Winstrol is hepatotoxic, and because of this, it should be used at the lowest effective dose for the shortest possible cycle. What’s more, you should consider using a supplement designed to provide some additional protection. Milk thistle is a highly recommended option; studies suggest it can provide an effective layer of protection when it is used for the entire length of your cycle. There are some other supplements on the market, such as Liver Care, which are blends of natural ingredients that have been shown to work together to prevent liver toxicity.
Stanozolol appears to offer less hepatic stress than an equivalent dose of Dianabol (methandrostenolone). Studies giving 12mg of stanozolol per day for 27 weeks failed to demonstrate clinically-significant changes in markers of liver function, including serum aspartate amino-transferase, alanine amino-transferase, gamma-glutamyltransferase, bilirubin, and alkaline phosphatase. 621 Relative hepatotoxicity increases as the dosage escalates, so hepatic dysfunction should still be a concern. In rare instances, high doses (alone or in combination with other steroids) have been implicated in cases of serious life-threatening hepatotoxicity in bodybuilders. Injectable stanozolol has also been implicated in severe hepatotoxicity in an otherwise healthy bodybuilder, 622 and should not be used as an alternative medication when liver toxicity precludes oral stanozolol use.