What is nicotinamide riboside (NR)? A plain guide

Nicotinamide riboside (NR) is a form of vitamin B3 that the body converts into NAD+, a coenzyme every cell needs to make energy and carry out DNA repair. It's one of three B3 vitamers sold as supplements — alongside niacin (nicotinic acid) and niacinamide (nicotinamide) — and it reaches NAD+ through a different pathway than either of the other two.

Where it fits among the B vitamins

Niacin, niacinamide, and nicotinamide riboside are all forms of "vitamin B3": different chemical starting points the body can turn into NAD+, each processed through its own gene-encoded pathway, and each behaving differently at supplement doses. Niacin can lower blood lipids but causes flushing — a warm, reddening skin reaction — at doses above roughly 50 mg. Niacinamide doesn't cause flushing or lower lipids, but has been reported to raise blood homocysteine, a marker linked to vascular disease, more than niacin does at a comparable dose. Nicotinamide riboside is the newest of the three to be studied in people: the first published human trial of its safety and pharmacokinetics ran in 2016 (PMID 27721479, PMID 31278280).

Is nicotinamide riboside the same as niacin?

No. Both eventually become NAD+, but they don't behave the same way in the body along the way. Niacin's flushing reaction happens because nicotinic acid binds a receptor called GPR109A on skin cells, triggering the release of compounds that widen blood vessels; nicotinamide riboside isn't expected to bind that receptor the same way (PMID 29599478). In an 8-week, placebo-controlled trial of 140 adults given up to 1,000 mg of NR a day, there were no reports of flushing at any dose (PMID 31278280). That's a result from one trial, not proof flushing is impossible for everyone, but it's the clearest human evidence for the distinction.

How it's thought to work

NR is absorbed and converted toward NAD+ through what researchers call the salvage pathway. The first published human study measured this directly: a single oral dose in one person raised blood NAD+ as much as 2.7-fold, and in a follow-up trial of 12 healthy adults, single doses of 100, 300 and 1,000 mg each produced a dose-dependent rise in blood NAD+ (PMID 27721479). That's a measured change in a blood biomarker — not the same thing as a measured change in how someone feels or performs. See nicotinamide riboside (NR) benefits: what the research does and doesn't show for what's actually been tested beyond that biomarker.

Nicotinamide riboside vs. NMN

Nicotinamide mononucleotide (NMN) is a different molecule, one step further along the same pathway toward NAD+. Both are sold as NAD+-related supplements, and both have raised NAD+ levels in their own separately run human trials. We didn't find a human trial that tested NR and NMN head-to-head in the same people, so there's no direct comparison to report here — just two separately studied molecules aimed at the same coenzyme.

Where it comes from

Nicotinamide riboside occurs naturally in small amounts in food, including in milk, and the body also produces some as part of normal NAD+ turnover (PMID 31278280). Supplement forms are typically sold as a stabilized salt — commonly nicotinamide riboside chloride — since the free molecule is less stable for shelf storage.

Questions people ask

What foods contain nicotinamide riboside?

It's present in small amounts in milk; detailed food-composition data on other sources is limited (PMID 31278280). Nobody reaches the amounts used in the clinical trials above through diet alone — that's the reason it's sold as a concentrated supplement.

What is nicotinamide riboside used for?

People take it hoping to raise their NAD+ levels, which do measurably rise in trials. Whether that translates into a felt or measured benefit is a separate, much less settled question — see nicotinamide riboside (NR) benefits: what the research does and doesn't show.

How do you take nicotinamide riboside?

As a capsule, typically once or twice a day depending on the product. See how much nicotinamide riboside (NR) should you take a day? and when is the best time to take nicotinamide riboside (NR)? for what the trials actually used.

Which brand of nicotinamide riboside should I choose?

This page doesn't recommend one. See how to choose a good nicotinamide riboside (NR) for what to check on any label — the form, the dose against what's been tested, and testing — regardless of brand.

Is nicotinamide riboside proven to work?

It's reliably shown to raise blood NAD+ levels across human trials. A 2023 review that assessed the 25 published human studies on NR available at the time concluded that, collectively, oral NR supplementation has shown few clinically relevant effects beyond that biomarker change, and cautioned that some published claims about it have exaggerated what the underlying data actually show (PMID 37478182).

Is nicotinamide riboside the same as NAD?

No — NR is a precursor the body converts into NAD+, not NAD+ itself. Taking NR is a way of supplying raw material for NAD+ production, not a way of ingesting the coenzyme directly.

Related reading: nicotinamide riboside (NR) benefits: what the research does and doesn't show, how much nicotinamide riboside (NR) should you take a day?, and how to choose a good nicotinamide riboside (NR).