Future Obesity Therapies: How Gut Hormone Combinations Could Match Bariatric Surgery Weight Loss | Research

The takeaway

Dual and triple gut hormone agonists combining GLP-1 with GIP, glucagon, and amylin are approaching the weight loss achieved by bariatric surgery, marking a new era in obesity pharmacotherapy.

Approaching surgical-level weight loss
Tirzepatide and emerging triple gut hormone agonists are producing weight loss that rivals bariatric surgery, transforming obesity from a primarily surgical disease to a medical one

What the researchers found

Tirzepatide (GLP-1/GIP dual agonist) marks a new era where pharmacotherapy approaches bariatric surgery-level weight loss. Multiple gut hormone combination strategies are under investigation: GLP-1 + GIP (tirzepatide, already approved), GLP-1 + glucagon (for enhanced energy expenditure and fat metabolism), GLP-1 + GIP + glucagon triple agonists, and amylin analogs. Each additional hormone target complements GLP-1's appetite-suppressing effects through different mechanisms — GIP enhances insulin and may directly affect fat tissue, glucagon increases energy expenditure, and amylin slows gastric emptying and promotes satiety.

Why it matters

For decades, the only obesity treatment producing dramatic, sustained weight loss was surgery. The emergence of gut hormone combination drugs that can approach surgical outcomes represents a paradigm shift — potentially making effective obesity treatment available to hundreds of millions of people worldwide who would never qualify for or accept surgery. This review provides a roadmap of what's coming in the next few years.

How the study worked

Narrative review published in Clinical Medicine (Royal College of Physicians) covering emerging obesity treatments, with focus on gut hormone combination pharmacotherapy and the multimodal management approach.

What this study cannot tell us

This is a 2023 review, and the gut hormone drug pipeline is evolving rapidly — some drugs discussed may have advanced, failed, or been superseded by newer candidates. The comparison to bariatric surgery outcomes is based on different trial populations and time frames. Long-term durability of drug-induced weight loss (versus surgery's proven decades-long maintenance) remains uncertain. Cost and access barriers to these expensive medications are not fully addressed.

How to read the evidence

This is a narrative review synthesizing clinical trial data for approved and investigational obesity drugs. The evidence for approved drugs (tirzepatide, semaglutide) is based on large Phase III trials, while pipeline drugs have Phase II/III data of varying maturity.

When this study was published

Published in 2023 in Clinical Medicine, this review captures the obesity drug landscape at a pivotal moment. Since publication, several pipeline drugs discussed have advanced further in clinical development.

The bigger picture

The gut hormone-based obesity drug revolution is the biggest advance in metabolic medicine in a generation. What started with GLP-1 monoagonists has rapidly evolved into multi-hormone strategies that exploit the gut's full appetite-regulatory toolkit. The concept of 'medical bariatrics' — achieving surgery-like outcomes with drugs — is becoming reality. Combined with the recognition that obesity requires long-term, multimodal management (not just a single intervention), this review captures a transformative moment in obesity medicine.

Questions still open

Will triple agonists consistently surpass tirzepatide's weight loss, and can their side effect profiles be managed?
How durable is gut hormone drug-induced weight loss over 5-10 years compared to bariatric surgery?
What combination of gut hormone drugs and lifestyle interventions will produce the best long-term metabolic outcomes?

Common questions

Could drugs ever replace bariatric surgery for weight loss?

This review suggests we're getting close. Tirzepatide, which targets two gut hormones simultaneously, already produces weight loss approaching what surgery achieves. Even more powerful combinations are in development — triple agonists targeting three hormones at once. While surgery still has advantages for some patients (especially immediate, dramatic results), the gap between drug and surgical outcomes is narrowing rapidly.

Why combine multiple gut hormones instead of using just one?

Each gut hormone controls appetite and metabolism through different mechanisms. GLP-1 suppresses appetite and slows stomach emptying. GIP enhances insulin and may directly affect fat tissue. Glucagon increases energy expenditure and fat burning. Amylin promotes fullness and slows digestion. By combining signals from multiple hormones, dual and triple agonists attack obesity from several angles simultaneously, producing greater weight loss than any single hormone can achieve alone.

Read the original research

Future therapies for obesity.

Clinical medicine (London, England), 23(4), 337-346

View on PubMed ↗Publisher’s paper ↗

Citation

Melson, Eka; Miras, Alexander Dimitri; Papamargaritis, Dimitris. (2023). Future therapies for obesity.. Clinical medicine (London, England), 23(4), 337-346. https://doi.org/10.7861/clinmed.2023-0144