Exploring the World's Most Researched Probiotic Strains

Highlight strains well researched for  

Aims of the Probiotics Database

More and more research demonstrates that the benefits of probiotics are seen at the level of the strain – ie. one strain may help with vaginal health, whilst another strain (even of the same species) might be much better researched for antibiotic associated diarrhoea.

At the same time, in this relatively novel field of health, a huge level of misunderstanding exists with regards to what a probiotic strain is – with many people thinking that Lactobacillus acidophilus is a probiotic strain – whereas it is in fact a species of bacteria, and identification at a strain level is imperative.

With this database we therefore aim:

About the Probiotics Database

Independent & Educational Resource

This is a non-commercial project, and is intended as an informative, educational tool and resource for healthcare professionals, health journalists and those with a particular interest in probiotics.

The probiotic strains included on the database are not limited to those in the OptiBac Probiotics range but have rather been independently identified by our team of nutritional therapists, as the most researched probiotic strains in the world. The strains have been chosen by both quantity of research behind them, but mainly by the quality of the research. By this we refer to the design of the studies, significance of the results, and of course population size studied.


Research on probiotics is a changing landscape with new studies being carried out and new strains being discovered. We aim to update the Probiotic Database accordingly and regularly. If you feel there is anything particularly missing feel free to contact us.

N.B.: Do note that this Database comprises a list of the world’s most extensively researched probiotic strains only, and therefore is not intended to encompass every single species or strain of bacteria within the Lactobacillus, Bifidobacteria & Saccharomyces genera.

Clinical Research

Please note also that we have focused on clinical research rather than in-vitro or animal studies. It’s safe to assume that all strains of probiotic bacteria documented have been thoroughly researched in-vitro for stomach acidity survival, adhesion and repopulation in the gut. If they were not performing in this way, it would be highly unlikely that these strains would have the results they do in the clinical trials detailed in this database.

We hope you find this a helpful resource! If so please share with your friends, link to it from your website and share it on social media. Please note also that this database is best viewed on desktop – so if visiting on mobile, please do bookmark it and come back when at your desk!

Research and consolidation by Joanna Scott-Lutyens BA (hons), DipION, Nutritional Therapist; Kerry Beeson, BSc (Nut.Med) Nutritional Therapist; Megan Crowch BSc (Hons), Dip Naturopathy; and Laura Ryan Dip Nutritional Therapist.

Last updated - 11th May, 2018



  • This information will be very useful.
    During your research did you come across anything specific which correlates obesity and probiotics

  • Response from OptiBac Probiotics

    Dear Julie,

    Thank you for your query, and I'm so pleased that you're finding the Probiotics Database to be a valuable resource.

    The research studies we have listed relate only to the strains we have included in the Database, which comprises a premium selection of strains which we considered to be the most extensively-researched probiotics in the world. We have given an overview of their strengths based on the weight of research that supports their use, and for now, this does not include obesity and weight management. Whilst there may be studies in the field that are looking at the effects of probiotics in weight management, as yet, the research is still in its infancy and very little, if any, research into the effects of probiotics on obesity has been carried out on the specific strains that we have listed in the Database.

    If you are looking to advise clients regarding gut health and weight management, until more evidence on specific strains is available, we would advise focusing on overall gut health and a optimising digestive function.

    With kind regards,


  • I would sincerely like to express my gratitude towards you for assembling probiotic database and providing information which is very helpful.

    Thank you

  • You guys should look into Lactobacillus Fermentum ME-3. It has a few clinical studies on oxidative stress markers, increasing PON1, Glutathione, and even fighting pathogen.

  • Response from OptiBac Probiotics

    Dear John,

    Thank you for your comment and suggestion.

    We're always looking out for interesting and extensively researched strains to add to our ever growing database, so we appreciate your suggestion!

    Thanks again for your comment.

    With best wishes,


  • What an incredible tool on all things probiotic! As a GP in the NHS, I'm disappointed with the lack of access to information about probiotics and the research behind them. Many of my colleagues are unaware that probiotics have seen any clinical trials. Having started my research journey (prompted by a few patients with unrelenting IBS symptoms) I'm very impressed to find this resource, so thank you, and I hope you are able to keep up the great work.

  • Response from OptiBac Probiotics

    Dear Miranda,

    Thank you so much for your feedback. We really appreciate it and we're glad you've found the database useful.

    With best wishes,


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