The research is part of a fast-growing field of study aimed at finding ways to combat age-related frailty and diseases. Getty Images

It’s not the Fountain of Youth just yet, but a new study led by researchers from Harvard and MIT might offer important clues in the quest to reverse the effects of aging.

As people age, their blood vessels lose the capacity to deliver oxygen and nutrients to muscles, resulting in loss of endurance, said David Sinclair, a professor of genetics at Harvard Medical School and a senior author of the study.

In the report, published Thursday in the journal Cell, the researchers said mice treated with a naturally occurring compound had shown signs of blood vessel growth. The compound, called nicotinamide mononucleotide, or NMN, strengthens metabolism, cardiovascular functions, and cell maintenance.

The researchers said that after 18-month-old mice were treated with NMN for two months, they experienced a 56 percent to 80 percent boost in endurance. These effects were also seen in mice that were 32 months old — comparable to humans in their 80s.

It’s too soon to expect any benefits for humans. The team is in the first stage of a trial that is testing NMN in people.

The research is part of a fast-growing field of study aimed at finding ways to combat age-related frailty and diseases.

Sinclair believes NMN could not only restore energy and vitality in humans but also increase their life expectancy.

“It’s definitely going against the natural process of aging, which I think is one of the most important things humans need to work on, just like working against cancer or Alzheimer’s,” Sinclair said. “It could have a big effect on increasing lifespan in a healthy way.”

He emphasized that ideally, exercise alone would prevent age-related muscle loss, but that’s not always realistic for some people. And from there, he said, it’s a vicious cycle.

“If people don’t exercise, they lose abilities to move as easily, and when then lose abilities, they can’t exercise,” he said.

Nir Barzilai, director of the Institute for Aging Research at Albert Einstein College of Medicine in New York, said the research is encouraging but faces significant challenges.

“The fact that it works on mice is promising, but you really don’t know the safety of those drugs,” said Barzilai, who has led anti-aging studies. “And I think it’s important to get an FDA approval to treat aging in order to actually start developing it as a drug, and then we’ll know what we’re doing.”

The new study is not the first time Sinclair has announced an antiaging advance. He stirred hope with his work on resveratrol, an ingredient in red wine and cocoa that he believed could lengthen people’s lives. But other scientists have questioned the substance’s effects.

GlaxoSmithKline, which bought a company cofounded by Sinclair, halted research on resveratrol.