NAD+ supplements and 'cellular energy': what the science says

What did @holisticglpgirly actually say?

The creator calls NAD "the ultimate anti-aging, longevity, DNA repair, cellular repair, peptide" and claims it delivers "better clarity, better sleep, more energy, boosted metabolism, and fat burning." She also says NAD levels naturally decline after age 30, recommends stacking with NMN as a precursor, and frames the whole thing as something that will help you "live longer, age in reverse, look better, and feel better."

There is a lot packed into a short video. Some of it reflects real science. Some of it is inflated. And one foundational claim, that NAD is a peptide, is just incorrect, and that error matters more than it might seem.

Does the science back this up?

Partially, but the research is less settled than the video implies. NAD+ is a real and well-studied coenzyme involved in energy metabolism, DNA repair, and cellular signaling. The decline with age is documented. The therapeutic potential is genuinely interesting. But human trial evidence for most of the specific benefits claimed is still thin.

What the research actually shows: NAD+ levels do decline with age, a finding supported by Yoshino et al. (2018, Cell Metabolism), who demonstrated this in skeletal muscle tissue. NMN supplementation has been shown to raise NAD+ levels in humans in small trials, including Yoshino et al. (2021, Science), which found improvements in muscle insulin sensitivity in postmenopausal women. However, that trial was 10 weeks, 25 participants, and focused on a specific metabolic outcome, not broad anti-aging effects. A 2023 randomized trial by Yi et al. in GeroScience found NMN raised NAD+ blood levels but did not produce statistically significant improvements in physical performance or body composition. The bold claim that this peptide helps you "live longer" has no human clinical backing.

What did they get wrong (or right)?

Let's start with the wrong, because it is significant. NAD is not a peptide. It is a coenzyme, a small molecule derived from niacin (vitamin B3). Peptides are short chains of amino acids. These are fundamentally different categories of molecules, with different mechanisms, different regulatory pathways, and different delivery considerations. Calling NAD a peptide is not a minor slip. It could lead someone to think they are buying a compounded injectable peptide when they may be getting something else entirely, or vice versa.

The claim that "our body already creates it, so when we take NAD, we make more of it" is also muddled. Oral NAD+ is largely broken down in the gut before it reaches cells. The NMN-first tip actually gestures at this problem, since NMN is a precursor that survives digestion better. That part, the precursor logic, is scientifically reasonable, though the evidence for dramatic results remains limited. The age-30 decline claim is broadly supported by research, so credit where it is due.

What should you actually know?

NAD+ is a legitimate area of longevity research, but it is nowhere near the "ultimate" solution the video frames it as. The human trial data is early-stage, mostly small, and often funded by supplement companies. That does not mean the research is worthless. It means the headlines are running well ahead of the science.

If you are considering NAD+ or NMN supplementation, a few things are worth knowing. First, delivery method matters significantly. Oral bioavailability of NAD+ itself is poor. NMN and NR (nicotinamide riboside) have better absorption profiles. Second, intravenous NAD+ infusions, which are a separate category entirely, have different pharmacokinetics and are used clinically in some contexts, but that is not what most people are buying from wellness creators. Third, "anti-aging" and "age in reverse" are not outcomes that any supplement has demonstrated in peer-reviewed human trials. Longevity research is genuinely promising, but no product has cleared that bar yet. A telehealth provider or physician can help you evaluate whether NAD+ precursors make sense for your specific situation.