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Metformin and gut microbiota: their interactions and their impact on diabetes

  • Natalia G. VallianouEmail author
  • Theodora Stratigou
  • Stylianos Tsagarakis
Review Article


The ratio of human to bacterial cells in the human body (microbiota) is around 1:1. As a result of co-evolution of the host mucosal immune system and the microbiota, both have developed multiple mechanisms to maintain homeostasis. However, dissociations between the composition of the gut microbiota and the human host may play a crucial role in the development of type 2 diabetes. Metformin, the most frequently administered medication to treat patients with type 2 diabetes, has only recently been suggested to alter gut microbiota composition through the increase in mucin-degrading Akkermansia muciniphila, as well as several SCFA-producing (short-chain fatty acid) microbiota. The gut microbiota of participants on metformin has exerted alterations in gut metabolomics with increased ability to produce butyrate and propionate, substances involved in glucose homeostasis. Thus, metformin appears to affect the microbiome, and an individual’s metformin tolerance or intolerance may be influenced by their microbiome. In this review, we will focus on the effects of metformin in gut microbiota among patients with T2DM.


Metformin Microbiota Microbiome Metabolomics Diabetes 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Human and animal rights and informed consent

This article does not contain any studies with human participants performed by any of the authors.


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Copyright information

© Hellenic Endocrine Society 2019

Authors and Affiliations

  1. 1.Department of Endocrinology, Diabetes and MetabolismEvangelismos General HospitalAthensGreece

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