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

Skin and connective tissue

Collagen peptides

Useful human evidence

Modest symptom or appearance benefits are plausible; this is not an anti-ageing intervention in the broad sense.

Human clinical outcomes Moderate

Human biomarkers Limited

Animal lifespan None

Mechanistic plausibility Moderate

Safety certainty Moderate

Direct longevity relevance Preliminary

Verdict: Hydrolysed collagen has human trial evidence for modest improvements in skin hydration or elasticity and for some joint symptoms. These are specific outcomes. They do not show systemic rejuvenation, and commercial formulations vary.

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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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