# Retatrutide side effects in trials Canonical: https://europeanpeptideshop.com/blog/retatrutide-side-effects/ Explore the catalogue and research library. Ordering and shipping have not opened yet. Compound research · 8 November 2026 · 3 min read · By [European Peptide Shop](https://europeanpeptideshop.com/about/) ### On this page ## The short answer In published trials, the most common retatrutide side effects were gastrointestinal, such as nausea and diarrhoea, and they were more frequent in the higher dose groups. Dysaesthesia (altered skin sensation), low blood pressure and a temporary rise in heart rate were also reported more often than with placebo. These are findings for the sponsor's investigational product, given under medical supervision to selected patients. They are not a safety profile for research-grade material, and this page is not medical advice. ### TRIUMPH-2, phase 3 1,152 adults with obesity and type 2 diabetes, followed for 80 weeks (Lancet, 2026). The ranges below span the three retatrutide dose groups. Event | Retatrutide groups | Placebo Diarrhoea | 27-34% | 13% Nausea | 14-28% | 8% Dysaesthesia | 4-7% | 1% Hypotension | 1-6% | under 1% Stopped treatment permanently (adverse event or death) | 4-12% | 5% Nausea rose from the lowest to the highest dose group. Investigators judged all reported deaths unrelated to the study drug. ### Other published trials - Phase 2 (NEJM, 2023; 338 adults, 48 weeks). Gastrointestinal events were the most common, were dose-related and were mostly mild to moderate. Heart rate rose in a dose-dependent way, peaked at 24 weeks and then declined. - TRIUMPH-1, phase 3 (NEJM, 2026; 2,339 adults, 80 weeks). The most common adverse events were again gastrointestinal. ## What is not known - Long-term effects. The longest published trials ran 80 weeks. There are no multi-year safety data. - Rare events. Trials of this size cannot reliably estimate uncommon outcomes. For the wider drug class, a 2026 review reports a probable association with gallstones and no excess of pancreatitis in randomised trials, and describes retatrutide-specific data as limited. - Real-world populations. Trial participants were screened and monitored. People outside a trial differ. ## Why trial data do not describe research-grade material - Different product. The trial product was made and controlled to clinical standards under a protocol. A research vial was not. - A certificate is not a safety assessment. A batch certificate reports identity and purity. It does not establish sterility, endotoxin levels or suitability for any use in people. See [reading a peptide COA](https://europeanpeptideshop.com/blog/how-to-read-peptide-coa/) and [understanding HPLC purity](https://europeanpeptideshop.com/blog/what-hplc-purity-means/). - Anecdote is not data. Forum and social-media reports are uncontrolled and cannot show how often an effect occurs or whether the material caused it. Anyone who is unwell after using an unlicensed product should seek medical advice. ## Related pages The [retatrutide identity page](https://europeanpeptideshop.com/blog/retatrutide/) covers what the molecule is and where its development stands. The [comparison with tirzepatide and semaglutide](https://europeanpeptideshop.com/blog/retatrutide-vs-tirzepatide-vs-semaglutide/) sets out the receptor differences, and the retatrutide buying guide covers the catalogue side. Report publication status is shown in the [COA publication status](https://europeanpeptideshop.com/coa/). ## EPS documentation Use the [research catalogue](https://europeanpeptideshop.com/shop/) to check the exact name, labelled amount and format. The [COA library](https://europeanpeptideshop.com/coa/) publishes the original Janoshik reports selected for EPS, retaining the original report client name and any missing batch fields. Literature findings and another supplier's analytical results are not evidence about an EPS batch. ## Laboratory research only Materials listed on this site are supplied for in-vitro laboratory research and are not for use in or on humans or animals. They are not medicines. This article summarises published work and gives no dosing, administration, treatment or in-vivo guidance. Findings from a study apply to the material and conditions of that study, and they say nothing about any product listed here. ## References - [Bellido V, le Roux CW, Ekinci EI, et al. Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2): a double-blind, parallel-group, randomised, placebo-controlled, phase 3 trial. Lancet. 2026;408(10563):1455-1472.](https://doi.org/10.1016/S0140-6736%2826%2901861-1) - [Jastreboff AM, Kaplan LM, Davies MJ, et al. Retatrutide, a triple hormone receptor agonist, for treatment of obesity (TRIUMPH-1). N Engl J Med. 2026.](https://doi.org/10.1056/NEJMoa2604169) - [Jastreboff AM, Kaplan LM, Frías JP, et al. Triple-hormone-receptor agonist retatrutide for obesity: a phase 2 trial. N Engl J Med. 2023;389(6):514-526.](https://doi.org/10.1056/NEJMoa2301972) - [Singhani V, Ehsan M, Valencia S, et al. Gastrointestinal adverse effects of GLP-1 receptor agonists and dual GIP/GLP-1 receptor agonists: a narrative expert review. Nutr Clin Pract. 2026;41(5):1318-1333.](https://doi.org/10.1002/ncp.70180) ## Related listings [10 mg](https://europeanpeptideshop.com/shop/retatrutide-10mg/) Metabolic research ### [Retatrutide](https://europeanpeptideshop.com/shop/retatrutide-10mg/) 10 mg · Lyophilised powder Ordering opens later. Prices and availability are not yet published.[Details](https://europeanpeptideshop.com/shop/retatrutide-10mg/) ## More articles Compound research · 4 min read ## [How retatrutide targets three receptors](https://europeanpeptideshop.com/blog/retatrutide-mechanism-of-action/) How retatrutide is proposed to act at the GIP, GLP-1 and glucagon receptors, which steps are demonstrated and which are inferred. 8 November 2026 Compound research · 6 min read ## [Retatrutide research evidence](https://europeanpeptideshop.com/blog/retatrutide-research-evidence/) Retatrutide evidence by study type, including the October 2026 Ozempic comparator announcement, registry details and limits of sponsor-reported trial. 8 November 2026 Compound research · 2 min read ## [Understanding retatrutide vial labels](https://europeanpeptideshop.com/blog/retatrutide-vial/) What a retatrutide research vial contains, what 10mg looks like, and how to check a vial against its batch certificate. 8 November 2026