Chronic nicotinamide mononucleotide supplementation elevates blood nicotinamide adenine dinucleotide levels and alters muscle function in healthy older men

This placebo-controlled trial examined 250 mg/day NMN in healthy older men. NMN increased whole-blood NAD+ and related metabolites and was reported as well tolerated.

The publication reported nominal improvements in gait speed and left-hand grip performance, while body-composition outcomes did not significantly improve. The authors themselves noted that the muscle-function findings require validation in larger studies.

Interpretation is complicated by a test-food allocation error after six weeks that caused participants to receive the opposite intervention during part of the study, reducing the cleanly interpretable 12-week efficacy sample.

• Whole-blood NAD+ and multiple NAD-related metabolites increased with NMN supplementation.
• No significant deleterious safety effect was reported.
• Gait speed and left-grip performance showed nominally significant improvements that the authors described as needing validation.
• Body composition did not significantly change.
• A test-food allocation error materially limits interpretation of longer-duration efficacy comparisons.

• The study enrolled only older men, limiting generalizability by sex and age.
• A test-food allocation error after week 6 compromised the intended 12-week treatment assignment.
• The muscle-function findings were nominal and require replication in larger trials.
• Body-composition outcomes were null.
• The study was funded by the NMN supplier, and three authors were company employees.