Article: Differential Effects of NR, NMN, and Nicotinamide on NAD+ and Microbial Metabolism: Clinical Findings

Jan 15, 2026 Clinical Digestive/Gut Health Pharmacokinetic/Safety

Differential Effects of NR, NMN, and Nicotinamide on NAD+ and Microbial Metabolism: Clinical Findings

Objectives

To compare the effects of NR, NMN, and NAM on NAD+ levels and investigate how gut microbes metabolize each precursor.

Journal

Nature Metabolism

Key Outcomes

NR and NMN produced similar, approximately twofold increases in blood NAD+ after 14 days.
NAM produced a short-lived increase but did not significantly raise sustained blood NAD+ levels.
In ex vivo fecal analyses, fecal microbes converted NR, NMN, and NAM into niacin, suggesting a role for microbial metabolism.

Duration

14 days

Dose

1000 mg*

*Participants received 1,000 mg of NR, 1,000 mg of NMN, or 500 mg of NAM.

Study Design

Ex Vivo

A fermentation assay was conducted by exposing fecal-derived microbiota from 6 healthy adults to NAD+ precursors

In Vivo

Randomized, open-label, placebo-controlled, parallel study in 67 healthy adults

See Published Study

Clinical

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