One study appeared to show that gw 50156 side effects included the growth of cancer cells but on further inspection, the results could be considered misleading. The study of gw1516 which was carried out on mice included 1000 times the recommended dose, taken over a prolonged period of time. As no individual would be taking such an inflated level of gw501516, there is debatable value attached to this particular study. Nevertheless, despite the criticism of this study, it was sufficient for GSK to drop the project so shouldn’t be dismissed completely.
In January 2004, Major League Baseball announced a new drug policy which originally included random, offseason testing and 10-day suspensions for first-time offenders, 30-days for second-time offenders, 60-days for third-time offenders, and one year for fourth-time offenders, all without pay, in an effort to curtail performance-enhancing drug use (PED) in professional baseball. This policy strengthened baseball's pre-existing ban on controlled substances , including steroids, which has been in effect since 1991.  The policy was to be reviewed in 2008, but under pressure from the . Congress , on November 15, 2005, players and owners agreed to tougher penalties; a 50-game suspension for a first offense, a 100-game suspension for a second, and a lifetime ban for a third.
Of concern to any user of Winstrol during a cycle should be its intoxicating effect on the liver . The drug is a 17aa structured steroid , meaning it has been structured in a way which allows it to be orally bio-available, yet this has the negative effect of making Winstrol potentially harmful to the liver. It is therefore paramount the duration of a Winstrol cycle is limited, the dose of the drug is not excessive, the user does not stack it with other hepatotoxic compounds, does not drink alcohol whilst on cycle, and does not use Winstrol if they have an underlying medical condition which effects the livers health. There are supplements available which also help protect the liver (Milk Thistle, Liv-52 etc), and these would be advisable during any Winstrol cycle .