Supplement analysis backed by scientific evidence · PT

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Limited evidenceLongevity & antioxidants

Nicotinamide Riboside

The best-studied NAD+ precursor, with clean safety data and reliable NAD+ elevation — and a consistent record of failing to improve any functional outcome in well-controlled human trials. Excellent biomarker, no demonstrated benefit.

What the science says

  • Raising NAD+ levels Strong evidence

    This is settled. In a randomized crossover trial in healthy middle-aged and older adults (Martens et al., Nature Communications 2018), 1,000 mg/day NR for 6 weeks roughly doubled whole-blood NAD+, and multiple independent trials have reproduced dose-dependent NAD+ elevation at 250-2,000 mg/day. NR is well absorbed and well tolerated.

  • Insulin sensitivity and metabolic health Limited evidence

    The Dollerup trial (AJCN 2018) gave 2,000 mg/day NR to obese, insulin-resistant men for 12 weeks and found no effect on insulin sensitivity by hyperinsulinemic-euglycemic clamp, no change in hepatic or muscle lipid content, and no change in resting energy expenditure — despite good tolerability. Subsequent metabolic trials have largely echoed this null result.

  • Blood pressure and arterial stiffness Limited evidence

    The Martens 2018 trial reported an exploratory 9 mmHg reduction in systolic BP in the subgroup with elevated baseline BP, but this was a secondary analysis in a small sample and the primary blood-pressure outcome was not significant. It should be treated as hypothesis-generating, not as an established effect.

  • Muscle mass, strength and physical function Limited evidence

    A 2025 meta-analysis of NAD+ precursor trials found no significant effect on skeletal muscle mass or function. NR trials in older adults and in mitochondrial myopathy have similarly failed to improve strength, exercise capacity or mitochondrial respiration despite clear increases in muscle or blood NAD+ metabolites.

Dosage & safety

Studied doseTrials have used 250-2,000 mg/day, most commonly 500-1,000 mg/day for 6-12 weeks. NAD+ elevation plateaus around 1,000 mg/day. Since no functional benefit has been demonstrated at any dose, higher doses buy a bigger biomarker change and nothing more.
SafetyOne of the better safety profiles in this category: doses up to 2,000 mg/day for 12 weeks produced no serious adverse events, and NR has US FDA New Dietary Ingredient notification and GRAS status. Mild nausea, flushing and fatigue are occasionally reported. NR is a niacin-family compound but does not cause the classic flush at typical doses. It raises methylated metabolites (N-methylnicotinamide), theoretically drawing on methyl donors, though no clinical consequence has been shown. Caution in active malignancy, as NAD+ availability supports tumour cell proliferation. No pregnancy or lactation data. Long-term (>1 year) human data are still absent.

Scientific references

Where to buy

California Gold Nutrition, Nicotinamide Riboside Tartrate (NRT), 250 mg, 60 Veggie Capsules

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