Evidence at a glance
Human clinical evidence 1 of 3 (limited), preclinical evidence 3 of 3 (substantial).
My read of the published evidence, not a rating of whether it works. Preclinical findings cannot establish human benefit.
What is NAD+?
A confession first: NAD+ is not a peptide. Nicotinamide adenine dinucleotide is a coenzyme, a small molecule that every cell in your body uses thousands of times a second to shuttle electrons during energy production. It earns its place in this section because it is sold through the same clinics and vendor sites, in the same IV bags and vials, to the same audience.
The biology is foundational, Nobel-adjacent stuff: NAD+ sits at the centre of converting food into ATP, and serves as fuel for enzymes that repair DNA and regulate cellular stress responses. Tissue NAD+ levels appear to decline with age in animals and, by more limited evidence, in humans. That single observation is what an entire industry has been built on.
Why researchers are interested
Beyond its electron-carrying day job, NAD+ is consumed, literally used up, by enzymes with starring roles in aging biology: sirtuins, which regulate metabolism and stress resistance; PARPs, which repair damaged DNA; and CD38, an enzyme that degrades NAD+ and becomes more active with age and inflammation. An aging tissue may face rising NAD+ consumption against flat production, draining the pool exactly when repair demand peaks.
The therapeutic logic follows: restore NAD+ and you restore the budget for repair and metabolic regulation. In old mice, boosting NAD+ through precursors improved various measures of tissue function. Whether the same lever moves anything that matters in aging humans is the question the field keeps circling.
Regulatory status
It depends on the product and the route. Oral precursors, nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), are sold as supplements; in Canada, natural health products require licensing, and the permitted status of specific ingredients has shifted over time (NMN's U.S. status has been contested as well). IV NAD+ drips occupy a murkier space: offered by wellness clinics under practitioner discretion, but no NAD+ infusion product is an approved therapy for aging, energy, or addiction recovery. Injectable vials from peptide vendors are unauthorized products, full stop.
What human research shows
Human trials have mostly tested oral precursors, not NAD+ itself. They show reliably that NR and NMN raise blood NAD+ levels. Pharmacologically, the lever works. What the trials have not shown is that pulling the lever improves hard outcomes: studies of insulin sensitivity, muscle function, and cardiovascular markers in generally healthy or overweight adults have produced mixed, mostly modest-to-null results. Some small studies report isolated positives, blood pressure here, muscle speed there, awaiting replication.
For IV NAD+, the evidence is thinner still: infusion pharmacokinetics and small uncontrolled reports, with no rigorous randomized trials supporting the energy, clarity, or recovery claims on clinic menus. Raising a molecule's blood level is not a health outcome.
What early research shows
The preclinical case is genuinely strong, which is what keeps serious scientists engaged. In aged mice, NAD+ restoration has improved mitochondrial function, vascular health, muscle endurance, and stem-cell activity across many independent labs. Mechanistic work ties NAD+ availability to DNA repair capacity and sirtuin activity. But mice are short-lived creatures in which many interventions shine, and the translation record from mouse aging biology to human trials is, so far, humbling. Animal data justifies the human trials now underway; it cannot pre-empt their results.
What it's being studied for
The NAD+ clinical research programme is unusually broad for the supplement aisle. Researchers are investigating:
- Age-related metabolic decline and insulin sensitivity
- Muscle function and physical performance in older adults
- Neurodegenerative conditions, including Parkinson's disease
- Cardiovascular and vascular aging markers
- DNA-repair capacity and cellular stress resilience
- Recovery contexts, including chemotherapy-related nerve outcomes
What remains uncertain
The central unknown is embarrassing in its simplicity: does raising NAD+ improve human healthspan at all? Beyond that sit layered questions: whether oral, injectable, or IV routes deliver NAD+ where it matters (cells largely build their own from precursors rather than importing it whole), what long-term supplementation does, and a theoretical concern the field takes seriously: rapidly dividing cells, including cancers, are hungry consumers of NAD+, and whether boosting it is uniformly safe over decades is unresolved.
IV and injectable products add the usual grey-zone issues: unverified formulations, infusion-site reactions, and clinic claims running far ahead of data.
What people report
NAD+ drip testimonials are among wellness culture's most vivid: surging energy, mental clarity, hangovers erased. The infusion experience itself is intense. Rapid drips commonly cause chest tightness and nausea, which is why they run slowly. An intervention you can *feel* is an intervention primed for placebo response. You paid several hundred dollars, sat in a lounge chair for two hours, and felt something happen. Of course the afternoon felt different.
Oral precursor users report subtler effects: better energy, better sleep, the same soft outcomes that move with any new health routine. None of this distinguishes the molecule from the ritual. For that, we wait on the trials.
