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Ariel Poler is a veteran angel investor who spends his days traveling around the Bay Area to meet with entrepreneurs. Now in his early fifties, he also thinks a lot more about his own health, so he makes an effort to keep his stress levels low by eating well and taking regular kite-surfing trips. But he also takes a tiny, white pill called metformin, which is prescribed to millions of people with diabetes to help control high blood sugar. Poler does not have diabetes, but he takes it for a different reason. He hopes that it will help keep him healthier for longer. Unlike some in Silicon Valley, who are increasingly investing in wonder drugs and starting companies to crack the code on aging, Poler isn't planning to live forever. But he does believe that his metformin use, coupled with his commitment to nutritious food and exercise, will help delay the onset of serious health issues. "Maybe I won't get cancer until later, like 85 instead of 83," he says with a shrug. He's not alone. Metformin is undergoing a bit of a renaissance in Silicon Valley tech circles -- among people who do not have diabetes. CNBC interviewed a dozen executives and investors working in the tech industry who take the drug as a hedge against aging. Some were willing to speak publicly about it, while others preferred to remain anonymous as they did not want their employers to find out. Bolstering their case, there are also some high-profile supporters in the medical field, including the renowned aging researcher Nir Barzilai. WATCH: Diabetics are hacking insulin pumps

Mixed reviews

Metformin is not a new innovation. The drug, which is available in generic form for about 5 cents a pill, has been around for decades. But in recent years, researchers have studied the long-term effects and found that diabetics who took it for years wound up experiencing unintended health benefits, including a reduced cancer risk compared to the general population. Further studies of the drug in mice showed evidence of an improved life span.