Longevity

A peptide that homes in on the power plants of your cells to help them work better. It is now a genuine, if narrowly approved, medicine for one rare disease, but unproven for the anti-ageing uses it is hyped for.

Grade B · Human trials exist but are incomplete.

A natural building-block your own cells use to make haem and fuel your mitochondria. It's a licensed medicine — but as a glow-in-the-dark dye for brain-tumour surgery, not as the energy-and-metabolism supplement it's sold as.

Grade C · Some human data, far from settled.

Glutathione is the body's main built-in antioxidant. The biology is real, but swallowing or injecting it as an anti-ageing or skin-lightening treatment rests on thin human evidence and, for IV use, real safety warnings.

Grade C · Some human data, far from settled.

A coenzyme your cells already make and use for energy and DNA repair; levels fall with age, so people take it (or its precursors) hoping to turn back the clock, but the human anti-ageing evidence is thin.

Grade C · Some human data, far from settled.

A NAD+ building-block sold as an anti-ageing supplement; it genuinely raises NAD+ levels in human blood, but whether that does anything meaningful for ageing or healthspan is still unproven.

Grade C · Some human data, far from settled.

A form of vitamin B3 that genuinely raises the cellular fuel-handling molecule NAD+ in people, sold as an anti-ageing supplement, but human trials have mostly failed to show it makes you meaningfully healthier.

Grade C · Some human data, far from settled.

A Soviet-era extract of calf thymus glands, claimed to "reset" an ageing immune system — backed by decades of striking-looking Russian longevity data that almost nobody outside Russia has been able to check or repeat.

Grade C · Some human data, far from settled.

Epitalon is a lab-made four-amino-acid peptide promoted as an anti-ageing telomere treatment, but the human evidence behind those claims is thin and largely from one research group.

Grade D · No meaningful human evidence yet.

A tiny protective peptide your own mitochondria make, which looks fascinating in lab animals and correlates with healthy ageing in people, but has never been properly tested as a drug in humans.

Grade D · No meaningful human evidence yet.

A tiny peptide your own mitochondria produce during exercise, promising for metabolism in mice, but in humans only measured as a biomarker rather than proven to work as an injected drug.

Grade D · No meaningful human evidence yet.

Vilon is a lab-made two-amino-acid peptide (Lys-Glu) from the Russian 'bioregulator' family, promoted for immune ageing and longevity, but the human evidence is essentially limited to cells in a dish.

Grade D · No meaningful human evidence yet.