LEAP2 Combined With Semaglutide Produces Superior Weight Loss in Preclinical Obesity Models

Bottom line: Blocking ghrelin with long-acting LEAP2 while simultaneously activating GLP-1 receptors with semaglutide may represent the next frontier in combination peptide therapy for obesity.

LEAP2 (liver-expressed antimicrobial peptide 2) is a 40-amino-acid peptide originally identified for its antimicrobial properties but now recognized as the endogenous antagonist of the growth hormone secretagogue receptor (GHSR1a) — better known as the ghrelin receptor. By blocking ghrelin's orexigenic (appetite-stimulating) signal, LEAP2 reduces food intake through a mechanism entirely distinct from GLP-1 receptor agonists like semaglutide.

Study Design

Published on PubMed in 2026, this preclinical study evaluated a long-acting LEAP2 analog (LA-LEAP2) alone and in combination with semaglutide in diet-induced obese mice.¹ The investigators measured body weight, food intake, energy expenditure, and metabolic parameters across multiple experimental protocols.

Key Findings

• LA-LEAP2 monotherapy significantly reduced body weight in obese mice, driven by decreased energy intake with preserved energy expenditure¹
• Combination with semaglutide: In some experiments, the LA-LEAP2 + semaglutide combination produced superior weight reduction compared with semaglutide alone, though this was not uniformly observed across all experimental conditions
• Metabolic preservation: Unlike caloric restriction, LEAP2-mediated weight loss did not reduce energy expenditure — a key advantage for sustained weight management
• The combination did not produce additive adverse effects

Why Combination Matters

A major limitation of current GLP-1-based monotherapy is the weight-loss plateau and weight regain after discontinuation. The ghrelin system represents a compensatory pathway: as patients lose weight on semaglutide or tirzepatide, ghrelin levels rise, driving hunger and potentially limiting further weight loss.²

Blocking this compensatory ghrelin surge with LEAP2 while maintaining GLP-1 agonism could theoretically:

• Push past the monotherapy weight-loss ceiling
• Reduce hunger-driven non-compliance
• Preserve metabolic rate during weight loss

Translation to Humans

A recent human study demonstrated that exogenous LEAP2 reduces ad libitum food intake in men with obesity,³ and a registered clinical trial (NCT07171723) is evaluating LEAP2's physiological effects in patients already receiving semaglutide — a key step toward validating the combination approach in humans.

Clinical implication: This preclinical work supports the rationale for dual ghrelin-GLP-1 pathway targeting and should accelerate clinical development of LEAP2 analogs as add-on therapy to existing incretin-based obesity treatments.

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References

1. Sustained weight loss with combined LEAP2 and semaglutide in obese mice. PubMed. 2026. PMID: 40590720.
2. Müller TD, et al. Ghrelin. Mol Metab. 2015;4(6):437-460.
3. LEAP2 reduces ad libitum food intake and attenuates postprandial glucose excursions in men with obesity. Diabetes. 2026. PMID: 41911360.