NAD+ Supplements

NAD+ is sold in capsules, powders, nasal sprays and intravenous (IV) drips, often with the same promise: restore a molecule that fades with age. That’s a lot of delivery options for one molecule, and somewhere between the capsule and the IV bag it’s fair to wonder what each one has behind it. At Humanic Blue, we take those family members one at a time: NAD+ supplements include related vitamin B3 compounds with different evidence records.

Here’s the short answer. NAD+ is a molecule cells need for energy metabolism. A study that measured muscle NAD+ at a single point in time found lower NAD+ in older adults than in young adults, with the lowest levels in a small group of physically impaired older participants. Because it took one-time measurements, it cannot show that aging or exercise caused those differences. Oral nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) can raise NAD-related measures in blood, but clinical benefits remain inconsistent or absent. Nicotinamide reduced skin cancers in one specific high-risk population, not aging generally. A 2026 systematic review found no eligible outcome trials of intravenous or intramuscular NAD+ for anti-aging or wellness. For living longer and better, no NAD+ product has been shown to extend human life.

Why does NAD+ get attention?

In the Amsterdam study in Nature Aging, researchers compared muscle samples from young adults with samples from older adults who were exercise-trained, normally active or physically impaired. Muscle NAD+ was lower across the older groups, lowest in the physically impaired group and more preserved in the trained group. NAD+ also tracked with daily steps and measures of muscle function.

Those were cross-sectional associations, not an exercise intervention. They cannot tell us whether training preserved NAD+, whether higher NAD+ supported activity, or whether another difference affected both. Exercise has broad evidence-based health benefits, but this study alone does not prove that exercise raises muscle NAD+. Why mitochondria and exercise matter is covered in Mitochondrial Health and Aging.

The NAD+ family

Form	What the evidence shows	The catch
Nicotinic acid (niacin)	A vitamin and older cholesterol drug	Extended-release niacin plus laropiprant failed to reduce major vascular events and increased serious adverse events in a large trial; the trial cannot assign every effect to niacin alone
Nicotinamide	Reduced skin cancers in high-risk people in one trial	No reduction demonstrated in an early-stopped transplant-recipient trial; uncertainty remains and no aging benefit is established
Nicotinamide riboside (NR)	Raises blood NAD+ in multiple randomized trials	No clear improvement in insulin response or muscle outcomes
Nicotinamide mononucleotide (NMN)	Raises NAD-related blood measures	Two small, short direct comparisons with NR produced conflicting estimates; clinical benefits remain unproved
Oral NAD+	Marketed directly	Human outcome data weren’t found in the 2026 review
IV NAD+	Offered by clinics	No eligible outcome trials for anti-aging or wellness; FDA has warned about adverse reactions and endotoxin contamination in compounded injections

Niacin: the old cholesterol drug

Niacin was long used to improve cholesterol. In HPS2-THRIVE, adults with blood-vessel disease received extended-release niacin plus a second drug, laropiprant, or placebo for a median of 3.9 years. Major vascular events occurred in 13.2% and 13.7% of participants, respectively, a nonsignificant difference. The combination increased serious problems with diabetes control and diagnoses of diabetes, as well as serious gastrointestinal, musculoskeletal, skin, infection and bleeding events. Merck funded the trial. Because the treatment contained two drugs, the trial does not establish that niacin alone caused every adverse event. It does show that improving lipid biomarkers with this niacin-containing regimen did not translate into fewer major vascular events.

What has nicotinamide shown?

In the ONTRAC trial, adults without immune suppression who had experienced at least two nonmelanoma skin cancers during the previous five years received 500 mg of nicotinamide twice daily or placebo for 12 months. The rate of new nonmelanoma skin cancers was 23% lower during treatment. The benefit was no longer evident during the six months after treatment stopped. In a separate 2023 trial of organ-transplant recipients, the same dose did not reduce keratinocyte cancers, another term for these nonmelanoma skin cancers, over 12 months. That trial stopped early because recruitment was inadequate, limiting its precision. This is a specific prevention question for a dermatologist, not evidence that nicotinamide slows aging.

What limits the transfer of a skin-cancer trial finding to a general claim about aging?

NR and NMN: raising the number

Both can raise NAD-related measures in blood, but even the direct comparisons are unsettled. A 14-day study in healthy adults, in which participants knew which treatment they received, found similar increases with 1,000 mg a day of NR and NMN. A separate, much smaller open-label crossover, in which healthy adults tried each compound, used 1,200 mg a day for eight days per treatment and found a larger blood response to NR, without a significant difference in brain NAD+. Neither study tested whether people lived longer or functioned better. A 24-week placebo-controlled NMN trial in adults 65 and older raised NAD-related metabolites but did not improve its primary hearing or physical-performance outcomes. The details are in NMN for Longevity and NR vs. NMN.

What do trials show about IV NAD+ drips?

IV NAD+ is offered by wellness clinics, but the clinical evidence has not caught up with the marketing. A 2026 systematic review covered 113 studies, including 33 human studies and 80 rodent studies. It found no eligible clinical-outcome trials of intravenous or intramuscular NAD+ itself for anti-aging or wellness; an IV NAD+ study described how the body processed it rather than showing a health benefit.

There is also a current product-safety issue. FDA has warned that some compounders used food-grade NAD+ ingredients for sterile injections and that it received reports of severe chills, shaking, vomiting and fatigue after NAD+ injectables, with some patients needing medical treatment. In a January 2026 warning letter, FDA described three patients who developed low blood pressure, uncontrollable shaking, shivering and body aches after compounded NAD+ from one lot; testing found excessive bacterial endotoxin, a contaminant from bacteria. These reports do not show that every compounded product is contaminated, but they make the safety and sourcing of an unproved infusion consequential.

What evidence would distinguish an IV NAD+ marketing claim from a demonstrated clinical benefit?