The first time I heard mention of NAD (pronounced “nad” not “N-A-D” by its evangelists) it was from the mouth of Joe Rogan. Ergo, I eye-rolled and moved on with my life. But then it started popping up in my social feeds. It was being used as a verb (excuse me, you’re what-ing?) on podcasts that I actually like, and it was being name-dropped (or, ahem, NAD-dropped) by humans whose opinions I value. At a skin care event in New York, makeup artist and newly minted, sleep-deprived mom of two Jessi Butterfield shared that she had started taking it after hearing whispers of its brain fog-lifting abilities from some of her male grooming clients who used it for performance. “I feel like the NAD has helped me regain a little more mental clarity and my overall energy level has definitely improved compared to after my first kid,” she told me. My interest was piqued.
NAD (or nicotinamide-adenine dinucleotide) is an energy-stoking coenzyme that’s found naturally in the body. It bounces around in our cells involving itself in hundreds of metabolic processes. The NAD these finance bros, biohackers (and the podcasters they listen to), and more than one reality star are usually referring to are NAD IV therapy drips. (Rogan has also said he takes his NAD in the form of an NMN supplement; more on that later). “I’m going to NAD for the rest of my life and I’m never going to age,” Hailey Bieber said in an oft-referenced 2022 episode of Keeping Up with the Kardashians.
Rich guys in fleece vests have never had any sway over my decision making, and I try to pay as little attention as humanly possible to anyone Kardashian related or adjacent (particularly if they are under the age of 40 and doling out advice about aging), but 55-year-old Jennifer Aniston has also repeatedly mentioned NAD and I’ve heard a number of anecdotal reports from friends and colleagues in their forties and fifties who, like Butterworth, had experienced an energy boost after literally hooking themselves up. So, in the name of research and the teensy possibility that my depleted brain and body could experience some kind of system reset, I did the same.
Why would I, in my mid-forties, need to boost my NAD? NAD has two primary functions in the body: cellular energy production and cellular and DNA repair. And, much like our collagen, the NAD our body naturally produces starts a precipitous decline by our twenties, debilitated by our lifestyle choices and daily stressors (poor diet, not enough exercise, stress, pollution and so on), dipping steadily with age. When those levels drop, you might start to feel more fatigued or experience mood swings or poor sleep. The idea behind supplementing with NAD is that you are, in theory, filling up the proverbial tank.
“It’s giving you back a molecule that you had when you were younger which we believe is responsible for keeping the cells optimized, particularly the mitochondria, the cell powerhouse,” says Amanda Kahn, MD, a board-certified internist who offers NAD injections in her office. Mitochondria, and a desire to keep them healthy (read: young) has become a central talking point in the longevity conversation: When they slow down, that’s a sign that cells are working less efficiently, following a pathway called senescence, says Dr. Kahn. This can have a cascading effect on other surrounding cells, with cellular aging being almost contagious.
Online (and on reality TV), NAD has been dubbed the fountain of youth—but many people who choose to supplement with it regularly are less interested in the abstract extension of life or suspension of beauty and more focused on health-related goals like boosting immunity so they can better stave off illness (pre-clinical studies have shown that NAD helps prevent or reduce T-cell exhaustion in mice with sepsis), to manage pain or inflammation, to support metabolic health, to avoid weight gain or insulin resistance, and to improve energy and cognitive function (it me!). But though the Biebers make it look easy, NAD—both the various forms it’s offered as and the scientific research around it—is not so straightforward.
There are two main ways to take part in NAD therapy. You can take NAD itself in the form of NAD+ or NADH (essentially two forms of the same molecule, the only difference is that NADH is bound to a hydride, a hydrogen atom with an extra electron, which helps form a transport chain), or you can take a NAD precursor (NMN and NR are the most common) which helps the body produce its own NAD. In 2022, the US Food and Drug Administration (FDA) declared the use of NMN in supplements to be unlawful under DSHEA (Dietary Supplement Health and Education Act), because it was previously studied as a drug, which makes it off limits for use in over-the-counter supplements or food.
The Natural Products Association, a DC-based trade association, filed a citizen petition challenging the FDA’s position that NMN and, in October, the courts issued a joint motion to stay the case, meaning the FDA cannot crack down on NMN use in supplements for the time being. The FDA is expected to answer the petition by the end of July, which could potentially greenlight the use of NMN in dietary supplements beginning this year.
But regardless of the legal standing of this NAD precursor, doctors are more broadly divided on what form of NAD is optimal, how said supplement should be administered for maximum absorption, and whether supplementation is effective (or safe) in humans at all. Andrew Ahn, MD, a physician researcher at Brigham and Women’s Hospital and the Osher Center for Integrative Health at Harvard Medical, has not prescribed or even suggested any form of NAD supplementation to his patients, whom he says also haven’t been asking for it in the first place.