May 12, 2026

expert reaction to an RCT on the use of pasteurized Akkermansia muciniphila MucT for weight loss maintenance after an 8-week low-energy diet

A randomised controlled trial published in Nature Medicine looks at pasteurized Akkermansia muciniphila MucT for weight loss maintenance in people with overweight and obesity. 

Comments from our friends at the Spanish SMC:

Francisco Jesús Gómez Delgado, coordinator of the Vascular Risk Unit and head of the Department of Internal Medicine at Jaén University Hospital, associate professor of Medicine at the University of Jaén and member of the Diabetes, Obesity and Nutrition Group of the Spanish Society of Internal Medicine, said:

Is it a high-quality study?

“This study is a randomised, placebo-controlled trial, so we can affirm its methodological robustness for a clinical proof of concept. Furthermore, it incorporates biomarkers and mechanisms of interest in the understanding of metabolic health, such as the gut microbiota, adipose tissue, and lipid and glucose metabolism.”

What are its limitations?

“On the other hand, its sample size is small, the follow-up period is short, and the demonstrated effect on body weight is limited. Furthermore, it does not include other active comparators or biological models that would allow the observed benefit to be confirmed or clarified more precisely.”

What are its implications and how does it fit with existing evidence?

“In this regard, it clearly supports the hypothesis and the role played by our gut microbiota, depending on its profile, in phenomena such as inflammation, dyslipidaemia or diabetes. Likewise, this study identifies the gut microbiota as a genuine therapeutic target in the management of obesity. Furthermore, it is proposed as a complementary tool to supplement pharmacological, nutritional and behavioural strategies, which makes it an interesting option.”

José Pablo Miramontes González, a consultant in internal medicine at the Department of Internal Medicine at Río Hortega Hospital (Valladolid), said:

“The trial with pasteurised Akkermansia muciniphila MucT has a sound design: randomised, double-blind and placebo-controlled, with an initial low-calorie diet phase followed by a 24-week maintenance phase. The primary outcome is positive: participants treated with Akkermansia regained less weight than those in the placebo group, with a difference of approximately 2 kg during the maintenance phase, and the effect appeared to be greater in subjects with lower baseline abundance of Akkermansia. Furthermore, the study provides interesting mechanistic data on insulin sensitivity, faecal energy excretion, microbiota and gene expression in adipose tissue, making it biologically plausible rather than merely descriptive. That said, caution is warranted: it is a small, short-term study conducted in a highly selected population and without comparison to current anti-obesity drug treatments. The magnitude of the effect is modest and does not allow us to conclude that this intervention is an alternative to incretin agonists, but rather a possible complementary strategy.

“Mechanistic questions also remain, as there was no active bacterial comparator or modified strains to allow the effect to be attributed with certainty to specific components of Akkermansia. Therefore, in my view, the study is promising, but it should be interpreted as a clinical and metabolic proof of concept, not as definitive evidence to change clinical practice”.

‘Pasteurized Akkermansia muciniphila MucT for weight loss maintenance in people with overweight and obesity: a controlled randomized trial’ by Sarah Mount et al. was published in Nature Medicine at 23:00 UK time on Tuesday the 12th of May 2026. 

DOI: https://doi.org/10.1038/s41591-026-04394-7

Declared interests

Francisco Jesús Gómez Delgado:

• Speaker: Ferrer, Amgen, Sanofi, AstraZeneca, Boehringer Ingelheim–Lilly, Janssen,       Novo Nordisk, Daiichi Sankyo, Novartis, Rovi and Vifor.
• Advisory board: Amgen and Sanofi.
• Conference invitations: Ferrer, Amgen, Sanofi, AstraZeneca, Boehringer Ingelheim–Lilly, Janssen, Novo Nordisk, Daiichi Sankyo and Rovi.
• Clinical trial investigator: Ferrer, Amgen, Sanofi, Janssen, Novo Nordisk, Daiichi       Sankyo, Novartis, Ionis Pharmaceuticals and Boehringer Ingelheim–Lilly.

José Pablo Miramontes González: He has not responded regarding any conflicts of interest