LEAP-2 is a liver-produced peptide that naturally blocks the ghrelin receptor, making it ghrelin's built-in rival in appetite control and a potential new target for obesity treatment.
First endogenous ghrelin receptor antagonist discoveredLEAP-2 is the body's own built-in ghrelin blocker — a liver-produced peptide that naturally counteracts the hunger hormone, creating a yin-yang balance in appetite control.
What the researchers found
LEAP-2 (liver-expressed antimicrobial peptide 2) is a recently discovered endogenous antagonist of the ghrelin receptor (GHSR1a). It works as a noncompetitive allosteric blocker — meaning it doesn't compete with ghrelin directly but instead changes the receptor's shape to prevent ghrelin from activating it. In lab experiments, LEAP-2 blocked ghrelin's ability to trigger calcium signaling, and in animal studies, it impaired ghrelin's metabolic effects.
The review presents LEAP-2 as ghrelin's natural counterbalance in energy metabolism: where ghrelin drives hunger and promotes fat storage, LEAP-2 opposes these effects. This makes LEAP-2 a promising therapeutic target for obesity and metabolic diseases involving ghrelin system dysregulation.
Why it matters
For over 20 years, ghrelin was the only known hormone that stimulates appetite. The discovery of LEAP-2 as its natural antagonist fundamentally changes our understanding of hunger regulation — it's not just about ghrelin levels, but the balance between ghrelin and LEAP-2. This opens an entirely new therapeutic avenue: rather than blocking ghrelin directly, boosting LEAP-2 could suppress appetite through the body's own counterregulatory system.
The numbers in context
LEAP-2 = endogenous GHSR1a antagonist · Noncompetitive allosteric mechanism · Blocks ghrelin-induced Ca²⁺ release in vitro · In vivo metabolic effects confirmed
How the study worked
Narrative review synthesizing recent discoveries about LEAP-2's role as a ghrelin receptor antagonist, covering molecular pharmacology (in vitro receptor studies), in vivo metabolic effects, and therapeutic implications for obesity and metabolic disease.
Who was studied
Review of in vitro and animal studies (no human clinical data)
What this study cannot tell us
Narrative review without systematic methodology. LEAP-2 research was very early-stage when this was published. Most evidence was from in vitro receptor studies and animal models. Human clinical data on LEAP-2 modulation was absent. The therapeutic potential discussed was largely speculative at time of publication.
How to read the evidence
Rated low-moderate: published in a high-impact pharmacology journal and based on emerging in vitro and in vivo evidence, but the field was very early-stage. No human clinical data was available at time of publication.
When this study was published
Published in 2018, shortly after LEAP-2's role as a ghrelin antagonist was first discovered. Subsequent research has significantly expanded our understanding of LEAP-2 in human metabolism, so this should be read as an early-stage overview.
The bigger picture
The ghrelin system was long thought to be a one-way signal — ghrelin goes up, you get hungry. LEAP-2's discovery adds a counterweight, creating a push-pull system more like insulin/glucagon for blood sugar. This has major implications for obesity research: instead of just suppressing appetite with GLP-1 drugs, future treatments might restore the ghrelin-LEAP-2 balance. It also helps explain why some obese individuals have low ghrelin but still overeat — their LEAP-2 levels may be dysregulated too.
Questions still open
- Can synthetic LEAP-2 or LEAP-2 mimetics reduce food intake and body weight in human clinical trials?
- How do LEAP-2 levels change with obesity, weight loss, and bariatric surgery in humans?
- Could combining LEAP-2 enhancement with GLP-1 agonists produce additive anti-obesity effects?
Common questions
What is LEAP-2 and how does it relate to hunger?
Could LEAP-2 be used as a weight loss drug?
Read the original research
Ghrelin and LEAP-2: Rivals in Energy Metabolism.
Trends in pharmacological sciences, 39(8), 685-694
Citation
Al-Massadi, Omar; Müller, Timo; Tschöp, Matthias; Diéguez, Carlos; Nogueiras, Ruben. (2018). Ghrelin and LEAP-2: Rivals in Energy Metabolism.. Trends in pharmacological sciences, 39(8), 685-694. https://doi.org/10.1016/j.tips.2018.06.004