Durham, N.C. — As people age, their muscles and bones get weaker. Duke University researchers say they may have found a drug to help slow the process.

Regular exercise is the best way to keep your bones and muscles strong, but exercise is difficult for many people, especially older adults.

“I jog, slowly, about a mile a day,” Tom Gallie said.

Gallie, 83, joined a Duke study that measured his ability during performance tests such as repeatedly standing up out of a chair without the use of his hands.

Participants either took a placebo or different doses of  experimental drug Capromorelin to stimulate the body's growth hormones.

“We've known for some time that growth hormone is involved in keeping muscles and bones strong. But as we age, growth hormone levels go down,” said Dr. Heidi White of Duke's Division of Geriatrics.

Lower levels of growth hormone can lead to frailty and limited mobility.

White says participants showed modest improvements in performance tests throughout the course of the two-year study.

“This was the first time that a compound of this type had been shown to increase, not only body mass – and lean body mass, meaning muscle mass – but also to make improvements in physical performance,” White said.

White says the results merit more research to determine whether the drug may help more seniors stay active and independent longer.

“That would be a great thing for old folks,” Gallie said.

As far as drug side effects, Capromorelin appears to stimulate appetite. Most study participants gained some weight.

Lean body mass – or muscle – may have increased and improved overall performance, but weight gain was a real concern that future research will have to take into account.