How to Choose a Probiotic: CFU Count, Strains and Timing Explained

Quick answer: When comparing probiotics, the CFU (colony forming units) count and the specific named strains matter more than brand name or price. Look for a product that names its strains specifically rather than just "probiotic blend," states the CFU count guaranteed through the end of shelf life (not just at manufacture), and matches your actual reason for taking it.

What CFU Actually Means

CFU stands for colony forming units - essentially, how many live bacteria are in each dose. Higher isn't automatically better; what matters more is whether the CFU count is guaranteed at the point you take it. Some products only guarantee CFU at time of manufacture, which is a meaningfully weaker claim, since live cultures can decline over shelf life depending on formulation and storage.

Why the Specific Strain Matters

"Probiotic" isn't one single thing - it covers many different species and strains of bacteria (Lactobacillus rhamnosus and Bifidobacterium lactis, for example), and different strains have been studied for different things. A product listing specific named strains, rather than just "multi-strain blend," tells you more about what you're actually taking.

Prebiotic vs Probiotic - Quick Clarification

Probiotics are the live bacteria themselves. Prebiotics are the fibre and compounds that feed bacteria already in your gut, including any probiotic strains you're introducing. Some products combine both, which isn't necessary but can be a reasonable convenience over taking two separate supplements.

Timing and Storage

Some probiotics need to be taken with food, some on an empty stomach, and some strains are more heat-stable than others - which affects whether a product needs refrigeration or is shelf-stable. Always follow the specific product's instructions rather than assuming one rule applies across all probiotics.

Shop Probiotics at Powersup

Our range includes Optibac (one of the most recommended probiotic brands by UK pharmacists), Wellgard's Gutstar (16-strain, 20 billion CFU), and Womenli's Her V-Flora (formulated for women's gut and intimate flora balance). Browse the full range in Gut Health & Prebiotics.

FAQ

How long before I notice a difference?

This varies a lot by person and reason for taking it - some people notice changes within a couple of weeks, for others it takes longer or is less noticeable day-to-day.

Do I need to take probiotics with antibiotics?

Many people do take them around an antibiotic course, though timing relative to the antibiotic dose matters - check product guidance or ask a pharmacist.

Can I take probiotics every day, long-term?

Yes, they're commonly taken as an ongoing daily supplement rather than a short course.

Is a higher CFU count always better?

Not necessarily - strain match and guaranteed potency through shelf life matter more than chasing the highest number on the label.