GLP-1 Agonists Beyond Semaglutide: The Expanding Research Landscape

The GLP-1 Revolution in Context

Semaglutide (Ozempic, Wegovy) has become the most publicly visible peptide in history, but it's just one compound in a rapidly expanding class. The GLP-1 receptor agonist landscape is evolving quickly, with multi-target peptides, oral formulations, and novel mechanisms in various stages of development.

For researchers, understanding this broader landscape provides context for where the field is heading and what opportunities exist beyond the semaglutide spotlight.

Tirzepatide: The Dual Agonist

Tirzepatide (marketed as Mounjaro and Zepbound) represents the most significant advancement in incretin therapy since semaglutide. Unlike semaglutide, which targets only the GLP-1 receptor, tirzepatide is a dual GIP/GLP-1 receptor agonist.

GIP (glucose-dependent insulinotropic polypeptide) was historically considered a less interesting target than GLP-1. Tirzepatide changed that perception. The SURMOUNT trials demonstrated weight loss of up to 22.5% of body weight — surpassing semaglutide's approximately 15-17%.

The dual agonist approach appears to provide additive or synergistic effects: GLP-1 activation suppresses appetite and slows gastric emptying, while GIP activation enhances insulin sensitivity and may influence fat metabolism through mechanisms not yet fully understood.

Tirzepatide is now Health Canada-approved and available in Canada, though supply constraints similar to semaglutide have been reported.

Survodutide and Triple Agonists

The logical extension of dual agonism is triple agonism. Survodutide (a GLP-1/glucagon dual agonist) and retatrutide (a GLP-1/GIP/glucagon triple agonist) are in clinical development.

Retatrutide has generated particular excitement. Phase II data showed up to 24.2% body weight reduction at 48 weeks — the highest ever reported for a weight management medication. The addition of glucagon receptor agonism appears to increase energy expenditure (glucagon promotes thermogenesis and fat oxidation) while the GLP-1 and GIP components handle appetite suppression and glucose homeostasis.

These multi-target approaches represent a fundamental shift in metabolic peptide research: rather than maximising a single pathway, researchers are combining complementary mechanisms.

Oral GLP-1 Agonists

One of the most practically significant developments is the advancement of oral GLP-1 formulations. Semaglutide already exists in oral form (Rybelsus), but its bioavailability is low (approximately 1%) and it requires specific administration conditions (empty stomach, limited water, 30-minute fasting window).

Next-generation oral formulations aim to improve bioavailability and simplify dosing. Several approaches are in development: - SNAC-enhanced formulations (the technology behind Rybelsus) with improved absorption enhancers - Capsule-based injection devices that physically inject the peptide into the stomach lining - Nanoparticle delivery systems that protect the peptide from gastric degradation

If oral bioavailability can be meaningfully improved, it would remove the injection barrier that currently limits patient adherence.

Beyond Weight: Expanding Therapeutic Applications

The GLP-1 agonist story is expanding far beyond diabetes and weight management. Active research areas include:

• Cardiovascular protection: The SELECT trial demonstrated that semaglutide reduced major adverse cardiovascular events by 20% independent of weight loss. This has opened an entirely new therapeutic category.
• MASH/NASH: Non-alcoholic steatohepatitis (liver disease) is showing promising response to GLP-1 agonists in clinical trials.
• Neurodegenerative diseases: GLP-1 receptors are present in the brain. Early clinical data suggests potential benefits in Alzheimer's and Parkinson's disease — though this research is in early stages.
• Addiction: Intriguing preclinical and observational data suggests GLP-1 agonists may reduce addictive behaviours, including alcohol consumption. Clinical trials are underway.
• Kidney disease: Semaglutide is being studied for chronic kidney disease outcomes.

The Canadian Research Context

For Canadian researchers, the GLP-1 landscape presents both opportunities and challenges. Pharmaceutical-grade GLP-1 agonists (semaglutide, tirzepatide) are available by prescription but supply-constrained and expensive. Research-grade GLP-1 peptides are available from chemical suppliers but lack the formulation consistency and quality assurance of pharmaceutical products.

The gap between pharmaceutical GLP-1 products and research-grade alternatives is particularly wide for this class because the pharmaceutical formulations include specific excipients and delivery technologies that significantly affect pharmacokinetics. A research-grade semaglutide powder is a very different product from a prefilled Ozempic pen.

What to Watch

The next 12-24 months will likely see: - Phase III results from triple agonist trials (retatrutide) - Expanded cardiovascular and neurological indication approvals - Improved oral formulations approaching market - Growing body of long-term safety data as millions of patients pass the 3-5 year usage mark

The GLP-1 agonist field is the most active area of peptide pharmacology in decades, and its implications extend far beyond weight management.

For our detailed monograph on semaglutide specifically, see the full semaglutide guide.