Reviews are graded A to D against the published methodology. No claim in this journal currently holds grade A on an interventional basis, and one prognostic claim does. Grades attach to the specific claim stated at the top of each review, so the same compound may carry different grades for different assertions about it.
- 01
NAD precursors: nicotinamide mononucleotide and nicotinamide riboside
Raising blood NAD metabolites is well demonstrated. Changing the trajectory of human ageing is not the same claim, and it is the one the supplement market makes.
Grade D · Intervention claim - 02
Metformin for healthspan
The best characterised drug in the field, and still without a trial that tests the claim being made for it. The observational signal is real and so are the reasons to distrust it.
Grade C · Intervention claim - 03
Rapamycin and mTOR
The most convincing animal lifespan data in the field, attached to an immunosuppressant with real risks and no long human ageing trial. Both halves of that sentence matter.
Grade D · Intervention claim - 04
Senolytics: the current state
Clearing senescent cells is one of the better ideas in ageing biology. Whether it can be done safely and usefully in a person is an open question with early answers only.
Grade D · Intervention claim - 05
VO2 max as a longevity marker
The single measurement most consistently associated with how long people live. That is a prognostic claim, and it should not be confused with proof that raising it causes the benefit.
Grade A · Prognostic claim - 06
Resistance training and mortality
Strong randomised evidence for function, strength and falls. Weaker observational evidence for mortality, resting on self-reported exposure and an odd shape at the top of the range.
Grade B · Prognostic claim - 07
Sleep architecture and ageing
Sleep changes measurably with age and poor sleep tracks poor outcomes. Which way the causal arrow points, and whether treating sleep changes anything downstream, is much less clear.
Grade C · Prognostic claim - 08
Time-restricted eating
One of the few interventions here with genuine randomised human evidence. The trials are short, and when calories are matched the additional effect of the window is small.
Grade C · Intervention claim