Compare interventions

Use the same six evidence dimensions for both. This prevents a strong animal result for one product being compared with a human clinical result for another.

First intervention

versus

Second intervention

Vitamin and deficiency correction

Vitamin D

Useful human evidence

Important when deficient; extra supplementation is not a universal longevity multiplier.

Human clinical outcomes Strong

Human biomarkers Strong

Animal lifespan Preliminary

Mechanistic plausibility Strong

Safety certainty Strong

Direct longevity relevance Limited

Verdict: Vitamin D has established roles in calcium physiology and bone health, and correcting deficiency is clinically important. Large prevention trials and meta-analyses do not support the idea that progressively higher doses broadly prevent cardiovascular disease, cancer or ageing in already replete adults.

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NAD+ precursor

NMN

Early human evidence

Raises NAD-related biomarkers; broad healthspan benefits have not followed reliably.

Human clinical outcomes Preliminary

Human biomarkers Moderate

Animal lifespan Limited

Mechanistic plausibility Moderate

Safety certainty Limited

Direct longevity relevance Preliminary

Verdict: Nicotinamide mononucleotide can raise NAD-related measures in humans, which confirms biological activity. Trials have reported selected metabolic or functional effects, but results are mixed, studies are generally short, and no human evidence shows slower ageing or longer life.

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