Pasteurized Akkermansia muciniphila Supplement Slows Weight Regain After Diet-Induced Loss, Phase 2 Trial Shows
Key Insights
A randomized, placebo-controlled trial of 90 overweight and obese adults found that daily pasteurized Akkermansia muciniphila supplementation reduced weight regain after an 8-week low-calorie diet.
Participants taking the gut bacterium regained an average of 1.2 kg (2.6 lbs) over 24 weeks compared to 3.2 kg (7.1 lbs) in the placebo group, a statistically significant difference.
Improvements in cardiometabolic markers, including insulin sensitivity, were also observed, with greater benefits seen in those with lower baseline Akkermansia levels.
A specific gut bacterium may offer a new strategy for one of the most persistent challenges in obesity (search) management: keeping weight off after losing it. New research published in Nature Medicine demonstrates that daily supplementation with pasteurized Akkermansia muciniphila significantly reduced weight regain in overweight and obese adults following an initial diet-induced weight loss phase.
The randomized, placebo-controlled trial enrolled 90 overweight and obese adults from the Netherlands. Participants first completed an eight-week, low-energy diet consisting of meal replacement soups and shakes totaling 800–900 calories per day. Those who lost at least 8% of their body weight then entered a 24-week weight-maintenance phase, where they were randomly assigned to receive either daily supplements containing pasteurized Akkermansia muciniphila or a placebo. Throughout the maintenance period, participants were instructed to follow a healthy diet aligned with Dutch dietary guidelines but were told they could eat as much or as little as they wanted.
Significant Reduction in Weight Regain
By the end of the 24-week maintenance phase, the group receiving Akkermansia muciniphila regained significantly less weight than the placebo group. On average, those taking the supplement regained approximately 1.2 kg (2.6 pounds), compared with 3.2 kg (7.1 pounds) in the placebo group — a statistically significant difference. This suggests that supplementation slowed, but did not fully prevent, weight regain after initial weight loss.
The researchers also observed improvements in certain cardiometabolic markers, including enhanced insulin sensitivity in the supplemented group, indicating that the body was responding to insulin more effectively.
Mechanism and Pasteurization Rationale
Notably, the study did not use live Akkermansia muciniphila bacteria. Instead, a pasteurized version — heat-treated so the bacteria were no longer alive — was administered. This approach may appear counterintuitive, but previous research suggests that some of the beneficial effects of probiotics, including A. muciniphila, may derive from components of the bacterial cell rather than from live microbes. Pasteurization may even enhance the microbe's effects.
Dr. Peter Balazs, a hormone and weight loss specialist practicing in New York and New Jersey who was not involved in the research, explained that pasteurized Akkermansia works through "components of the bacteria, particularly a protein called Amuc_1100." He added: "This protein helps strengthen the gut barrier, reduce low-grade inflammation and support healthy metabolic function. After weight loss, the body naturally tries to regain fat, but Akkermansia appears to help quiet some of those biological signals, making it easier to maintain results over time."
The Role of Baseline Microbiome Composition
The efficacy of the treatment appears to depend on a person's existing gut microbiome. Participants with lower baseline gut levels of Akkermansia appeared to show greater cardiometabolic improvements, highlighting a broader challenge in microbiome science: people's gut microbiomes vary enormously, and treatments that work well for one person may have little effect in another.
Limitations and Caveats
The study authors acknowledged several limitations. The trial's short duration and small sample size may not be sufficient to prove long-term benefits. Another limitation is that participants ate whatever they wanted during the maintenance phase rather than following a standardized diet. Additionally, several authors declared links to the company producing the supplement used in the trial. While such collaborations are common in translational research, independent studies will be important to confirm and build on these findings.
No serious adverse events were reported during the study.
Dr. Balazs called the trial "well-designed" and noted: "The finding that a single gut microbe, pasteurized Akkermansia, significantly reduced weight regain is particularly compelling. Most probiotics have demonstrated far less efficacy, making these results especially noteworthy." He cautioned, however, that Akkermansia is not a "miracle pill."
Broader Context in Microbiome Research
Akkermansia muciniphila is an abundant species in the human gut microbiome that lives in the mucus layer lining the gut. It feeds on mucin — the proteins and sugars that make up this mucus — and is thought to play a role in maintaining the gut's protective barrier while also influencing metabolism. Higher levels of Akkermansia muciniphila have been linked with better metabolic health, including improved blood sugar control, while lower levels are observed in people with obesity (search) and type 2 diabetes (search).
The microbiome is influenced by diet, exercise, sleep, medications, and many other factors. As a result, microbiome-based therapies are unlikely to be simple, one-size-fits-all solutions. Research suggests it may even be possible to support and increase Akkermansia muciniphila without supplementation through diets rich in fiber, particularly prebiotic fibers found in foods such as onions, garlic, leeks, asparagus, and whole grains, as well as plant foods high in polyphenols like berries and grapes.