GuideGut & digestion

Probiotics: Strains & CFU Decoded

Choosing a probiotic can feel like reading a foreign language: genus names, strain codes and billions of CFU. This guide decodes the label, explains why strain matters, how to store live cultures in Gulf heat and who should ask a doctor first. No health claim for probiotics is authorised in the EU.

By the Healthana Editorial Team · Last reviewed: 01 Nov 2026

Daily reference intake (NRV)No NRV set
Upper limit for adultsNo upper limit set; see guidance below

What probiotics are

Probiotics are live microorganisms, mostly bacteria and some yeasts, that are added to supplements and foods such as yoghurt, laban and kefir. Your gut already hosts trillions of microbes, often called the gut microbiota, which help break down fibre and interact with the gut lining. Probiotic products add specific strains to that community, usually for a short time while they pass through.

Research has looked at many uses, but effects are strain-specific: a result for one strain does not apply to another strain, even of the same species. For most uses, scientists do not yet know which strains help, at what amount, or for whom. No health claim for probiotics is authorised in the EU, and regulators in several EU countries regard the word probiotic itself as an implied claim on foods. We therefore explain labels and safety only.

Forms you'll see on labels

FormWhat to know
Lactobacillus and related generaMany species were renamed in 2020, so you may see Lacticaseibacillus rhamnosus or Lactiplantibacillus plantarum where older labels said Lactobacillus.
BifidobacteriumAnother common genus, for example Bifidobacterium lactis or longum.
Saccharomyces boulardiiA probiotic yeast, not a bacterium. Antifungal medicines can affect it.
Bacillus sporesSpore-forming bacteria such as Bacillus coagulans, which are more tolerant of heat.
SynbioticsProbiotics combined with a prebiotic fibre such as inulin.
Tyndallized or heat-killed strainsBacteria inactivated by heat. They are not live, so they are not probiotics in the strict sense.
Multi-strain blendsSeveral strains in one capsule. More strains is not automatically more useful.

How much: CFU and what the numbers mean

  • NRV and upper limit: none set, as probiotics are not nutrients.
  • CFU: colony-forming units, an estimate of live cells. Many supplements contain about 1–10 billion CFU per dose; some contain 50 billion or more. A higher count does not necessarily mean a more effective product.
  • At manufacture vs end of shelf life: cultures die over time. A count stated at the end of shelf life is more useful than one stated at manufacture.
  • Food sources: yoghurt, laban, kefir, some cheeses and fermented vegetables can contain live cultures, though strain and amount are rarely stated.

Who should check with a doctor or pharmacist first

  • Anyone with a weakened immune system, for example from medicines that suppress immunity or chemotherapy.
  • People who are seriously ill, in hospital, or have a central venous line.
  • Premature or very young babies: serious infections have been reported in premature infants given probiotics. Never give a probiotic to a baby without medical advice.
  • Children: check the age on the pack and ask a doctor or pharmacist; some products are made for specific ages.
  • Pregnant or breastfeeding women, and anyone with a serious underlying health condition.
  • Anyone on a course of antibiotics or antifungals: ask a pharmacist how to space doses, as these medicines can affect bacteria or yeasts in the product.

How to read the label

  • Full strain name: look for genus, species and a strain code, for example Lacticaseibacillus rhamnosus GG. The strain code links the product to specific research.
  • CFU and the date it applies to: look for a count stated for the end of shelf life rather than at manufacture.
  • Per capsule vs per serving: some products need two capsules for the stated count.
  • Storage instructions: refrigerate if the label says so.
  • Other ingredients: prebiotic fibres, cranberry or vitamins may be added. Check allergens such as milk or soy.

Compare capsules, gummies and kids' formats in our probiotics collection.

Bahrain & GCC notes

Heat is the main enemy of live cultures. Do not leave probiotics in a parked car, and keep refrigerated products in the fridge as soon as you get home. Shelf-stable products still do better in a cool, dry cupboard away from the kitchen stove. When travelling in summer, carry blister-packed capsules rather than bottles that are opened often. More formats sit in our probiotics range.

Sundance Probiotic-14 with Prebiotic 25 billion cultures, 30 Vegetable Capsules
Label check

Reading a real label

Sundance Probiotic-14 with Prebiotic 25 billion cultures, 30 Vegetable Capsules
On the labelWhat it means
25 billion cultures per 2 capsulesCounted at the time of manufacture, as the label says
14 strainsEach strain is named on the label
100 mg inulinThe prebiotic fibre in the capsule
30 capsules, 2 a dayA 15-day supply
Figures from the product's own label. Always check the pack in your hand.See this product
EU-authorised health claims

    No health claim is authorised for this ingredient in the EU. We share facts only.

    Frequently asked questions

    Is a higher CFU count better?

    Not necessarily. Effects depend on the specific strain and amount studied, and a higher count does not automatically mean a more effective product.

    Why do strain codes matter?

    Research results apply to specific strains, identified by codes such as GG or BB-12. Without a strain code, you cannot link a product to any study.

    Do probiotics need to be refrigerated?

    Some do and some are shelf-stable. Follow the storage instructions on the label, and keep all probiotics away from heat.

    Are heat-killed bacteria the same as probiotics?

    No. Tyndallized or heat-killed bacteria are not alive, so they do not meet the usual definition of a probiotic.

    Is there an authorised EU health claim for probiotics?

    No. No health claim for probiotics is authorised in the EU.

    This page is general information from Healthana, not medical advice. Food supplements should not replace a varied, balanced diet and a healthy lifestyle. Speak to your doctor or pharmacist if you are pregnant or breastfeeding, take medication or have a medical condition. Editorial policy
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