BBC
OSLO-New research suggests that athletes who use steroids for a short period can benefit for their entire careers. Experiments with mice showed that a brief exposure to testosterone allowed the mice to rapidly regain muscle later in their lives. The scientist behind the study says that if a similar effect can be shown in humans, it should lead to a lifetime ban for dopers.
Norwegian scientists had previously published work that showed the existence of a “muscle memory”.  This suggested that if people exercised when they were young, their muscles grew more easily when they exercised later in life. The same team has now looked at the impact of a brief exposure to testosterone on mice.
They found three months after the drug was withdrawn, their muscles grew by 30% after six days of exercise. A control group of mice saw growth of just 6% in the same time period. “It is rare to have data that clear cut, I was pretty satisfied with that,” Prof Kristian Gundersen, from the University of Oslo, told BBC News. He explained that the drugs boost the number of cell nuclei in the muscle fibres.
These nuclei are key to building strength in muscles when people exercise and the mouse study suggests that these extra nuclei gained through using testosterone remain in the long term. Prof Gundersen believes the same holds true for humans. Despite the long held belief that steroid users lose the benefit of the drugs when they stop taking them, the Norwegian research suggests that even a brief exposure to steroids could have a long-lasting effect.