Storage instructions
Live cultures decline with heat, moisture and oxygen. Check whether the pack asks you to refrigerate it after opening. Our guide to probiotic storage and shelf life explains more.
Labels, storage and quality
How to judge probiotic quality before you buy
You cannot test a probiotic at home, but the label and packaging tell you a great deal about how carefully it has been made. This guide explains how to judge probiotic quality using details any shopper can check, with a probiotic quality checklist and the red flags worth knowing.
- CFU stated until the best-before date
- Full strain names and a batch code
- Realistic wording with no medical claims
What you can check
How to judge probiotic quality: start with the CFU count
CFU stands for colony forming units, an estimate of how many live microbes a serving contains. Live cultures slowly decline after they are made, so the useful question is when the stated count applies. Some labels give the count at the time of manufacture, while others state that it applies until the best-before date, which tells you much more about what is likely to be in the pack when you take it.
A bigger number is not automatically better. A named strain with a count stated to the end of shelf life tells you more than a larger figure with no date. Our guide to understanding CFU counts explains per-serving figures and multi-strain totals in more detail.
Look for full strain names
A full strain name has a genus, a species and a strain code made of letters or numbers. Research on one strain does not automatically apply to another strain of the same species, so a label that stops at the species name tells you less. Our guide to probiotic strains explains strain codes and the 2020 renaming of many Lactobacillus species.
On the pack
Storage, packaging and the details a label must carry
Every food supplement sold in Great Britain has to carry certain information. These parts say most about how a probiotic has been handled.
Protective packaging
Foil blisters, sachets and bottles lined with a desiccant help keep moisture out. A tub that is opened every day gives the cultures less protection, so its storage advice matters more.
Batch code and business address
A batch code lets the business trace a product back to its production run if a problem comes to light. The label should also give the name and address of the business responsible, so you know who to contact.
Dietary and allergen information
Allergens should be emphasised in the ingredients list. Check whether capsule shells are vegan or vegetarian and whether the cultures were grown on dairy-based media, as some are.
Claims and testing
Realistic wording and third-party testing statements
In Great Britain, probiotics are sold as food supplements, and no health claims are currently authorised for them. A claim such as "vitamin D contributes to the normal function of the immune system" relates to an added vitamin, not to the cultures. A pack that promises a medical outcome, or names an illness a probiotic is meant to fix, is making a claim the rules do not allow.
Some labels mention independent or third-party testing. This can show that a business checks its products, but it is worth reading the statement closely. A testing statement tells you a product was checked for something, such as its live count or contaminants, and it does not show that the product will work for you. Our guide on how to read a probiotic label explains the other wording you will see on pack. Probiotic Supplements UK does not test products, so we cannot confirm any statement a brand makes.
Questions to ask about a testing statement
- Who carried out the testing
- What was tested, such as the live count, strain identity or contaminants
- Whether every batch is tested or only an early sample
- Whether the business will share results if you email to ask
If a statement answers none of these, read it as general reassurance rather than evidence, or ask us a question about it.
Before you buy
Probiotic quality checklist
Use this probiotic quality checklist in a shop or on a product page before you buy.
- The CFU count is stated until the best-before date
- Each strain is named with its genus, species and strain code
- Packaging protects against moisture, such as foil blisters or a desiccant
- A batch code and best-before date are printed on the pack
- The business name and address are given
- Allergens are emphasised and dietary suitability is stated
- The words "food supplement" appear, with a daily dose and a do-not-exceed warning
- Wording describes ingredients rather than promising results
Red flags
Red flags worth noticing on a probiotic label
Medical claims
Wording that names an illness or promises to heal a condition goes beyond what is permitted for probiotics.
Vague strain information
Species names with no strain codes, or a blend with no breakdown, make it hard to compare one product with another.
A count with no date
A CFU figure that applies only at manufacture, or has no stated date at all, says little about what remains later.
Missing basics
No batch code, business address or best-before date suggests the label does not meet basic requirements.
Testing claims without detail
Phrases such as 'lab tested' or 'clinically proven' with no explanation of what was tested, or by whom.
FAQs
Probiotic quality questions
Is a higher CFU count a sign of better quality?
Not on its own. What matters more is whether the count is stated until the best-before date and whether the strains are named in full. A large figure that only applies at manufacture says less about what you will actually take.
What does third-party tested mean on a probiotic?
It usually means a laboratory outside the business checked the product for something, such as its live count or contaminants. It does not show that the product will work for you, and it may not mean every batch is tested. You can email the business to ask what was tested and how often.
Do probiotics need to be kept in the fridge?
Some do and some do not. Follow the storage instructions on the label, which may ask you to refrigerate the product after opening. Many other products are designed to be kept somewhere cool and dry.
Should I speak to someone before taking a probiotic?
Probiotics are generally considered safe for healthy adults, and some people notice mild wind or bloating at 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, speak to a pharmacist or GP first.
Ask us about a label you are unsure of
Send us the wording that puzzles you, such as a CFU figure or a testing statement. We reply by email with a plain-English explanation and never recommend brands.