Nicotinamide Riboside and Muscle Health: What NAD+ Research Shows

Nicotinamide riboside (NR) is a precursor used in the body’s NAD-related metabolism. NAD+ is involved in energy production, redox reactions, and cellular maintenance, which gives NR a plausible story for ageing and muscle health. Plausibility is not the same as a proven training outcome.

Biomarkers versus muscle outcomes

Human NR studies can show changes in NAD-related metabolites or gene-expression signatures. Those are legitimate biological outcomes, but they do not automatically mean more strength, muscle mass, or better training recovery.

In a placebo-controlled crossover study of 12 older men, NR changed the skeletal-muscle NAD+ metabolome during the intervention, but the study did not establish a meaningful improvement in mitochondrial bioenergetics or athletic performance. Read the study.

A 2025 systematic review and meta-analysis of NAD precursors and skeletal-muscle outcomes in older adults concluded that current evidence did not support NR or NMN for preserving muscle mass and function. It noted that future work still needs to clarify dose, baseline NAD status, and combined interventions. Read the review.

The broader exercise review is similarly cautious: NAD+ therapeutics have not been shown to improve athletic performance or skeletal-muscle metabolism reliably in healthy humans. See the review.

What NR is not

NR is not a proven replacement for creatine, protein, progressive resistance training, or treatment for sarcopenia. It is not appropriate to infer from a higher NAD+ marker that a person will preserve muscle during a diet, recover faster, or build more tissue.

Claims about a universal age-related percentage decline, a fixed NR dose, or a guaranteed mitochondrial benefit should be treated as marketing unless they are tied to a specific human study and outcome.

Who should be cautious

Most NR trials use older or clinically selected populations rather than young resistance-trained lifters. A product may be studied at one dose and formulation while a commercial product uses another. Long-term safety and clinically meaningful benefits remain separate questions.

Do not use NR to self-treat fatigue, weakness, metabolic disease, or sarcopenia. Persistent symptoms deserve medical assessment, and supplement use should be reviewed with a clinician or pharmacist when medication or chronic disease is involved.

If you still want to experiment

Define the outcome before buying the product. If your goal is strength, record repeatable lifts and effort. If your goal is fatigue or health, use clinically meaningful measures rather than a home “NAD test.” Keep training, diet, sleep, and caffeine stable enough to interpret the result, and do not assume a few weeks of a biomarker change predicts a long-term muscle effect.

Bottom line

NR is biologically interesting and can alter NAD-related biomarkers in some human studies. Current evidence does not establish better muscle mass, strength, or performance for healthy lifters, and a 2025 synthesis was cautious even in older adults. Treat NR as an unproven supplement, not an anti-ageing or hypertrophy shortcut.

Related reading

• Urolithin A and Muscle Health: What the Human Evidence Shows
• PQQ and Mitochondrial Muscle Health: Evidence Limits
• Creatine Monohydrate: The Science Behind the Most Researched Supplement

Applying this article

Do not change medication or use NR to self-treat a symptom. If you test it with appropriate professional guidance, define one outcome, use a consistent product, and track training, symptoms, and tolerance rather than relying on a biomarker alone.

Limits of the evidence

NR studies differ in age, health, dose, product, duration, and outcome. NAD-related biomarkers, molecular signatures, muscle mass, and performance are not interchangeable endpoints.

Sources

• NR and the aged human skeletal-muscle NAD+ metabolome. Small placebo-controlled crossover study; biomarker and transcriptomic outcomes.
• Nicotinamide mononucleotide and riboside for skeletal muscle mass and function. 2025 systematic review and meta-analysis.
• NAD+ therapeutics and skeletal-muscle adaptation to exercise. Review of human and preclinical evidence.