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Pooled review (meta-analysis)

Pooled review of 12 NMN trials found no clear blood sugar or fat change

Zhang and colleagues · Critical reviews in food science and nutrition · 2025

Original title: Efficacy of oral nicotinamide mononucleotide supplementation on glucose and lipid metabolism for adults: a systematic review with meta-analysis on randomized controlled trials.

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What the study found

No difference

NMN raised blood NAD levels. Most clinically relevant outcomes did not differ from control. Seven studies had some concerns and five had high risk of bias. Authors suggest benefits may be exaggerated.

The study at a glance

Type of study
Pooled review (meta-analysis)
Who or what was studied
12 studies, 513 people · Adults in 12 trials of NMN
What was tested
Oral NMN vs control, looking at blood sugar and blood fats
What it measured
Lab tests or markers
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
Critical reviews in food science and nutrition, 2025
Source
PubMed record 39116016. This page is based on the abstract only.

How much this study counts

  • ✓Pools the results of 12 studies with 513 people.
  • •A pooled review is only as strong as the studies it pools.
  • –Measured lab tests or markers, which stand in for aging and age-related decline. A better marker does not always mean better health.
  • •The PubMed record has no conflict-of-interest statement.
  • •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
  • Part of the finding “Blood sugar and blood fats: little change”.
  • Summed up in “What reviews found”: Pooled 12 studies with 513 people. NMN raised blood NAD, but most health measures did not differ from control. Every trial had bias concerns, and the authors warn benefits may be exaggerated.
  • 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 two reads agreed on every checked field. 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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