NAD+ Supplements: Resveratrol, NMN, NR — Are They Worth It?

What Is NAD+ and Why Does It Matter?

Nicotinamide adenine dinucleotide (NAD+) is a coenzyme found in every cell. It's involved in: - Energy metabolism (electron transfer in mitochondria) - DNA repair (PARP enzymes require NAD+) - Sirtuin activation (sirtuins are NAD+-dependent deacetylases involved in cellular stress resistance, inflammation, and lifespan regulation) - Circadian rhythm regulation

The ageing connection: NAD+ levels decline with age — some estimates suggest levels fall 50% between 40 and 60 years. Lower NAD+ is associated with mitochondrial dysfunction, increased inflammation, and impaired DNA repair — all hallmarks of ageing.

In animal models (mice, C. elegans), raising NAD+ extends lifespan and improves metabolic health. These results have fuelled enormous commercial interest in NAD+-boosting supplements.

The Supplement Landscape

NMN (Nicotinamide Mononucleotide)

A direct precursor to NAD+. Converted to NAD+ via the salvage pathway. Naturally present in small amounts in vegetables (edamame, broccoli, avocado).

Human evidence: - A 2020 pilot study (Nature Metabolism, n=25) found 250mg NMN daily for 10 weeks improved insulin sensitivity and muscle health in postmenopausal women with prediabetes. - A 2022 RCT found 300mg/day improved NAD+ levels in blood but no significant metabolic differences vs placebo in healthy adults. - Studies are generally small and short-term. Hard endpoint data (disease outcomes, lifespan) is absent.

Cost: £30–80/month. Premium for early-stage evidence.

NR (Nicotinamide Riboside)

Another NAD+ precursor, converted via the salvage pathway. Better-studied than NMN currently.

Human evidence: - Multiple RCTs confirm NR supplementation raises blood NAD+ levels dose-dependently (250–1,000mg/day) - A 2018 RCT in healthy adults (n=24) confirmed significant NAD+ elevation with 250mg/day NR - However: most studies don't show downstream metabolic improvements in healthy adults. The rise in NAD+ doesn't automatically translate to measurable benefits.

Better evidence in specific contexts: - Heart failure: A small 2020 RCT showed NR improved mitochondrial function in heart failure patients - Ataxia-telangiectasia (rare neurological disease): 2021 trial showed significant improvements

Resveratrol

A polyphenol found in red grape skins, blueberries, and Japanese knotweed. Acts as a SIRT1 activator — and SIRT1 requires NAD+ as a cofactor. Marketing often frames it as a "NAD+ amplifier."

The research story: - Initial excitement from Sinclair/Guarente lab mouse studies (2003–2006) - GSK acquired Sirtris Pharmaceuticals for $720M in 2008 to develop resveratrol drugs - GSK discontinued Sirtris pipeline in 2013 after clinical trial failures - Independent replication of the mouse studies by Pfizer and Novartis failed

Human evidence: - Mostly negative for hard endpoints in healthy adults - Some positive signals for specific populations: type 2 diabetes (improved insulin sensitivity in some trials), Alzheimer's progression (one notable 2015 trial)

Bioavailability problem: Resveratrol is rapidly metabolised and has extremely poor bioavailability. Most supplements reach negligible plasma concentrations.

Verdict: The resveratrol story is one of science's more spectacular commercial overpromises.

Pterostilbene

A resveratrol analogue found in blueberries with better bioavailability. Early research is interesting, but human evidence is even thinner than resveratrol.

Should You Supplement NAD+ Precursors?

For healthy people under 40: Evidence is insufficient to justify the cost. Sleep, exercise, and limiting alcohol raise NAD+ levels more reliably than any current supplement.

For people over 50 interested in longevity: The biological rationale is sound and the safety profile of NR and NMN appears good. Consider NR (better studied) at 300–500mg daily. Don't expect proven disease prevention — it's investment in an emerging field.

For people with specific conditions (heart failure, metabolic syndrome, diabetes): More compelling evidence — discuss with a specialist.

The Lifestyle Approach (More Evidence, Zero Cost)

Exercise: Aerobic exercise and resistance training both raise NAD+ levels via activation of the AMPK/SIRT1 pathway.

Intermittent fasting / caloric restriction: Activates sirtuins and raises NAD+.

Limiting alcohol: Alcohol consumption depletes NAD+ (conversion to NADH during ethanol metabolism).

Cold exposure: Activates AMPK, which increases NAD+ levels.

The field is moving fast. Evidence adequate to make strong recommendations isn't yet there — but the mechanistic rationale is compelling. Watch this space.