Elhassan · Cell reports 2019 · randomized double-blind placebo-controlled crossover trial · n=12

Nicotinamide Riboside Augments the Aged Human Skeletal Muscle NAD + Metabolome and Induces Transcriptomic and Anti-inflammatory Signatures.

Cited 450 times in the scientific literature.

Level 2 - randomized trial

Randomized double-blind placebo-controlled crossover trial in humans

PubMed 31412242 · doi:10.1016/j.celrep.2019.07.043 · record verified 2026-08-29

What was done

In a randomized, double-blind, placebo-controlled crossover trial, 12 aged men received oral nicotinamide riboside (NR) at 1 g per day or placebo for 21 days. The investigators evaluated skeletal muscle targeted metabolomics, muscle transcriptomics via RNA sequencing, muscle mitochondrial bioenergetics, and circulating inflammatory cytokines.

What was found

The abstract reports directional findings without numerical values or effect sizes. Oral NR supplementation elevated the skeletal muscle NAD+ metabolome, evidenced by increases in nicotinic acid adenine dinucleotide and nicotinamide clearance products. Muscle RNA sequencing showed downregulation of energy metabolism and mitochondrial pathways without altering mitochondrial bioenergetics. NR supplementation also depressed circulating inflammatory cytokine levels.

Why it matters

This trial demonstrates that oral NR is bioavailable to human aged skeletal muscle and induces systemic anti-inflammatory signatures. However, short-term NAD+ augmentation did not enhance muscle mitochondrial bioenergetics.

Limits

The sample size is very small (n = 12) and exclusively enrolled older men, limiting generalizability to women and broader populations. The intervention was brief (21 days), and the abstract lacks quantitative values, statistical confidence intervals, and clinical or functional muscle performance outcomes.

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