Exclusive | Biohackers and stars like Hailey Bieber are obsessed with this longevity molecule but is it the holy grail of supplements?

You know about DNA, but you may not have heard of NAD.You wouldn’t be alive without it.NAD — short for nicotinamide adenine dinucleotide — is critical for energy production, DNA repair and cell survival.

Scientists are investigating the potential for NAD+, the active form of NAD, to slow aging, boost brain health and increase disease resilience.“It’s not new, but the research around the longevity, health span of it has really exploded,” functional medicine practitioner Will Cole, who advises Gwyneth Paltrow and other celebs, told The Post about NAD.“I think that’s why you’re hearing more and more of it.”Because levels naturally decline with age, NAD+ tests, supplements and infusions have become big business.Here’s the 411 on NAD as it sweeps Hollywood, finding fans in Jennifer Aniston and Hailey Bieber.NAD is a coenzyme, which means that it helps other enzymes function.“It is vital for activating enzymes called sirtuins and PARPs — classes of enzymes involved in DNA repair, longevity and inflammation,” Daniel Puleston, an assistant professor of oncological sciences at the Icahn School of Medicine at Mount Sinai, told The Post.“For these reasons, NAD plays a fundamental role in humans and all other living organisms.”It’s essential for the production of cellular energy in the form of ATP.Longevity biomarker scientist Jin-Xiong She likens ATP to cellular gasoline.ATP is primarily produced in mitochondria, the “powerhouses” of cells.“If you don’t have enough NAD, your mitochondria don’t function efficiently,” She told the audience at a recent biohackers conference.“You don’t produce enough ATP, but you produce more free radicals that can damage your DNA, damage your cell membrane — and that’s one of the major causes of disease.”“Our two big sources of NAD are tryptophan, a protein product we can find in foods like red meat, dairy, poultry, nuts and beans, and some B vitamins,” Dr.

Ayodele Oyeyemi, a Northw...