Oral Drugs That Trigger the Body to Release Its Own Appetite-Suppressing Peptides Produce Weight Loss | Research

The takeaway

Oral drugs activating GPR40 and GPR119 receptors massively increased six natural satiety peptide hormones (up to 8.6x), producing significant weight loss and blood pressure reductions in obese participants.

PYY up 8.63x
Oral GPR40/GPR119 co-agonism produced dramatic increases in multiple satiety peptide hormones, with PYY (appetite-suppressing peptide) rising nearly 9-fold above placebo

What the researchers found

Co-administration of K-757 (GPR40 agonist) and K-833 (GPR119 agonist) in obese subjects produced dramatic increases in multiple gut peptide hormones: GLP-1 up 3.44x, active GLP-1 up 5.06x, PYY up 8.63x, GIP up 1.65x, CCK up 3.06x, and oxyntomodulin up 5.66x compared to placebo. In the 13-week Phase 2a trial (n=155), the combination produced placebo-adjusted weight loss of -2.78% (p<0.001) and blood pressure reductions of -6.9/-5.4 mmHg.

K-757 alone also elevated gut peptides and produced blood pressure reductions (-5.3/-3.2 mmHg), though weight loss was more modest (-1.42%, p=0.076). GI adverse events were more common with active treatment.

Why it matters

Rather than injecting synthetic peptide hormones (like semaglutide or tirzepatide), this approach uses oral drugs to stimulate the body's own production of multiple satiety peptides simultaneously. The massive increases in GLP-1, PYY, oxyntomodulin, and CCK — all natural appetite-suppressing peptides — suggest a fundamentally different strategy for obesity treatment. The blood pressure reductions independent of weight loss hint at metabolic benefits that go beyond appetite suppression.

The numbers in context

n=155 (Phase 2a) · 13 weeks · GLP-1 3.44x · Active GLP-1 5.06x · PYY 8.63x · GIP 1.65x · CCK 3.06x · Oxyntomodulin 5.66x · Weight loss -2.78% · BP -6.9/-5.4 mmHg

How the study worked

Phase 1 study identified optimal dosing for maximal gut hormone secretion. Phase 2a was a randomized, double-blind, parallel-arm, 13-week study in 155 overweight-obese participants without type 2 diabetes, randomized to K-757 alone, K-757+K-833 combination, or placebo (~51-52/arm). Circulating gut peptide levels were measured. Primary outcomes included weight change; blood pressure was an exploratory endpoint.

Who was studied

Overweight-obese adults without type 2 diabetes mellitus (155 participants, Phase 2a)

What this study cannot tell us

The 13-week Phase 2a study is relatively short, and the 2.78% weight loss, while significant, is modest compared to injectable GLP-1 agonists like semaglutide (~15%). GI adverse events were common with active treatment. The drugs are not peptides themselves — they stimulate peptide release — so their effects depend on the body's ability to produce these hormones. Blood pressure was an exploratory endpoint, not a primary outcome. Longer and larger trials are needed.

How to read the evidence

Phase 2a randomized, double-blind, placebo-controlled trial with 155 participants over 13 weeks. This is early-stage clinical evidence — promising but requires larger, longer Phase 2b/3 trials to confirm efficacy and safety.

When this study was published

Published in 2025, this is very recent clinical data representing a novel oral approach to obesity treatment through endogenous peptide hormone stimulation.

The bigger picture

The obesity drug market is dominated by injectable GLP-1 agonists, but many patients prefer oral medications. This approach — stimulating the body's own peptide hormone production via oral GPR40/GPR119 agonists — represents a fundamentally different strategy. By elevating multiple satiety peptides simultaneously (not just GLP-1), it may engage complementary appetite and metabolic pathways. If larger trials show enhanced efficacy, this could become a convenient oral alternative or complement to injectable peptide therapies.

Questions still open

Can the weight loss be enhanced with dose optimization or longer treatment duration to rival injectable GLP-1 agonists?
Does the simultaneous elevation of six gut peptides provide cardiovascular or metabolic benefits beyond what single-peptide therapies achieve?
Will the GI adverse events limit long-term adherence to this oral treatment approach?

Common questions

How is this different from taking semaglutide or tirzepatide?

Semaglutide and tirzepatide are injectable synthetic peptides that mimic GLP-1 (and GIP for tirzepatide). This approach uses oral pills that stimulate your gut cells to release their own natural peptide hormones — not just GLP-1 but also PYY, CCK, oxyntomodulin, and GIP. Instead of replacing one hormone with a synthetic version, it amplifies the body's natural multi-hormone response to food.

Why was the weight loss less than with injectable GLP-1 drugs?

Injectable GLP-1 agonists like semaglutide maintain continuous high levels of a single peptide, producing ~15% weight loss over a year. This oral approach relies on the body's own peptide production, which may not achieve the same sustained high levels. However, the multi-peptide approach may offer unique metabolic benefits (like the blood pressure reduction) that complement weight loss, and dose optimization may improve results in future trials.

Read the original research

Combined agonism of nutrient receptors GPR40 and GPR119 with K-757 and K-833 results in weight loss and blood pressure reductions in obese subjects without type 2 diabetes mellitus.

Diabetes, obesity & metabolism, 27(12), 7198-7209

View on PubMed ↗Publisher’s paper ↗

Citation

Crutchlow, Michael; Liu, Jiajun; Romero, Christopher; Watkins, Elaine; Zhang, Harry; Arreglado, Anna; Vance, Annemarie; Boisvert, Daniel; Terracina, Giuseppe; Chan, Bryan; Consolati, Matt J; Poterewicz, Gregory; Talaty, Jennifer E; Lauring, Brett. (2025). Combined agonism of nutrient receptors GPR40 and GPR119 with K-757 and K-833 results in weight loss and blood pressure reductions in obese subjects without type 2 diabetes mellitus.. Diabetes, obesity & metabolism, 27(12), 7198-7209. https://doi.org/10.1111/dom.70120