Shannon Sharpe

Hall of Famer Shannon Sharpe is 50, but his body is still ripped, as he has shown on his Instagram account. A big part of Sharpe's regimen these days is CrossFit, which he enjoys because of the competitive aspect with others at the gym.

"I got kids older than they are, and they can't keep up with me -- that makes me feel good," Sharpe says. "Makes me want to go back again tomorrow. See them again the next day, and beat them again."

Getting to the gym isn't always easy. His job as a media commentator means waking up daily at 3 a.m. But he's motivated to keep winning so nobody from his gym can talk trash about him to their friends. 

In addition to paying attention to his diet, Sharpe says Tru Niagen gives him an edge in maintaining his condition. The clinically studied supplement boosts levels of a molecule called NAD, which is a lot easier to remember than its formal scientific name of Nicotinamide Adenine Dinucleotide.

Now everyone has NAD in all of their cells. But your levels of NAD, which contribute to basic functions like sleeping, breathing and eating, can drop by half between ages 40-60. That's where Tru Niagen comes into the picture for Sharpe, who cites the "get-up-and-go" it provides.

"I don't like it -- I love it," Sharpe says.

And the mirror doesn't lie: