Evidence · 9 min · 30 July 2026

The four supplements worth the money, and why the rest are not

I sell none of these and take commission from nobody, which is the only reason this list is short.

There are four with enough evidence behind them to be worth discussing for most field-sport athletes, and a very long tail of products with a mechanism, a press release and no outcome data.

The short list

Creatine monohydrate, caffeine, and — where a genuine deficiency is shown on bloods rather than assumed — iron and vitamin D. That is it. Everything else is either situational or unproven, and I will tell you which.

Why the list is short

Because the bar is an effect on performance in trained athletes, measured properly, replicated. A great many products clear the bar of 'plausible mechanism' and almost none clear that one.

Contamination is a real risk

If you are tested, use only batch-tested products. Contamination with banned substances is not hypothetical and the consequence is yours, not the manufacturer's.

What this is not

General information, not a recommendation for you. Anything you take is worth discussing with your doctor, particularly if you take medication.

General information, not advice about an individual. Every figure on this site is illustrative. What I can and cannot tell you →