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 Probiotics Database accordingly and regularly. If you feel there is anything particularly missing feel free to let us know in the comments.

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) Physiology, Herbal Medicine Diploma (IRH practicing member); Laura Ryan, BSc (Hons) Psychology, DipCNM NT, mBANT, CNHC; and Dr Kate Stephens, PhD | Food and Microbial Sciences; Gut Microbiology (University of Reading), BSc (Hons) Medical Microbiology