Every compound discussed below is supplied strictly as a laboratory research material. Several are investigational and not approved for human use in any territory. This article is written for qualified researchers surveying the field and is not medical advice. Trial figures are cited to characterise the science, not to imply any human outcome.
How the field got here: mono → dual → triple
The organising idea behind modern metabolic peptides is the incretin system — the gut hormones that shape insulin secretion, appetite and energy balance. The first generation of research compounds engaged a single receptor: GLP-1. The insight that has driven everything since is that hitting more than one receptor can be additive or even synergistic. Add GIP and you get a dual agonist; add glucagon and you recruit a pathway that raises energy expenditure directly. Push to all three and you have a triple agonist. Running alongside this is a separate lever entirely — amylin — which is now being paired with GLP-1 compounds to compound the effect from a different direction.
That progression is the through-line of the 2026 landscape, and it maps neatly onto the headline trial numbers: each added target has, broadly, moved the reported effect further. If you want the mechanistic detail behind these receptor classes, our explainer on GLP-1 vs GIP vs glucagon agonists breaks down what each receptor actually does.
The 2026 map at a glance
Before the individual profiles, here is the field in one table — compound, the receptors it targets, and the headline research number most associated with it.
| Compound | Class | Receptor targets | Headline number |
|---|---|---|---|
| Semaglutide | Single agonist | GLP-1 | ~15% weight reduction |
| Tirzepatide | Dual agonist | GIP + GLP-1 | ~22.5% weight reduction |
| Mazdutide | Dual agonist | GLP-1 + glucagon | ~14% weight reduction |
| Survodutide | Dual agonist | GLP-1 + glucagon | MASH breakthrough designation |
| Retatrutide | Triple agonist | GIP + GLP-1 + glucagon | ~24.2% weight reduction |
| Cagrilintide | Amylin analogue | Amylin (± GLP-1 as CagriSema) | CagriSema combination data |
Single agonists: the GLP-1 foundation
Semaglutide (GLP-1)
Semaglutide is the reference point for the entire field — the compound every newer molecule is measured against. As a pure GLP-1 receptor agonist, it works through a single, well-characterised pathway, and in research it is associated with a headline of around 15% body-weight reduction. Its long half-life made once-weekly research protocols practical and set the template that the dual and triple agonists later built on. For many labs it remains the natural baseline in a comparison arm. Live pricing and strengths sit on our Semaglutide UK page.
Dual agonists: adding a second target
Tirzepatide (GIP + GLP-1)
Tirzepatide was the compound that proved the dual-agonist thesis. By engaging GIP alongside GLP-1, it pushed the headline research figure to roughly 22.5% — a clear step beyond single-agonist GLP-1. It is the most extensively studied dual agonist and, for now, the benchmark that the glucagon-recruiting duals and the triple agonist are compared against. See strengths and pricing on our Tirzepatide UK page.
Mazdutide (GLP-1 + glucagon)
Mazdutide takes the other dual route: GLP-1 plus glucagon. Rather than adding GIP, it recruits the glucagon receptor, which is associated with increased energy expenditure and effects on hepatic metabolism. Research is associated with a headline around 14%, and much of the interest sits in the glucagon arm's metabolic profile rather than weight number alone. It represents the "GLP-1/glucagon" branch of the dual family in the 2026 map. Details on our Mazdutide UK page.
Survodutide (GLP-1 + glucagon)
Survodutide is the other major GLP-1/glucagon dual, and it is notable less for a single weight figure than for where the glucagon pathway points: liver disease. Survodutide received a breakthrough designation in MASH (metabolic dysfunction-associated steatohepatitis), making it one of the most closely watched compounds for researchers interested in hepatic endpoints rather than body weight alone. It is a good illustration that "beyond GLP-1" increasingly means beyond weight as the primary question. See our Survodutide UK page.
Triple agonists: hitting all three
Retatrutide (GIP + GLP-1 + glucagon)
Retatrutide (LY3437943) is the current frontier of the incretin class: the only triple agonist targeting GIP, GLP-1 and glucagon together. In Phase 2 research it is associated with roughly 24.2% body-weight reduction — the largest reported effect in the class — and notably the curve had not plateaued when the study concluded. Retatrutide is the clearest proof of the mono → dual → triple thesis, and it is the most in-demand research peptide in the UK as a result. Strengths and live pricing on our Retatrutide UK page.
The rough progression — ~15% (GLP-1) → ~22.5% (GIP/GLP-1) → ~24.2% (triple) — is not a straight line, and trial designs differ, so cross-trial comparison is imperfect. But the direction is consistent: each additional receptor tends to recruit a distinct mechanism (appetite, insulin dynamics, energy expenditure), and combining them has generally moved the reported effect further.
The amylin track: a parallel lever
Cagrilintide (amylin) & CagriSema
Not everything interesting in 2026 is an incretin agonist. Cagrilintide is a long-acting amylin analogue — a different hormone system that influences satiety and gastric emptying independently of the GLP-1/GIP/glucagon axis. On its own it is a research compound in its own right; paired with semaglutide as CagriSema, it becomes a combination approach that stacks amylin on top of GLP-1. This dual-mechanism-from-two-systems strategy is where a lot of the field's forward attention now sits, and it hints at how the next generation may be built — not just more incretin receptors, but incretin plus amylin. See our Cagrilintide UK page.
Where the field is heading
Three directions are visible in the 2026 map. First, more targets: the triple agonist showed that stacking receptors keeps paying off, and combinations that pair incretin agonists with amylin (as in CagriSema) extend that logic across hormone systems. Second, beyond weight: Survodutide's MASH designation signals that the glucagon arm is opening up hepatic and cardiometabolic questions, so the headline metric is no longer only a weight percentage. Third, differentiation over dominance: rather than one molecule winning outright, the class is fanning out — different receptor combinations for different research questions.
For researchers, the practical upshot is that "GLP-1" is now shorthand for a whole family. Knowing which receptors a given compound engages — and why that matters for the question you're asking — is the difference between picking a molecule and understanding it. Our receptor-by-receptor breakdown is the companion piece to this map.
The bottom line
The 2026 peptide landscape is defined by a clear arc: single GLP-1 agonists established the foundation, dual agonists (GIP/GLP-1 and GLP-1/glucagon) proved that more targets do more, the triple agonist pushed the reported effect to its current ceiling, and the amylin track opened a parallel lever. Semaglutide, Tirzepatide, Mazdutide, Survodutide, Retatrutide and Cagrilintide are the compounds carrying that story — each a legitimate research reagent, several still investigational, all supplied strictly for in vitro laboratory work.