NAD+, NMN and Nicotinamide Riboside: What Research Shows

Overview

NAD+ (nicotinamide adenine dinucleotide) is a molecule that many of the body's metabolic reactions depend on. [1] A 2026 systematic review notes that NAD+ levels decline with age, which led to interest in "NAD+ boosting." [2] Two related compounds, NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside), are building blocks the body can use to make NAD+. They are sold as supplements. In some wellness settings, NAD+ is also given by injection or infusion. [2] This page is education only; it gives no amounts and no advice to start or stop anything.

Evidence labels used here: approved medicine, established, promising but limited, mixed, insufficient evidence, preclinical (cells or animals only), no good evidence of benefit, evidence of harm, marketing claim.

NAD+

• What it is. A cofactor (helper molecule) for many enzymes. Raising it in the blood is not the same as improving health.
• Supplements and infusions. The 2026 review of 33 human studies found no eligible outcomes trials of intravenous or intramuscular NAD+ itself for anti-aging or wellness. [2] Label for IV NAD+ for anti-aging: insufficient evidence.
• Oral NAD+. Proper evidence not found in the sources checked for this page (we looked at systematic reviews and trial reports on PubMed).

NMN

• Animal findings. In rodents, NAD+ raising was often linked to better metabolic, mitochondrial and inflammatory results, though effects varied. [2] Label: preclinical.
• Human trials. A 10-week placebo-controlled trial in postmenopausal women with prediabetes who were overweight or obese found muscle insulin sensitivity improved with NMN versus placebo. [3] A 2026 meta-analysis of randomized trials found no clear effect on body weight, blood sugar, lipids or systolic blood pressure, with small signals in diastolic blood pressure that need confirming. [4] Another meta-analysis found NMN did not improve muscle mass or function in adults over about 60. [5] Label: promising but limited for specific metabolic questions; insufficient evidence for slowing aging.
• Safety. In 10 trials, NMN did not increase adverse events, serious adverse events or liver enzyme levels over days to 24 weeks. The authors call long-term safety unconfirmed. [4]
• US regulatory status. In 2022 the FDA took the position that NMN was excluded from the dietary supplement definition because it had first been authorized for investigation as a drug. In a response to a citizen petition (docket FDA-2023-P-0872), the FDA reversed that view in 2025: it concluded NMN is not excluded, citing evidence NMN was marketed as a supplement in the United States as early as 2017, before the drug authorization. [6][7] Separately, the FDA says supplement firms must evaluate the safety and labeling of their products before marketing, and that the FDA can act on products after they reach the market. [8] The agency also noted that its acknowledgment of a safety notification is a procedural step, not its own finding that the ingredient is safe. [6] Regulations elsewhere were not verified for this page, and laws change; this is not legal advice.

Nicotinamide riboside (NR)

• Healthy adults. In a 2018 crossover trial in healthy middle-aged and older adults, NR was well tolerated and raised NAD+ metabolism; the authors suggested future trials look at blood pressure and arterial stiffness. [9]
• Blood NAD+ is not a health outcome. In people with mild cognitive impairment, a 12-week pilot found blood NAD+ doubled with NR but cognition did not improve. [10]
• Parkinson disease. A 2026 JAMA phase 3 trial in 410 people with early Parkinson disease found that 52 weeks of NR did not improve outcomes and was associated with slightly worse scores than placebo; the authors concluded it is not supported as a disease-modifying treatment. [11] Label: no good evidence of benefit in that condition; this does not prove harm in healthy people.
• Older adults' muscle. The muscle meta-analysis found NR did not support preserving muscle mass or function in people over about 60. [5]

Comparing the three

The 14-day comparison in 65 healthy adults found NR and NMN raised circulating NAD+ similarly, and suggested gut bacteria may play a role in how they work. [1] The 2026 review concluded that NAD+ boosting shows clear biological activity but its clinical effectiveness for anti-aging or wellness remains inconclusive. [2]

Who should check first

Ask a clinician before any NAD-related product if you are pregnant or breastfeeding, have a medical condition (including Parkinson disease or diabetes), take medicines, or are scheduled for surgery. Supplement quality varies; see product quality and contamination and how supplements are regulated. For a plain-language look at marketing, read NAD, NMN and longevity claims. Related: experimental longevity compounds.