It's a sad fact that past the age of about 35, we begin to progressively lose muscle mass. This can be somewhat offset through exercise, although most people still generally tend to get weaker as they get older. A new drug could help, as it's been shown to increase muscle size and strength in elderly mice.

The experimental medication is being developed by researchers from The University of Texas Medical Branch at Galveston.

Basically, they identified a protein in muscle stem cells (which become muscle cells) that is apparently responsible for their age-related dysfunction. The scientists then produced a drug that minimizes the effect of that protein, allowing aged muscle stem cells to revert to a more youthful state in which they still readily form/repair muscle.

The protein is known as nicotinamide N-methyltransferase (NNMT), so the drug is appropriately enough called NNMT inhibitor (NNMTi).

In lab tests, one group of old mice with a muscle injury received daily doses of NNMTi, while another group got a placebo. After seven days of treatment, it was found that animals from the first group had a higher number of functional muscle stem cells, which were repairing the injury. Those mice also doubled their muscle fiber size, and had 70 percent more muscle strength than the placebo mice.

The blood chemistry of both groups remained about the same – according to the researchers, this suggests that the medication wasn't causing any negative side effects.

"There are no treatments currently available to delay, arrest or reverse age-related muscle degeneration," says Dr. Harshini Neelakantan, senior author of a paper on the study. "These initial results support the development of an innovative drug treatment that has the potential to help the elderly to become fitter, faster and stronger, thus enabling them to live more active and independent lives as they age."

The paper was published this week in the journal Biochemical Pharmacology.