Chronic nicotinamide mononucleotide supplementation elevates NAD+ in older men: a randomized, placebo-controlled trial

Published 2021

Study Design

Population
30 healthy older men aged ≥ 65 years
Design
Randomized, double-blind, placebo-controlled, parallel-group trial
Dosage
250 mg/day NMN
Duration
12 weeks

Citation

npj Aging and Mechanisms of Disease (2021).

Authors: Igarashi, M., Mori, T., Yamaguchi, S., Ito, T., Yoshino, J.

Affiliation: University of Toyama School of Medicine, Toyama, Japan

Find the original study here →DOI Reference

Plain takeaway

250 mg/day NMN for 12 weeks raised NAD+ and modestly improved muscle performance in older men without adverse effects.

Study context

Hypothesis: Daily supplementation with 250 mg NMN increases NAD+ levels and enhances muscle performance in older men compared to placebo.

Objective: To evaluate the safety, NAD+ elevation, and functional effects of 250 mg/day NMN supplementation for 12 weeks in men aged ≥ 65 years.

Abstract

In a 12-week placebo-controlled RCT in older men, daily 250 mg NMN raised NAD+ and improved some markers of muscle function without safety issues, supporting NMN’s role in human NAD+ metabolism.

Methods & Controls

Participants received 250 mg NMN or placebo for 12 weeks. Whole-blood NAD+ levels were quantified, and gait speed, grip strength, and muscle performance were assessed at baseline and end-of-study.

Controls: Identical placebo capsules administered once daily; both participants and investigators blinded.

Key outcomes

  • Whole-blood NAD+ increased significantly in NMN group versus placebo.
  • Gait speed and grip strength showed improvements in NMN group, though not all reached statistical significance.
  • No serious safety concerns or adverse effects observed.

Summary & Interpretation

This RCT strengthens evidence that NMN can elevate NAD+ safely in aging humans, showing functional gains consistent with preclinical findings. Further large-scale and long-term trials are warranted.

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