Probiotic Supplements

What are probiotics?

The NHS describes probiotics as live bacteria and yeasts promoted as having various health benefits, usually sold in yoghurts and food supplements. They are often called "good" or "friendly" bacteria.

This collection includes capsules with Lactobacillus and Bifidobacterium cultures, the yeast Saccharomyces boulardii, a vegan probiotic, gummies for adults and children, and some products that are not probiotics at all, such as prebiotic fibres and digestive enzymes, which we explain below.

Do probiotics work?

It depends on the strain and the reason, and the evidence is mixed. The NHS says there's some evidence that probiotics may be helpful in some cases, such as easing some symptoms of irritable bowel syndrome, but there's no evidence they help eczema.

The British Dietetic Association says if you are healthy, it is unlikely a probiotic supplement will be beneficial. "Where evidence is limited or inconclusive, we should say so openly," says Andy Arshad, who runs SupplementHQ.

Why can't probiotics make health claims?

Because none have been authorised. The GB list of authorised health claims has no general claim for probiotics; the only related entry is that live cultures in yoghurt or fermented milk improve lactose digestion, which applies to yoghurt with specific cultures, not to capsules.

The NHS also points out that probiotics are generally classed as food rather than medicine, so it can't always be sure a product contains the bacteria stated, in large enough numbers, or that they survive to reach the gut. That's why we don't say any product here supports digestion or immunity.

What does CFU mean, and is more better?

CFU (colony forming units) is the number of live, active microorganisms in a dose, often written in billions. The US National Institutes of Health says higher CFU counts alone do not necessarily mean that the product has greater health benefits.

Look for a CFU figure stated for the end of the shelf life, not just at the time of manufacture. "Adding more ingredients doesn't automatically make a product more effective. Each ingredient needs a clear purpose, an appropriate dose and evidence supporting its intended use," says Andy.

Why do probiotic strains matter?

Probiotics are named by genus, species and strain, for example Lactobacillus (genus) acidophilus (species) followed by a strain code. The NIH says the effects vary depending on the probiotic strain used, so results for one strain can't be assumed for another, even within the same species.

So a label that only says "Lactobacillus" or "a blend of 10 cultures" tells you less than one that lists each strain and its amount. Compare products on what they disclose.

Probiotics or prebiotics: what's the difference?

Probiotics are live microorganisms; prebiotics are not alive. The BDA says prebiotics are like fertiliser for our gut microbes, feeding the bacteria already there.

Prebiotic fibres such as inulin from chicory root also appear in our fibre and digestive enzymes collection. Some products combine both and are sometimes called synbiotics.

How should probiotics be stored?

Follow the label. The NIH says some probiotics need to be kept in the refrigerator, but others can be stored at room temperature, and the BDA advises storing them as the package recommends.

Live cultures can lose numbers over time, especially in heat, so check the best-before date and storage instructions when comparing.

Are probiotics safe?

For most people, yes: the NHS says for most people, probiotics appear to be safe. But if you have a health condition or a weakened immune system, the NHS says you should talk to a doctor before taking any probiotic supplement.

Speak to your GP or pharmacist if you're pregnant or breastfeeding, take medication, or want to give a probiotic to a child. Children's products, such as the kids' probiotic gummies here, should be kept out of reach.

How to compare probiotics on value

Compare the cost per daily dose, then check what that dose provides: named strains, CFU at the end of shelf life and the storage needed.

How to compare value (example figures, not real products): a £15 pot of 30 capsules, one a day, costs 50p a day. A £24 pot of 60 capsules, two a day, costs 80p a day. If the second lists fewer strains and no CFU figure at the end of shelf life, the higher price is not buying more information. Go back to all vitamins and supplements, or read our guide to reading a supplement label.

We sell the products on this page. That's our commercial interest, and it's why we show the evidence alongside them. This page is general information for adults, not personalised medical advice. Food supplements should not replace a varied, balanced diet.

Written by Andy Arshad, SupplementHQ. Last reviewed 11 October 2026.