There is a public register of the health claims that may be made about foods and food supplements in Great Britain. It is finite. Each entry names a substance, the claim wording permitted for it, and the conditions of use — usually a minimum amount that must be present for the claim to be made at all.
That register is the most useful document a British supplement buyer has never read, and the distance between what it permits and what the front of a box implies is the standing story on this shelf.
How the gap is created
Rarely by making an unauthorised claim outright. Reputable brands do not do that, and enforcement exists.
The gap opens sideways instead. A product carries a lawful, authorised claim in small type on the back — “contributes to the normal function of the immune system”, say — while the front carries a brand name, an image and a phrase that suggest something considerably more energetic. Nothing on the front is a claim in the regulatory sense. The reader assembles the impression anyway, which is the design.
The second mechanism is borrowed authority by adjacency: an ingredient with an authorised claim sits on a panel next to several that have none, and the permitted wording is applied to the product as a whole.
The check that works
Find the authorised claim wording on the pack — it is usually there, in the smallest type on the label, phrased in the flat register these claims are written in. Then check the amount.
Authorised claims carry conditions of use. For most vitamin and mineral claims the condition is that the product contains a significant amount of the nutrient, defined as a proportion of the nutrient reference value. A product below that threshold may not make the claim at all — so the presence of the claim tells you the amount cleared the bar.
The reverse is the more useful signal: a pack making energetic-sounding statements without any authorised claim wording anywhere is a pack whose ingredients may not qualify for one.
Why this framing matters
Because it is the only objective footing available on this shelf. Whether a supplement is worth buying is a judgement. Whether its label is making a claim it is entitled to make is a matter of record, and it is checkable.
Food supplements are regulated as food in Great Britain, not as medicines. They are not intended to diagnose, treat, cure or prevent any disease and are not a substitute for a varied diet or for medical care. Nothing here is medical advice.