Retatrutide and semaglutide sit at opposite ends of the incretin story: semaglutide is a well-established single GLP-1 receptor agonist, while retatrutide is an investigational triple agonist targeting GIP, GLP-1 and glucagon. Semaglutide is approved and widely used (Ozempic, Wegovy), whereas retatrutide has only completed Phase 2 studies and is not an approved medicine. Early retatrutide data show larger average weight changes than semaglutide's trials, but that evidence is far less mature. This comparison covers the mechanisms, the published trial figures and the practical differences; Body Pharm EU stocks the retatrutide side as a research pen.
| Attribute | Retatrutide | Semaglutide |
|---|---|---|
| Receptor targets | Triple agonist: GIP + GLP-1 + glucagon | Single agonist: GLP-1 |
| Drug class | Investigational triple incretin agonist | GLP-1 receptor agonist |
| Regulatory status | Investigational — Phase 2 only, not approved | Approved (EMA/FDA) |
| Brand names | None (no approved product) | Ozempic, Wegovy, Rybelsus |
| Trial weight-loss data | ~24% mean at 48 weeks, highest dose (Phase 2, NEJM 2023) | ~15% mean in obesity (STEP programme) |
| Dosing frequency | Once weekly (subcutaneous) in trials | Once weekly (subcutaneous); oral form also exists |
| Primary study focus | Obesity and metabolic disease (early stage) | Glycaemic control (SUSTAIN) and obesity (STEP) |
| Body Pharm EU availability | Research pen (not an approved medicine) | Not stocked by Body Pharm EU |
Semaglutide is a single-target GLP-1 receptor agonist — it reproduces the action of the gut hormone GLP-1 to improve insulin response, slow gastric emptying and reduce appetite. Retatrutide is a triple agonist that acts on GLP-1, GIP and the glucagon receptor simultaneously. The glucagon component is thought to increase energy expenditure and affect liver-fat metabolism, and combining three pathways is the mechanistic rationale behind the large weight changes seen in retatrutide's early studies. More receptors also means more to characterise before the compound could ever be approved.
The evidence gap between the two is wide. Semaglutide is supported by the large STEP obesity programme (~15% mean weight reduction) and the SUSTAIN diabetes programme, plus extensive real-world use. Retatrutide rests on a single Phase 2 obesity trial published in the New England Journal of Medicine in 2023, in which the highest-dose group lost about 24% of body weight at 48 weeks. Those retatrutide figures are eye-catching but preliminary — a Phase 2 signal is a long way from the confirmed, regulated efficacy that semaglutide has demonstrated across multiple Phase 3 trials.
The decisive difference is maturity and status: semaglutide is an approved medicine with years of data, while retatrutide is investigational and unapproved. They also differ in mechanism (single vs triple agonism) and in the strength of their efficacy evidence. Semaglutide additionally offers an oral formulation (Rybelsus) alongside the weekly injection; retatrutide has only been studied as a weekly subcutaneous injection. Retatrutide's larger early weight numbers should be weighed against how much less is known about it.
We stock retatrutide as a research pen — a research-grade material for laboratory use, not an approved medicine and not intended for human use. We do not carry semaglutide. This comparison is here so you can see both compounds side by side; if your interest is the retatrutide side, that is the one we supply for research contexts.
Semaglutide is the proven, approved single agonist with a deep evidence base and real-world track record, while retatrutide is the experimental triple agonist whose early results are dramatic but unconfirmed. They are not really competitors at the same stage: one is an established treatment, the other is frontier research. For an approved option the decision belongs with a healthcare professional; for research purposes, retatrutide represents the newer, more ambitious mechanism.
Retatrutide's Phase 2 trial reported a larger mean weight change (~24% at 48 weeks) than semaglutide's STEP trials (~15%), but the retatrutide data are early-stage and unconfirmed, while semaglutide has completed Phase 3 evidence and years of real-world use. "Better" depends heavily on the certainty you require.
Semaglutide targets one receptor (GLP-1). Retatrutide targets three (GIP, GLP-1 and glucagon), making it a triple agonist. The extra glucagon activity is central to why it is being studied for larger metabolic effects.
No. Semaglutide is approved by the EMA and FDA (Ozempic, Wegovy, Rybelsus). Retatrutide is investigational, has only completed Phase 2 studies, and is not approved anywhere.
No. We stock retatrutide as a research pen but do not carry semaglutide. Our research pens are research-grade materials for laboratory use, not approved medicines.
Retatrutide was studied as a once-weekly subcutaneous injection. Semaglutide is also once weekly by injection, and additionally has a daily oral form (Rybelsus).
This page is educational and intended for research and informational use only. It is not medical advice, a treatment recommendation, or dosing guidance, and it makes no promises about outcomes. Retatrutide, tirzepatide and semaglutide are the active pharmaceutical ingredients studied in clinical trials; approved medicines are supplied only through licensed pharmacies with a prescription. Body Pharm EU supplies research-grade materials for laboratory use, not approved medicines, and nothing here should be read as a substitute for advice from a qualified healthcare professional.
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