Daily cellular protocol
NAD+
500mg of NAD+ supported by Quercetin and Resveratrol, dosed once daily for cellular energy and metabolic health.
View NAD+Longevity, carefully
NAD+ and Aging: The Decline Is Real, the Promises Are Not
This is the claim the entire category is built on. Half of it is well documented. The other half has never been demonstrated in a person.
This guide is part of our NAD+ supplement guides track. For continuity, read our NAD+ longevity formula and NAD+ for men.
The short answer
NAD+ declines with age in human tissue — Massudi and colleagues measured it directly in skin from donors aged 0 to 77 and found a strong negative correlation. Oral precursors reliably restore circulating NAD+, with Martens and colleagues showing roughly a 60% rise at 1000mg/day of nicotinamide riboside. What has never been demonstrated is that raising NAD+ extends human lifespan or reverses ageing. The first two claims are evidence. The third is the marketing.
Decision brief
What matters before you buy
The age-related NAD+ decline is measured in human tissue, not just modelled.
Oral precursors reliably restore circulating NAD+ in randomized trials.
No human trial has demonstrated that this extends lifespan or reverses ageing.
Trial outcome measures — strength, metabolism, body composition — have largely come back null.
Muscle Velocity standard
A real mechanism, described honestly
500mg of NAD+ with Quercetin and Resveratrol. We will tell you the decline is measured and the reversal is not — then let you decide.
Educational content only. Supplements are not a substitute for medical care. Speak with a qualified healthcare professional when a condition, medication, or persistent symptom is involved.
The part that is genuinely established
Massudi and colleagues sampled non-sun-exposed skin from 49 donors ranging from newborn to 77 years old and found a strong negative correlation between NAD+ and age: r = −0.706 in males and r = −0.537 in females. They described it as the first demonstration that NAD+ declines with age in human tissue.
They connected it to PARP activity. PARPs consume NAD+ while repairing DNA damage, and oxidative damage accumulates over a lifetime, so more of the available NAD+ is spent on repair as you get older.
That is a coherent, measured account of why the molecule becomes scarcer. It is a genuinely good reason to find the category interesting.
The part that is not
Restoring the biomarker is achievable. The Martens crossover — thirty adults aged 55–79, double-blind, placebo-controlled — raised NAD+ in peripheral blood mononuclear cells roughly 60% at 1000mg/day of nicotinamide riboside. That trial also found blood pressure and arterial stiffness improvements that did not survive statistical correction.
What follows from restoring it is where the field goes quiet. A 2024 meta-analysis of eight NMN trials in 342 adults found no significant change in glucose, insulin, HbA1c, lipids, BMI, or blood pressure. A 2024 review of ten performance trials found strength and aerobic improvements described as nonsignificant.
No human trial has tested lifespan, because a human lifespan trial is not a practical study design. Any product implying otherwise is selling a rodent result with a human photograph attached.
- Measured in humans: NAD+ declines with age in tissue
- Measured in humans: oral precursors restore circulating NAD+
- Not demonstrated: improved lifespan, reversed ageing, or restored youthful function
- Largely null: the metabolic and strength outcomes trials actually measured
How to hold both halves at once
The reasonable position is that NAD+ decline is a real feature of ageing biology, that supplementation demonstrably addresses the biomarker, and that whether this matters for how you age is unresolved. You can find that worth a modest monthly spend without believing anything unproven.
What you should not do is let it displace the interventions that do have ageing evidence: resistance training, sleep, protein intake, cardiovascular fitness, and not smoking. Those are not glamorous and they are not in a bottle, and they outrank everything in this category.
Gindri and colleagues reviewed NAD and its precursors across ten studies and 489 participants in varied clinical populations and found them well tolerated. Well tolerated is a reason it is reasonable to try. It is not a reason to expect a transformation.
Buying checklist
How to choose without getting sold
No lifespan or reversal claims
No human trial has tested either. A product making the claim is telling you what it thinks you will believe.
Rodent data labelled as rodent data
Much of the longevity story in this category comes from animal work. Check which species a cited result came from.
A dose inside the studied range
150–2000mg/day covers the published trials depending on precursor and outcome measured.
Realistic framing of what it addresses
Restoring a declining coenzyme is defensible. Restoring youth is not a claim anyone can currently support.
Fit check
Who this path is—and is not—for
Good fit
- Adults over 40 who want the ageing science stated accurately before buying
- Readers who can hold a real mechanism and null outcomes in mind at once
- Anyone who has already got training, sleep, and nutrition in order
Poor fit
- Anyone expecting a supplement to slow or reverse ageing
- Readers looking for a substitute for exercise and sleep
- People wanting certainty this field does not currently offer
Common questions
The questions worth answering
Does NAD+ really decline with age?
Yes, and it has been measured directly in human tissue. Massudi and colleagues sampled skin from 49 donors aged 0 to 77 and found a strong negative correlation with age, r = −0.706 in males and r = −0.537 in females.
Does taking NAD+ slow aging?
No human trial has demonstrated that. Supplementation reliably restores circulating NAD+, but trials measuring downstream outcomes — metabolic markers, strength, body composition — have largely returned null results. Lifespan has never been tested in humans.
At what age should I start taking NAD+?
No trial has established an optimal starting age. The randomized studies mostly enrolled middle-aged and older adults, with the Martens crossover recruiting people aged 55 to 79. That tells you where the evidence was gathered, not when you should begin.
Is NAD+ safe for long-term use?
Gindri and colleagues reviewed ten studies covering 489 participants across varied clinical conditions and found NAD and its precursors well tolerated, and a 2024 NMN review reported no serious adverse effects. Those are short trials, so they support short-term safety rather than open-ended reassurance.
Evidence desk
Read the sources, not just the summary
Massudi et al., PLOS ONE (2012) — age-associated NAD+ decline in human tissueMeasured NAD+ in non-sun-exposed skin from 49 donors aged 0–77. Reported a strong negative correlation with age in males (r = −0.706) and females (r = −0.537).Martens et al., Nature Communications (2018) — chronic NR supplementation in middle-aged and older adultsRandomized, double-blind, placebo-controlled crossover trial. 1000mg/day nicotinamide riboside raised NAD+ in peripheral blood mononuclear cells by roughly 60% versus placebo.Gindri et al., American Journal of Physiology-Endocrinology and Metabolism (2023) — safety and effectiveness of NAD across clinical conditionsSystematic review of ten studies and 489 participants spanning chronic fatigue, older adults, Parkinson's disease, overweight, prediabetes, and Alzheimer's disease.
Continue the NAD+ guide
By goal
What the trials support for a specific outcome — and what they do not.
Metabolism, measurednad for weight lossSkin, without the before-and-afternad for skinWhere it fits for menbest nad supplement for men
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