Is trendy NAD supplement new fountain of youth? Here's what doctors say

LOS ANGELES -- A relatively new dietary supplement is getting a lot of buzz - it's called NAD.

Many influencers and podcasters are pushing the supplement - claiming NAD, which stands for nicotinamide adenine dinucleotide, can turn back the clock on aging - boosting energy, sharpness and strength. Preliminary research shows promise, but will it really work?

At The Vitamin Shoppe in Pasadena, on the highest shelf, you'll find sought after supplements store manager Gabriel Carranza says he can't keep in stock.

"We sell out pretty frequently, so every week we probably receive about three or four bottles, and they probably go within the two weeks that we get them," Carranza said.

So what is the buzz over NAD? Early science shows it may help boost longevity. Enthusiastic customers convinced 37-year-old Fredy Barroso of North Hollywood to try it himself.

"We're getting up there in age like we all are, and I heard good things about it," Barroso said.

Dr. Sarah Espinoza, director of Translational Geroscience at Cedars-Sinai, and her colleagues have been studying NAD, a coenzyme key to metabolism and cellular functions.

"We know that levels go down with age, and that there is an association with age-related diseases," she said.

Age-related diseases include dementia, diabetes and vascular conditions. Side effects may include headaches, fatigue, nausea and indigestion. Initial human studies focused on safety.

"There are no major adverse effects of taking it for relatively short periods of time like a few weeks. And it does increase NAD levels in cells in the blood," Espinoza said.

It was a small study, and while NAD levels increased, researchers didn't find any significant benefit in terms of a cognitive boost.

Some animal studies suggest that boosting NAD can improve mitochondrial function, insulin regulation and cognition, but those benefits have yet to be proven in human studies.

"We may show with future larger trials that there is benefit, but I would say at the moment, it's not recommended based on current evidence," she said.

To date, most of the research has been done on oral supplements, but the popularity of pricey NAD Intravenous infusions and injectables are growing. Espinoza said like the pills, there's no evidence that shows benefit.

Bottles of NAD can run between $20 to $150 per month depending on the brand and dosage. For Barroso, it's a small price for something he hopes will reap big benefits.

"You're trying to keep yourself young. You're trying to keep yourself healthy," he said.