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Is there such a thing as too many probiotics?

Is there such a thing as too many probiotics?

There are hundreds of different probiotic supplements out there. Some contain billions of bacteria in each capsule. So why are there so many? And how many probiotic bacteria do you actually need?

Lifestyle insight
Reading time: 3 minutes

Why are there so many different probiotics?

Probiotics are ‘live microorganisms that confer a health effect when consumed in adequate amounts.1

Researchers are still identifying new probiotics, and while they may never find and identify every single probiotic strain out there, the number of currently known probiotic strains is almost at 8,000.2

Probiotics are identified by their specific strain, which includes the genus, the species, and the strain.

There are seven core families (or genus) most often used in probiotic products. There are:

  • Lactobacillus
  • Bifidobacterium
  • Saccharomyces
  • Streptococcus
  • Enterococcus
  • Escherichia, and 
  • Bacillus3


Within each of these families there can be many different species, which then include many different subspecies or strains.

The effects and health benefits of probiotics are strain-specific. The benefits seen in a clinical study of a specific strain will not be the same for any other strain – even if they are closely related.4

There are thousands of individual probiotic strains out there, and even more probiotic supplements available with those probiotics in many different combinations. A single strain may exhibit different benefits when used individually and in combination.5

It is important to ensure that you are choosing the right probiotic, at the right dose which has been clinically studied for the health benefit you are trying to achieve.


How many CFUs can I take in a day?

Probiotic doses are measured in colony forming units (CFUs), which means the number of live bacteria in each dose.

Many probiotic supplements contain 1 to 10 billion CFU per dose, but some products contain up to 50 billion CFU or more. However, a higher CFU count doesn’t mean the product is more effective.3

The number of CFUs you need to take in a day will vary from person-to-person and is dependent on the type of probiotic you are taking, the health benefit you are trying to achieve, the product formulation and the quality of the product you are taking.6

It is best to use the recommended dose of a product that has been clinically-trialled and shown to have the benefit you are looking for,

However, depending on a person's health condition, most people can take a maximum daily dose equivalent to 400 billion CFUs.


Questions to ask your healthcare professional

  • Will probiotics help my symptoms?
  • Which probiotic strain is best for my health concerns?
  • Can I take probiotics with my current medications?
  • Are there any known or expected side-effects from taking probiotics?
  • Are probiotics safe to take if I am pregnant or breast-feeding?
  • How do I know if my probiotic has been clinically-trialled?



  1. Chong HX, et al. Lactobacillus plantarum DR7 alleviates stress and anxiety in adults: a randomised, double-blind, placebo-controlled study. Benef Microbes. 2019; 10(4): 355-373.
  2. Boyers L. A Guide To The Most Common Types Of Probiotics & What They Do. MindBodyGreen Health. 2022. https://www.mindbodygreen.com/articles/guide-to-most-common-probiotic-strains-and-what-they-do/ - accessed 22-May-22
  3. NIH. Probiotics – Factsheet for Health Professionals. 2021. https://ods.od.nih.gov/factsheets/Probiotics-HealthProfessional/ - accessed 22-May-22
  4. Ebner S, Smug LN, Kneifel W, Salminen SJ, Sanders ME. Probiotics in dietary guidelines and clinical recommendations outside the European Union. World J Gastroenterol 2014; 20(43): 16095-16100
  5. Mishra S, Acharya S. A Brief Overview on Probiotics: The Health friendly Microbes. Biomed Pharmacol J 2021;14(4).
  6. Ghoshal M. How Long Does It Take for Probiotics to Work? Healthline. 2020. https://www.healthline.com/health/probiotics-and-digestive-health/how-long-does-it-take-for-probiotics-to-work - Accessed 22-May-22

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