The supplements worth your money, and the ones that are not

The three that earn their place for almost everyone

Creatine monohydrate is the most studied ergogenic aid in existence, it is cheap, and the evidence in women is good — for strength, for training quality, and increasingly for cognition and mood. Three to five grams a day, no loading phase required, and no, it does not make you bulky or damage your kidneys.

Vitamin D, from October to April in Britain, because the skin cannot make it at our latitude in winter. And protein powder, which is not really a supplement at all — it is food in a convenient shape, and worth having only if you are otherwise missing the target.

The situational ones

Iron, only where a test shows depletion, because supplementing without one is both pointless and potentially harmful. Omega-3, where diet is genuinely short of oily fish. Magnesium, where sleep or cramping is a real complaint, though the evidence is softer than the marketing. Caffeine, which is a genuine performance aid and requires no capsule.

The common thread is that each answers a specific question. Buying them speculatively is how a cupboard fills with expensive urine.

What I do not sell, and why

Fat burners, detox products and anything promising to reset your metabolism: no mechanism, no evidence, and in the case of stimulant blends, real risk. BCAAs, which are redundant if your protein intake is adequate. Most greens powders, which are a costly way to not eat vegetables.

Collagen and NMN sit in an honest middle: the collagen evidence for tendon and skin is early but not absurd, and NMN is genuinely interesting research that has not yet earned a confident recommendation. I will say that plainly rather than sell either on the strength of a headline.

• 01

  Start with creatine and vitamin D, in that order

  If you buy two things
• 02

  Test before iron, always

  Non-negotiable
• 03

  Treat anything promising a metabolic reset as marketing

  The filter