They used a chemical to rejuvenate muscle in mice and said it was the equivalent of transforming a 60-year-old's muscle to that of a 20-year-old — but muscle strength did not improve. Their study, in the journal Cell, identified an entirely new mechanism of ageing and then reversed it. http://www.cell.com/retrieve/pii/S0092867413015213
Other researchers said it was an "exciting finding".
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