A New Fat-Blocking Drug Combined With Tirzepatide or Semaglutide Produced Greater Weight Loss in Obese Mice | Research

The takeaway

The MOGAT2 inhibitor VB-87531 synergized with both tirzepatide and semaglutide to produce greater weight loss, reduced food intake, and improved metabolic markers compared to any treatment alone in obese mice.

IC50 = 17.4 nM
VB-87531's high potency against MOGAT2, combined with dose-dependent synergy with tirzepatide, positions it as a promising combination partner for peptide-based obesity treatments

What the researchers found

VB-87531 is a potent inhibitor of human MOGAT2 (IC50 = 17.4 nM) that, when administered to diet-induced obese mice:

Alone: reduced body weight, food intake, blood cholesterol, and glucose levels with no liver toxicity

Combined with tirzepatide: enhanced weight loss and reduced food intake vs. VB-87531 alone; dose-dependent modulation of both outcomes

Combined with semaglutide: similarly enhanced weight loss and reduced food intake vs. VB-87531 alone

Both combinations significantly lowered insulin and leptin levels while increasing FGF21 (a metabolic hormone linked to fat burning) and PYY (a satiety peptide). The synergistic effects suggest complementary mechanisms: VB-87531 blocks dietary fat absorption while GLP-1/GIP agonists suppress appetite and improve metabolic signaling.

Why it matters

Despite the remarkable success of GLP-1 drugs, many patients don't lose enough weight to resolve their obesity-related health problems. Finding drugs that synergize with existing peptide therapies could push weight loss to levels approaching bariatric surgery without the need for an operation. Targeting fat absorption (MOGAT2) complements the appetite suppression of GLP-1 drugs — attacking obesity from two different angles simultaneously.

How the study worked

Diet-induced obese (DIO) mice fed a high-fat diet were treated with VB-87531 alone, tirzepatide alone, semaglutide alone, or combinations of VB-87531 with either peptide drug. Outcomes included body weight changes, food intake, blood cholesterol, glucose, insulin, leptin, FGF21, and PYY levels. Liver toxicity was assessed. Dose-dependent effects were evaluated for the VB-87531/tirzepatide combination.

What this study cannot tell us

This is a mouse study using diet-induced obesity, which may not fully predict human responses. The specific degree of additional weight loss from combination therapy vs. monotherapy is not quantified in the abstract. VB-87531 has not been tested in humans (unlike the related compound BMS-963272). Long-term safety of blocking fat absorption chronically is unknown — potential concerns include fat-soluble vitamin deficiency and gastrointestinal side effects. The dose-dependency was only assessed with tirzepatide, not semaglutide.

How to read the evidence

This is a preclinical study in diet-induced obese mice showing proof of concept for combination therapy. The multiple endpoints and dose-response data add rigor, but no human safety or efficacy data exist for VB-87531. A related MOGAT2 inhibitor (BMS-963272) has shown weight loss in healthy obese humans, providing class-level validation.

When this study was published

Published in 2025, this study is at the cutting edge of combination obesity therapy research, an area of intense pharmaceutical development.

The bigger picture

The obesity drug field is rapidly moving toward combination therapy — much like hypertension treatment, where multiple drugs with different mechanisms are used together. This study adds MOGAT2 inhibition as a potential combination partner for GLP-1/GIP agonists. Other emerging combinations include amylin analogs (cagrilintide + semaglutide), GLP-1/GIP/glucagon triple agonists, and leptin sensitizers. The race is on to find combinations that achieve surgical-level weight loss (25-35%) with pills and injections.

Questions still open

Could a MOGAT2 inhibitor combined with tirzepatide achieve weight loss comparable to bariatric surgery in humans?
Would blocking fat absorption with VB-87531 cause gastrointestinal side effects similar to orlistat, or does the MOGAT2 mechanism avoid this?
What is the optimal dose ratio between VB-87531 and GLP-1/GIP agonists for maximum synergy with minimum side effects?

Common questions

How does VB-87531 work differently from GLP-1 drugs?

GLP-1 drugs like semaglutide primarily suppress appetite through brain signaling, while VB-87531 blocks MOGAT2, an enzyme needed to reassemble dietary fats in the intestine for transport to the liver. By blocking fat absorption at the gut level, VB-87531 reduces caloric intake from fat regardless of appetite. Together, the two approaches attack obesity from different angles — less hunger from the brain AND less fat absorbed from food — which is why they synergize.

Could this lead to a pill that boosts the effects of Ozempic or Mounjaro?

That's exactly the idea. Since VB-87531 is a small molecule taken orally, it could potentially be prescribed as a pill alongside injectable GLP-1/GIP drugs to enhance weight loss. A similar MOGAT2 inhibitor (BMS-963272) has already shown weight loss in humans, suggesting this approach is feasible. However, VB-87531 specifically still needs human safety testing and clinical trials before it could become available.

Read the original research

The inhibitor VB-87531 synergizes with tirzepatide and semaglutide for greater weight loss in DIO mice.

Biochemical and biophysical research communications, 778, 152360

View on PubMed ↗Publisher’s paper ↗

Citation

Corbalan, J Jose; Petronella, Brenda A; Huang, Chia-Yu; Beasley, James R; Merritt, James R; Mugrage, Benjamin B; Nickels, Joseph T. (2025). The inhibitor VB-87531 synergizes with tirzepatide and semaglutide for greater weight loss in DIO mice.. Biochemical and biophysical research communications, 778, 152360. https://doi.org/10.1016/j.bbrc.2025.152360