Probiotic, live cultures, biotic. Which is regulated in the UK?

None of them is an authorised claim on its own in Great Britain. Contains live cultures states what is in the pot, so it needs no approval. Probiotic and prebiotic count as health claims, and every claim on the GB register using either word is marked not authorised. Synbiotic and postbiotic aren’t on the register at all.

So the word that sounds most scientific is the one with the least legal standing, and the dullest phrase on the pot is the one that is safest to print.

Is probiotic a regulated word on UK food labels?

Yes. The government’s guidance on claims gives probiotic as an example of a health claim, which it defines as anything that states, suggests or implies a relationship between a food and health. Health claims are prohibited on food unless they are authorised.

In the version of the register dated 19 May 2026, the word appears more than a hundred times, and every one of those claims is recorded as not authorised.

That doesn’t mean the word never appears. Under the advertising rules, probiotic counts at the least as a general health claim, and a general claim is allowed only when a specific authorised health claim that is closely related sits beside it. If the wording goes further and explains what the bacteria do, it can become a specific health claim, which would need its own place on the register. In 2023 the advertising regulator looked at an advert for apple cider vinegar that talked about live probiotics to boost gut health, and ruled the claims a problem because no authorised claim went with them.

Why can a yoghurt say contains live cultures?

Because it describes the contents rather than promising anything. Statements of fact that don’t imply the food is beneficial are not claims under the regulation, in the same way that contains 5g of fat isn’t.

There is one authorised health claim for those cultures, and it is narrow. Live cultures in yoghurt or fermented milk improve lactose digestion of the product in people who have difficulty digesting lactose. To carry it, the yoghurt or fermented milk needs at least 100 million colony forming units of live starter cultures per gram, from the two named yoghurt starter species. Nothing on the register authorises a claim about immunity, bloating or gut health for live cultures. What a yoghurt pot is allowed to say beyond that is in the gut friendly yoghurt aisle.

What about prebiotic, synbiotic and postbiotic?

Prebiotic is treated much like probiotic. The word turns up in thirty rows of the register, in applications for fibres such as inulin, oligosaccharides, acacia gum and polydextrose, and all thirty are recorded as not authorised.

A prebiotic claim can still be lawful in an advert when it is general and an authorised claim beside it is used properly. In 2023 the advertising regulator looked at a breakfast cereal that described prebiotic goodness for your gut. It accepted that the general claims came with a relevant authorised claim about chicory root inulin, but found the cereal didn’t meet that claim’s conditions of use, and it ruled that a line about increasing levels of important bacteria in your gut was an unauthorised specific claim. The register’s authorised claim for chicory inulin is about normal bowel function, and its condition is a daily intake of 12g.

Synbiotic and postbiotic are newer words. Neither appears anywhere in the register, authorised or not, so there is no approved claim to stand behind either.

Does a probiotic label tell you the bacteria will reach your gut?

No, and this is the part I’d want every shopper to know. Probiotics are generally classed as food rather than medicine, so they don’t go through the testing medicines do. Because of the way they are regulated, the NHS’s own page on them says you can’t always be sure the product contains the bacteria stated on the label, contains enough to have an effect, or that the bacteria survive long enough to reach your gut.

Different types of probiotic may have different effects, and little is known about which types are best. There is some evidence they may help in some cases, such as easing some symptoms of IBS, and little evidence behind many of the health claims made about them.

Fermented foods are a separate question again. Kefir and kombucha may contain beneficial microorganisms, but they are not considered probiotics, because the scientific evidence on their health benefits isn’t there.

What should you look for on the pack?

The exact words, and what sits next to them. A pot that says contains live cultures and stops there is describing itself. A pot or bottle that says probiotic, or anything about your gut, should have an authorised claim close by; if it doesn’t, the vague word is carrying the sale on its own. If you want to check a claim against the register yourself, how to check a health claim walks through the spreadsheet step by step, and the label test is a quick way to see how much of this you’d spot in the chiller aisle.

I’m describing the law here, not rating any product. If you are thinking about a probiotic supplement and you have a health condition or a weakened immune system, talk to a doctor first. Supplements and protocols are something I’ll leave to the people looking after you; what to read before a gut health supplement explains why.

When a label isn’t the answer

No pot can tell you why your gut is unhappy. See a GP if you feel bloated regularly, if you’ve tried changing your diet but keep feeling bloated, or if you have bloating with unintentional weight loss or blood in your poo. Ask for an urgent GP appointment or call 111 if bloating comes with vomiting, diarrhoea or constipation, a stomach ache, a high temperature, a swelling or lump in your tummy, or if you cannot pee, poo or fart. That is most of the NHS list for bloating, and the full list is on its bloating page.