Healthspan.

NAD+ boosters: what they do and don't do

Evidence grade: Moderate. Human trials show NAD+ precursors raise NAD+ levels. Human data on health outcomes are small, short and mixed. Effects on aging are animal data only. See how we grade.

What an "NAD+ booster" is

NAD+ is a molecule every cell uses in energy metabolism. It also acts as a signal that controls many processes, rising and falling with food intake, exercise and time of day [1]. "NAD+ booster" is a marketing term for anything meant to raise it. The best-studied are precursors, the building blocks the body turns into NAD+.

The two you will see most are NR (nicotinamide riboside) and NMN (nicotinamide mononucleotide). NR is a member of the vitamin B3 family [2]. Older B3 forms, nicotinic acid and nicotinamide, are also NAD+ precursors. In mice, oral NR raised liver NAD+ with different and stronger pharmacokinetics than those two [3].

Why people take them

The idea comes from animal research. A 2018 review describes NAD+ declining with age, and restoring it in old or diseased animals promoting health and extending lifespan [1]. The hope is that the same holds in people. That has not been shown.

What human trials show: NAD+ goes up

This part is solid. NR raised the blood NAD+ metabolome in a dose-dependent way in the first human pharmacokinetic trial [3]. In an 8-week trial, 100, 300 and 1,000 mg of NR per day raised whole-blood NAD+ by 22%, 51% and 142% within two weeks [4]. NR also raised NAD+ metabolites in the muscle of 12 older men [5]. NMN raised blood NAD+ in healthy older men at 250 mg per day [6] and in middle-aged adults at 300 to 900 mg per day [7].

A higher NAD+ reading is a change in a measurement. It is not the same as a health benefit.

What human trials show: health effects are mixed

NMN increased muscle insulin sensitivity in a 10-week trial in postmenopausal women with prediabetes who were overweight or obese [8]. NR, at 2,000 mg per day for 12 weeks, did not improve insulin sensitivity in obese, insulin-resistant men [2]. NR lowered some inflammatory markers in older men without changing muscle mitochondrial function [5]. NMN showed nominal improvements in gait speed and grip that the authors said need larger studies [6].

These are small trials in specific groups, lasting weeks. Mixed results like this are why we grade the area Moderate, not Strong.

Safety and who should be careful

In the trials above, the precursors were well tolerated. The 8-week NR trial reported no flushing and no significant difference in adverse events versus placebo [4]. NR at 2,000 mg per day for 12 weeks caused no serious adverse events [2]. NMN up to 900 mg per day for 60 days showed no safety issues [7].

None of these trials lasted longer than 12 weeks. If you take prescription medication, have a chronic illness, or are pregnant or breastfeeding, talk to a doctor first.

How to read the label

  • Check the ingredient and the amount. Trials tested specific doses of specific molecules. A blend of many things at small amounts is not what was studied.
  • Treat "anti-aging" claims as unproven. We know of no human trial showing an NAD+ booster slows aging.
  • Know the legal status is not proof. In the US, the FDA concluded in September 2025 that NMN is not excluded from the dietary supplement definition [9]. That decides whether it can be sold, not whether it works.
  • Look at who funded the evidence. The first NR pharmacokinetic trial was sponsored by the NR supplier [3].

Our NAD protocol covers how we place these products. It sits after the foundations: sleep, movement and diet come first.

If you decide to buy, these are products we can link to:

These are affiliate links. If you buy through them, we earn a commission, and you don't pay more.

Frequently asked questions

What is an NAD+ booster?

It is a supplement meant to raise NAD+, a molecule cells use for energy metabolism and signalling. The best-studied ones are the precursors NR and NMN, which the body converts into NAD+.

Do NAD+ boosters work?

They raise NAD+ levels in human blood, which is well shown. Whether that improves health is less clear: small trials show mixed results, and we know of no human trial showing they slow aging.

Does NAD+ decline with age?

A 2018 review describes NAD+ declining with age, based largely on animal research. Restoring NAD+ improved health and lifespan in animals, but that has not been shown in people.

Are NAD+ boosters safe?

In trials lasting up to 12 weeks, NR and NMN were well tolerated without serious safety signals. Long-term safety is not known. Talk to a doctor if you take medication, have a condition, or are pregnant.

Which NAD+ booster is best?

No trial we know of has compared NR and NMN head to head on a health outcome. Both raise NAD+. Choose a product that states the exact molecule and amount, and keep expectations modest.

Sources

  1. Therapeutic Potential of NAD-Boosting Molecules: The In Vivo Evidence. Cell Metabolism, 2018. Review. https://pubmed.ncbi.nlm.nih.gov/29514064/
  2. A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects. The American Journal of Clinical Nutrition, 2018. https://pubmed.ncbi.nlm.nih.gov/29992272/
  3. Nicotinamide riboside is uniquely and orally bioavailable in mice and humans. Nature Communications, 2016. https://pubmed.ncbi.nlm.nih.gov/27721479/
  4. Safety and Metabolism of Long-term Administration of NIAGEN (Nicotinamide Riboside Chloride) in a Randomized, Double-Blind, Placebo-controlled Clinical Trial of Healthy Overweight Adults. Scientific Reports, 2019. https://pubmed.ncbi.nlm.nih.gov/31278280/
  5. Nicotinamide Riboside Augments the Aged Human Skeletal Muscle NAD+ Metabolome and Induces Transcriptomic and Anti-inflammatory Signatures. Cell Reports, 2019. https://pubmed.ncbi.nlm.nih.gov/31412242/
  6. Chronic nicotinamide mononucleotide supplementation elevates blood nicotinamide adenine dinucleotide levels and alters muscle function in healthy older men. npj Aging, 2022. https://pubmed.ncbi.nlm.nih.gov/35927255/
  7. The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial. GeroScience, 2023. https://pubmed.ncbi.nlm.nih.gov/36482258/
  8. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science, 2021. https://pubmed.ncbi.nlm.nih.gov/33888596/
  9. FDA response to citizen petition on the regulatory status of beta-nicotinamide mononucleotide (NMN), Docket FDA-2023-P-0872 (letter to Natural Products Association and Alliance for Natural Health USA). U.S. Food and Drug Administration (copy hosted by the American Herbal Products Association), 2025. Letter dated September 29, 2025 (the PDF header prints the year as 2029, an apparent typo). https://www.ahpa.org/Files/PDFs/AHPAUpdate/25_0930%20NPA%20NMN%20FDA%20CP%20Response.pdf