FAQs
Probiotic supplement FAQs
Short, plain-English answers to the questions UK shoppers ask most about probiotic supplements, from strains and CFU counts to labels, storage and safety. If your question is not here, ask us using the form on this page.
- Basics, choosing and CFU
- Labels, storage and quality
- Safety in general terms
Basics
Probiotic basics
What are probiotic supplements?
A widely used definition describes probiotics as live microorganisms that, when taken in adequate amounts, can benefit the person taking them. Supplements supply them as capsules, powders, gummies, chewables or drops, and in Great Britain they are sold as food supplements.
What is the difference between probiotics and prebiotics?
Probiotics are live microorganisms, while prebiotics are fibres such as inulin, FOS and GOS that some products add alongside them. A product that combines both is often called a synbiotic, as our strains guide explains.
Which microorganisms are used in probiotics?
Most products use lactobacilli, bifidobacteria, the yeast Saccharomyces boulardii or spore-forming Bacillus species such as Bacillus coagulans. Our guide to probiotic strains describes each group.
Why does the strain matter?
Research on one strain does not automatically apply to another strain of the same species. Two products can list the same species but contain different strains, so the full strain name is one of the most useful details on a label.
Are probiotics classed as medicines?
No. In Great Britain, probiotics are sold as food supplements and follow food law. No health claims are currently authorised for probiotics, so packs should not claim that the cultures have any effect on health.
Choosing
Choosing a probiotic supplement
How do I choose a probiotic supplement?
Start with the full strain names, then check how the CFU count is stated, the format, dietary suitability and storage instructions. Our guide on how to choose a probiotic supplement takes you through each check.
Is a higher CFU count better?
Not automatically. A bigger number does not make a product more suitable, and what matters more is whether the count is stated until the best-before date or only at manufacture.
Is a multi-strain probiotic better than a single strain?
Not necessarily. Because research is strain-specific, a product with a few fully named strains can tell you more than a long list of species without strain codes.
Are capsules better than gummies or powders?
Each type suits different people. Capsules are convenient, powders mix into food or drink and gummies usually rely on heat-tolerant spore-formers. You can compare them on our probiotic types page.
Can I find a vegan probiotic?
Many probiotics use plant-based capsule shells or pectin gummies, but some cultures are grown on dairy-based media and some gummies contain gelatine. Check the ingredients, the allergens in bold and any vegan or vegetarian statement.
Labels
Labels, strains and CFU
What does CFU mean?
CFU stands for colony forming units, an estimate of the live microbes in each serving. Our guide to understanding CFU counts explains the figure and the date it applies to.
What does "at time of manufacture" mean on a label?
It means the CFU count was measured when the product was made, and fewer live cultures may remain by the best-before date. A count stated until the best-before date tells you more.
Why do strain names differ between labels?
Many Lactobacillus species were renamed in 2020, so one pack may say Lacticaseibacillus rhamnosus and another Lactobacillus rhamnosus. Both names refer to the same species.
Why do probiotic labels not mention health benefits?
No health claims are currently authorised for probiotics in Great Britain. If a pack says vitamin D contributes to the normal function of the immune system, that claim relates to the added vitamin, not the cultures, as our label guide explains.
What must a UK probiotic label include?
It must say "food supplement" and show the daily dose, a do-not-exceed warning, a varied-diet statement and a keep-out-of-reach-of-children statement. Ingredients with allergens emphasised, a best-before date, storage conditions, a batch code and the business name and address are also required. Our guide to reading a probiotic label covers each item.
Storage
Storage and quality
Do probiotics need to be kept in the fridge?
Some do and some do not. Follow the storage instructions on the pack, because some products need refrigerating after opening while others are made to stay stable at room temperature.
Can I use a probiotic after its best-before date?
The count on the label only applies up to the best-before date, and live cultures keep declining after it. For that reason, it makes sense to use a probiotic within its date.
How should I store probiotics when travelling?
Keep them cool and dry, away from direct sun and hot cars, and in their original packaging. Our storage and shelf life guide has more detail.
How can I judge the quality of a probiotic?
Look for fully named strains, a CFU count stated until the best-before date, protective packaging and clear storage instructions. Our quality page explains what each sign tells you.
Safety
Safety, dosing and this site
Are probiotics safe?
Probiotics are generally considered safe for healthy adults. Some people notice mild wind or bloating at first, and added fibres such as inulin can cause wind in some people.
Who should check with a pharmacist or GP first?
Speak to a pharmacist or GP first if you are pregnant or breastfeeding, have a weakened immune system or a serious illness, take medication including antibiotics, or are buying for a baby or child.
How much should I take?
Follow the recommended daily dose on the label and do not exceed it. We cannot give personal dosing advice, so ask a pharmacist if you are unsure.
Do you sell or recommend probiotics?
No. Probiotic Supplements UK is an independent information site, and we do not sell, manufacture, rank or review supplements or name brands in our guides.
Can I ask you a question?
Yes. Ask us a question using the form on this page or email info@probioticsupplements.co.uk, and we will reply with general, brand-neutral information.
We answer the questions these FAQs do not cover
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