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

Antioxidant precursor and medicine

N-acetylcysteine (NAC)

Mostly indirect evidence

Established clinical uses do not automatically translate into routine longevity benefit.

Human clinical outcomes Moderate

Human biomarkers Moderate

Animal lifespan Preliminary

Mechanistic plausibility Strong

Safety certainty Moderate

Direct longevity relevance None

Verdict: NAC is a medicine in some settings and a supplement in others. It is an established antidote for paracetamol poisoning and a mucolytic, with additional research across respiratory, psychiatric and metabolic conditions. Evidence that routine NAC supplementation slows ageing in healthy people is absent.

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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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