# Retatrutide: What the Phase 2 and Phase 3 Trials Have Actually Measured > Retatrutide is an investigational triple-agonist in Phase 3 trials. Plain-language summaries of the published obesity, diabetes, kidney, and liver-fat trial data — every figure cited. A plain-language blueprint of the published trial record — weight outcomes, kidney function, mechanism, and the safety questions still being studied. Every figure cited to source. ## The short version Retatrutide is a new kind of weight-loss and metabolic drug — but it is not approved yet. It is being studied in late-stage clinical trials run by Eli Lilly. What makes it different from other drugs in its class is that it activates three hormone receptors at once instead of one or two. Those three receptors — GIP, GLP-1, and glucagon — are signals your body already uses to regulate hunger, blood sugar, and calorie burning. By activating all three together, retatrutide has produced larger weight reductions in trials than any approved drug in its category to date. In a 48-week Phase 2 trial, people who received the highest study dose lost an average of 24.2% of their body weight [1]. A separate trial in people with type 2 diabetes showed meaningful drops in blood sugar (HbA1c — a three-month average glucose marker) alongside significant weight loss [2]. Early kidney data from 2025 also show reductions in a key marker of kidney stress (UACR — the ratio of a protein called albumin to creatinine in urine) [11]. Retatrutide is not a product you can be prescribed today. It has not been approved by the FDA or any other regulator. What this site documents is the published clinical trial record — the [Retatrutide research](/research) that explains why this compound has attracted so much attention, and what the [Retatrutide effects](/effects) data actually say, including the downsides. ## A triple-agonist in a class of dual- and single-agonists The drugs that preceded retatrutide — semaglutide and tirzepatide — each target one or two receptors. Retatrutide (also identified by its development code LY3437943) targets three. Cryo-EM structural studies — imaging methods that photograph molecular interactions at near-atomic resolution — have confirmed it simultaneously engages GLP-1R (glucagon-like peptide-1 receptor), GIPR (glucose-dependent insulinotropic polypeptide receptor), and GCGR (glucagon receptor) [3]. At the GIPR, it is approximately 8.9 times more potent than the body's own GIP hormone [3]. The glucagon receptor arm is what sets it apart mechanistically. Glucagon receptor activation increases energy expenditure — meaning the body burns more calories at rest — and accelerates the breakdown of fats in the liver. This additional mechanism is the likely contributor to the larger weight-loss figures seen in retatrutide trials compared with GLP-1 single- or dual-agonist studies [6]. For a detailed look at [how does retatrutide work](/how-it-works), the mechanism page walks through each receptor pathway and how the three arms interact. ## The kidney and metabolic data The kidney-renal angle is one of the most active areas of retatrutide research as of 2025–2026. A Phase 2 substudy published in *Kidney International Reports* measured UACR — urine albumin-to-creatinine ratio, a standard marker of kidney filtration health — and found reductions of approximately 37% in participants with type 2 diabetes and 28–31% in participants with obesity, at the highest doses studied, versus placebo [11]. Estimated glomerular filtration rate (eGFR — a calculation of how efficiently the kidneys filter blood) improved by 5.3–8.5 mL/min/1.73m² in the obesity group [11]. A Phase 3 trial specifically designed to evaluate cardiovascular and kidney outcomes — NCT06383390 — is ongoing as of 2026 [7]. The TRANSCEND-CKD trial is examining retatrutide's effects in people with chronic kidney disease specifically [12]. Results from these trials are not yet available. For the full summary of what the trials have found, see [Retatrutide results](/results). ## What retatrutide is not Retatrutide is not approved by the FDA. There is no approved dose, no approved indication, and no authorized prescription pathway as of 2026. Some gray-market vendors sell research-labeled material, but such products have no verified identity, purity, or sterility — the FDA issued warning letters to retatrutide vendors in 2025 citing violations of the Federal Food, Drug, and Cosmetic Act. This site does not sell, stock, or link to any products. It is an independent editorial publisher summarizing the peer-reviewed and clinical trial literature. The [Retatrutide references](/references) page lists every source used. Is retatrutide fda approved? No. It is investigational — in Phase 3 trials — and approval, if it comes, is contingent on those trials completing and regulatory review that has not yet occurred. --- A blueprint-level reading of the published retatrutide trial record — Phase 2 figures logged to source, the kidney and cardiac questions marked open, and no clinic, prescription, or product behind the drafting sheet.