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Systematic review

Review of 113 studies of NAD+ boosters: higher blood markers, but health benefit unclear

Gallagher and colleagues · Ageing research reviews · 2026

Original title: NAD⁺ supplementation for anti-aging and wellness: A PRISMA-guided systematic review of preclinical and clinical evidence.

Under review. A person has not yet checked this summary against the paper. It is written from the PubMed abstract. Until a person checks it, search engines are asked not to list this page.

What the study found

Mixed

In people, NR and NMN raised NAD-related blood markers and were generally well tolerated. Effects on function and other health measures were often null or varied by endpoint. The authors call clinical benefit for anti-aging inconclusive.

The study at a glance

Type of study
Systematic review
Who or what was studied
113 studies · People and rodents in 113 studies of NAD+ boosters such as NR and NMN
What was tested
NR, NMN or NAD+ given by mouth or by injection, compared with control
What it measured
Several kinds of outcomes
Who has a stake
No stake declared
One author owns a clinic services company that does not sell NAD+ products. No other competing interests.
Journal
Ageing research reviews, 2026
Source
PubMed record 41655607. This page is based on the abstract only.

How much this study counts

  • •Sums up 113 studies found with a set search method, without pooling the numbers.
  • •Measured several kinds of outcomes.
  • ✓No competing interests declared.
  • •Summarized from the PubMed abstract only. The full paper may hold details the abstract leaves out.

✓ Strength– Limit• Note

These points come from fixed rules about the type of study, its size and length, what it measured, and who has a stake. Every study on Digestery gets the same rules.

Where this study sits

This paper is not on the ladder. It is a systematic review, and reviews and opinion pieces discuss studies that are already counted on the steps below.

↑ Stronger evidence

  1. Trials in people: aging and age-related decline

    0

    Not done yet. This is the step that would answer the question.

  2. Trials in people: other measures

    9

    3 benefit, 2 mixed, 4 no difference

  3. Trials in people: lab tests or safety

    7

    4 benefit, 1 mixed, 2 no difference

  4. Population studies

    0

    None among the papers we read.

  5. Blood levels and genes

    0

    None among the papers we read.

  6. Animals

    6

    5 benefit, 1 mixed

↓ Weaker evidence

  • Points to benefit
  • Mixed
  • No difference
  • No direction
  • Points to harm

How it fits with the other research

The short answer to “Does NMN slow aging?”

Not shown in people so far.

Confidence: very low. Based on 29 on-topic papers.

Read the full answer
  • Quoted in “What we found”: In people, NMN and NR consistently raised NAD+ and related compounds in blood, a review of 33 human studies found. Raised NAD+ is a marker, not slower aging.
  • Part of the finding “Boosters raise NAD+, but that is a marker”.
  • Summed up in “What reviews found”: Reviewed 113 studies: 33 in people and 80 in rodents. In people, NR and NMN raised NAD+ markers, but effects on function and health were mixed and often absent. It calls anti-aging benefit inconclusive.
  • Open item for a person: Gallagher 2026 author owns a firm serving an aesthetics clinic that offers no NAD+; stake kept as none.

Other reviews on this question

See all 29 studies on this question

How this page was made

Label

First read of the abstract
Claude Sonnet
Independent second read
Claude Haiku
Differences settled
The two reads differed. The reviewer checked the abstract and kept the first read. Claude Opus 5.5.
Headline
Claude Sonnet, from the checked study record. A script checked its numbers and wording.
Numbers
Checked against the abstract by a script
“How much this study counts”
Fixed rules, the same for every study
Source check by a person
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