What’s worth taking. What isn’t.
Most supplements sold for healthy ageing do nothing you can measure. A few genuinely earn their place. Every one here is graded by the strength of human trial evidence — including the famous names that grade badly.
How we grade evidence
Every compound and protocol on this site carries one of three grades. The grade describes the strength of the human evidence, not how promising the mechanism looks or how much we like it. Grades move when the literature moves — down as often as up.
- Grade AStrong human trial evidence
- Multiple randomised controlled trials in humans, ideally with a meta-analysis, showing a consistent effect on an outcome that matters — not just on a biomarker. Safety at the stated dose is well characterised.
- Grade BPromising but incomplete
- Some randomised human evidence, but the trials are small, short, conflicting, or measure surrogate endpoints. A reasonable bet with real uncertainty attached.
- Grade CMechanism, animals, or observation only
- The rationale rests on cell and animal work, on epidemiology, or on human trials that moved a biomarker without moving an outcome. Interesting, unproven, and priced accordingly.
A high grade is not a recommendation and a low grade is not a dismissal. Creatine and NMN are both worth understanding; only one of them has the trial record to back the claims made for it.
Taking things without measuring is guessing.
A supplement either moves a marker you can test, or you are taking it on faith. Get the baseline first, then let the retest tell you what is working.
The Sunday briefing
One email a week: what changed in the evidence, what it means for the markers you track, and the occasional thing worth stopping. No spam, unsubscribe anytime.