Retatrutide in Guyana: a striking trial drug approved nowhere

The drug: three hormones in one molecule

Retatrutide is a single peptide that activates three receptors: glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and glucagon¹². Tirzepatide hits the first two; semaglutide only GLP-1. The added glucagon action is meant to raise energy expenditure, and the phase 2 results in 2023 explained the excitement. In 338 adults with obesity, retatrutide 8 mg and 12 mg produced mean weight losses of 22.8 % and 24.2 % at 48 weeks, against 2.1 % with placebo¹. In 281 people with type 2 diabetes, the 12 mg dose lowered HbA1c by 2.02 points at 24 weeks, against 1.41 with dulaglutide 1.5 mg, and cut weight by 16.9 % at 36 weeks².

Phase 3: TRIUMPH-1

Eli Lilly reported TRIUMPH-1 in May 2026. The trial randomized 2,339 participants to retatrutide 4, 9 or 12 mg, titrated from 2 mg every four weeks, or placebo; at 80 weeks mean weight loss was 17.6 %, 23.7 % and 25.0 % against 3.9 % with placebo³. In an extension, 532 participants with a BMI of 35 or more were escalated to their maximum tolerated dose and reached up to 30 % weight loss at 104 weeks³. One commentator called the results "genuinely striking", noting that 30 % is "a level long associated with bariatric surgery", while adding that the full safety data "deserve careful scrutiny once peer-reviewed"³.

The safety picture is still incomplete

At the highest dose in TRIUMPH-1, nausea occurred in 42.4 %, diarrhoea in 32.0 %, constipation in 26.1 % and vomiting in 25.3 %; dysesthesia and urinary tract infections affected around 1 in 10, mostly mild to moderate³. Discontinuations for adverse events rose with dose: 4.1 % at 4 mg, 6.9 % at 9 mg and 11.3 % at 12 mg, against 4.9 % with placebo³. In phase 2, heart rate rose in a dose-dependent way, peaking at 24 weeks before declining¹. These are results from controlled trials with slow titration, medical follow-up and a pharmaceutical-grade product. None of that comes with a vial bought online.

Label disclaimers do not make it legal

Because demand ran ahead of approval, retatrutide is widely sold online as a powder in vials. In September 2025 the US Food and Drug Administration (FDA) wrote to one seller that "There are no FDA-approved applications on file for your compounded retatrutide drug products", that they were "unapproved new drugs and misbranded drugs", and that products compounded with retatrutide are not eligible for the section 503A compounding exemptions⁴. On 24 August 2026 the FDA sent warning letters to five online peptide vendors; a legal analysis noted retatrutide appeared in several, and that each letter said that "despite statements on your product labeling" the vendors' websites established the products were intended as drugs for human use⁵. The same analysis described retatrutide as unapproved anywhere in the world, with an FDA submission planned for early 2027⁵.

How Guyana's law applies

Guyana's Food and Drugs Act, Chapter 34:03, does not define a drug by its label disclaimer. A drug "includes any substance or mixture of substances manufactured, sold or represented for use" in treating a disease or "restoring, correcting or modifying organic functions"⁶. Section 22 lets inspectors sample customs entries and bars admission of any drug whose sale would break the Act, and section 3 lets the Minister order businesses to furnish particulars of the composition of substances they use in drugs and of any investigations into whether those substances are injurious to health⁶. The Government Analyst – Food and Drug Department (GA-FDD) has said "no waivers will be granted to any entity for the sale and/or distribution of unregistered drugs/medicines"⁷. A product approved nowhere cannot have been registered in Guyana.

The channels exist. In 2024 Stabroek News found an unregistered GLP-1, Ozempic, sold through medical spas, bottom-houses and a suitcase trade¹¹, and in April 2026 President Irfaan Ali's government announced an awareness campaign about self-administering treatments bought from unregulated sources, amid reports of suitcase traders and "non-refrigerated" products⁸. Guyana's customs and regulator have taken part in action against websites selling fake medicines before, in Operation Pangea V in 2012¹². The Pan American Health Organization (PAHO) warned in March 2026 that demand for these medicines may push sales into "unofficial channels, including the internet and social media", raising the risk of falsified or substandard products¹⁰. WHO adds that falsified products "deliberately misrepresent their identity, composition or source"⁹; for an unapproved powder, a buyer has no registered reference product to compare it with.