Published · Aurelis Peptides
Retatrutide and tirzepatide attract attention because of their weight-loss research. The first difference is straightforward: retatrutide acts at three hormone receptors, while tirzepatide acts at two. The useful comparison goes beyond counting targets. It also considers the trial population, the time measured and the exact catalogue specification.
This guide compares selected primary studies from 2022, 2023 and September 2026. It brings the main differences together without turning results from separate trials into a ranking.
Retatrutide vs tirzepatide at a glance
| Compare | Retatrutide | Tirzepatide |
|---|---|---|
| Receptor targets | GIP, GLP-1 and glucagon | GIP and GLP-1 |
| Common description | Triple-receptor agonist | Dual-receptor agonist |
| Selected weight-loss studies here | 2023 phase 2 trial and 2026 TRIUMPH-1 phase 3 trial | 2022 SURMOUNT-1 phase 3 trial |
| Aurelis catalogue content | 30 mg / 40 mg / 50 mg / 60 mg per unit | 30 mg / 40 mg / 50 mg / 60 mg per unit |
Triple vs dual: what do the names mean?
A receptor is a target through which a signal can affect a cell. An agonist activates that target. In these papers, GIP means glucose-dependent insulinotropic polypeptide, and GLP-1 means glucagon-like peptide-1. Both peptides act at those receptors; retatrutide also acts at the glucagon receptor.
This extra target distinguishes the molecular profiles. The number of targets alone does not tell you how much weight a person will lose or how a particular material will perform. The clinical studies provide the measured outcomes. Retatrutide receptor profile · Tirzepatide receptor profile.
Tirzepatide: weight-loss results in SURMOUNT-1
The 2022 SURMOUNT-1 trial enrolled 2,539 adults with obesity, or overweight plus a weight-related complication, without diabetes. The study compared tirzepatide groups with placebo over 72 weeks.
Average weight reductions across the three tirzepatide groups were 15.0%, 19.5% and 20.9%, compared with 3.1% in the placebo group. These are the paper’s treatment-regimen estimates, which assessed effects regardless of treatment discontinuation. Gastrointestinal events were the most common adverse events. Read the original SURMOUNT-1 paper.
Retatrutide: the 2023 trial and a 2026 update
The 2023 phase 2 trial enrolled 338 adults with obesity, or overweight plus a weight-related condition. Its primary weight endpoint was at 24 weeks. The frequently discussed 48-week results were a secondary endpoint: average reductions ranged from 8.7% to 24.2% across retatrutide groups, versus 2.1% with placebo. Read the 2023 retatrutide trial.
A larger phase 3 report, TRIUMPH-1, was published on 29 September 2026. It enrolled 2,339 adults with obesity without diabetes and followed treatment for 80 weeks. The reported average weight reductions were 17.6%, 23.7% and 25.0% across retatrutide groups, compared with 3.9% with placebo, using an intention-to-treat approach. Gastrointestinal events were the most common adverse events. Read the primary TRIUMPH-1 report.
Why the biggest percentage is not a head-to-head answer
The results above come from separate placebo-controlled trials. Neither of these retatrutide papers directly tested retatrutide against tirzepatide. The trial lengths also differ: 48, 72 and 80 weeks are different points on a weight-change timeline.
When comparing a headline, keep the study year, participants, endpoint and analysis method beside the number. An average describes a study group; it does not predict an individual outcome. The results characterise the clinical trial materials and populations, rather than an Aurelis catalogue unit.
For broader context, explore the metabolic peptide overview. For the specific names and specifications, open the individual retatrutide and tirzepatide profiles.
30 mg, 40 mg, 50 mg and 60 mg: what the listings tell you
Aurelis lists both peptides at 30 mg, 40 mg, 50 mg and 60 mg per unit. These figures describe catalogue content. They are not a dose, concentration, treatment schedule or comparison of biological activity.
A 50 mg retatrutide listing and a 50 mg tirzepatide listing name different molecules with the same listed mass. Keep the compound name attached to the amount when requesting a catalogue or batch record. Match the identity and content information to the selected item; a purity percentage answers a different question from the amount present.
Compare vials and kits with a precise enquiry
Aurelis presents both branded vials and pen-style kits. Confirm the format available for the specific peptide and content option you want to discuss. A product image represents a presentation; the selected item’s specification should identify its contents and complete packaging.
Include the peptide name, listed content, preferred presentation and destination in Australia, Canada or the USA. Request the matching batch documents and confirmation of local availability. Our vial and kit format guide and quality documentation guide help organise those questions.
Send a retatrutide or tirzepatide enquiry, or email sales@aurelispeptides.com with the entries you want to compare.
Primary research sources
- Jastreboff et al. · SURMOUNT-1 · 2022 — tirzepatide, 2,539 adults and the 72-week weight endpoint.
- Jastreboff et al. · Retatrutide phase 2 · 2023 — 338 adults; primary 24-week and secondary 48-week endpoints.
- Jastreboff et al. · TRIUMPH-1 · September 2026 — retatrutide, 2,339 adults and the 80-week weight endpoint.