at their maximum capacity.