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Pooled review (meta-analysis)

Pooled review of 15 NMN trials found no extra side effects or liver changes

Yang and colleagues · Nutrients · 2026

Original title: Safety and Metabolism-Related Outcomes of Oral Nicotinamide Mononucleotide Supplementation in Adults: A Systematic Review and Meta-Analysis.

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

No difference

NMN did not raise side effects or liver enzymes. Body weight, BMI, fasting glucose, HbA1c, blood fats and systolic blood pressure did not change. Diastolic blood pressure fell slightly.

The study at a glance

Type of study
Pooled review (meta-analysis)
Who or what was studied
15 studies · Adults in 15 randomized trials of NMN
What was tested
Oral NMN 250-2000 mg a day for 14 days to 24 weeks, vs placebo or control
What it measured
Side effects and safety
Daily amount
2000 mg a day
How long
24 weeks
Trial registration
CRD420261382497
Who has a stake
No stake declared
No conflicts of interest declared.
Journal
Nutrients, 2026
Source
PubMed record 42514320. This page is based on the abstract only.

How much this study counts

  • ✓Pools the results of 15 studies.
  • •A pooled review is only as strong as the studies it pools.
  • •Measured side effects and safety.
  • ✓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 pooled review (meta-analysis), 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”: Across fifteen trials lasting 14 days to 24 weeks, NMN at 250-2000 mg/day did not raise side effects or liver enzymes. Longer trials are still needed.
  • Part of the finding “Blood sugar and blood fats: little change”.
  • Summed up in “What reviews found”: Pooled fifteen NMN trials lasting 14 days to 24 weeks. NMN did not raise side effects or liver enzymes. Weight, blood sugar and blood fats did not change; diastolic blood pressure fell slightly.
  • Open item for a person: Pooled reviews Chen 2024, Zhang 2025, Wang 2025, Yang 2026 and Gao 2026 likely share many trials; their people counts should not be added.

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 reviewer corrected 2 fields after reading the abstract. 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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