NAD+: Hope, Hype, and What the Science Says It’s being called the secret to better energy, longer life, and even enhanced fertility. But what exactly is NAD — and why is everyone suddenly talking about it? In the world of wellness, NAD has become the latest molecule to wear the crown. Celebrities are dripping it into their veins. Longevity experts are stacking it with supplements. Clinics are charging thousands for access to it. And yet... most people still don’t know what it does.