Retatrutide and kidney protection: Phase 2 post-hoc evidence and TRANSCEND-CKD

This YMYL evidence review is part of Weight Loss Rankings’ living editorial database — 300+ research articles and 190+ clinically-reviewed GLP-1 telehealth providers, sourced only from FDA prescribing information on DailyMed and peer-reviewed PubMed literature.

Retatrutide is an Eli Lilly investigational triple agonist at the GIP, GLP-1, and glucagon receptors. It is NOT FDA-approved — for chronic kidney disease, type 2 diabetes, obesity, or any other indication — anywhere worldwide as of May 2026. The published kidney evidence consists of one POST-HOC pooled analysis of two Phase 2 substudies (Heerspink 2025 Kidney Int Rep, PMID 40630318), and one design paper for the ongoing TRANSCEND-CKD Phase 2b mechanistic study (Heerspink 2025 Nephrol Dial Transplant, PMID 41160422; ClinicalTrials.gov NCT05936151). The dedicated Phase 3 cardio-kidney outcomes trial TRIUMPH-Outcomes (NCT06383390) has not yet read out. This article walks through what the post-hoc analysis actually showed, what TRANSCEND-CKD is designed to test, and how the evidence compares to the FLOW (semaglutide), SELECT (semaglutide), and SURPASS-4 (tirzepatide) kidney data.

At a glance

• Not FDA-approved. Retatrutide (LY3437943) is investigational only as of May 2026 — not approved for CKD, T2D, obesity, or any indication anywhere in the world.
• Heerspink 2025 Kidney Int Rep (PMID 40630318) is a post-hoc pooled analysis of two Phase 2 retatrutide studies (T2D n=281 and obesity-without-T2D n=338), baseline eGFR ≥45 mL/min/1.73 m2, most participants normoalbuminuric^[1].
• T2D 36-week results: retatrutide 12 mg reduced UACR by -37.0% (95% CI -57.3 to -7.0) vs placebo; eGFR was unchanged vs placebo^[1].
• Obesity 48-week results: retatrutide 8 mg / 12 mg reduced UACR by -28.0% / -31.5% and INCREASED creatinine-based eGFR by +5.3 / +8.5 mL/min/1.73 m2 vs placebo^[1].
• TRANSCEND-CKD (NCT05936151; PMID 41160422) is a Phase 2b mechanistic study, n=146 randomized, with Week 24 mGFR (iohexol clearance) as the primary endpoint, in adults with CKD (eGFR 25-75) with or without T2D^[2].
• TRIUMPH-Outcomes (NCT06383390) is the larger cardio-kidney outcomes trial cross-referenced in the TRANSCEND-CKD design paper; not yet read out^[2].
• FDA-approved comparators with kidney evidence: semaglutide (Ozempic) has the FLOW positive outcomes trial (HR 0.76) and an FDA CKD-progression label update^[3]; tirzepatide has only the SURPASS-4 post-hoc eGFR-slope analysis — no positive kidney outcomes trial^[5].

What CKD is and why GLP-1 / triple-class agonism could matter

Chronic kidney disease (CKD) is the progressive loss of kidney function. The standard staging system uses two parameters: the estimated glomerular filtration rate (eGFR), which estimates how much plasma the kidneys filter per minute per 1.73 m2 of body-surface area, and the urinary albumin-to-creatinine ratio (UACR), which measures kidney-barrier leakiness. Stages 1-2 are mild (eGFR ≥60); stage 3a is 45-59; stage 3b is 30-44; stage 4 is 15-29; and stage 5 is <15 or dialysis-dependent. The two dominant CKD drivers worldwide are type 2 diabetes and hypertension, with obesity-related glomerular hyperfiltration increasingly recognized as a third independent driver.

The therapeutic goal in CKD is to slow the progression of eGFR decline and reduce hard outcomes — kidney failure (requiring dialysis or transplant), cardiovascular death, and all-cause mortality. The current FDA-approved pharmacologic pillars are renin-angiotensin system inhibitors (ACE inhibitors and angiotensin-receptor blockers), the mineralocorticoid-receptor antagonist finerenone (in diabetic kidney disease), and the SGLT2-inhibitor class (dapagliflozin and empagliflozin have CKD progression-reduction labeling).

The GLP-1 receptor agonist class joined this list in 2024 when the FDA approved a CKD progression-risk reduction indication for Ozempic (semaglutide) on the basis of the FLOW trial (Perkovic 2024 NEJM, PMID 38785209)^[3]. For the FLOW deep-dive, see the FLOW trial and semaglutide kidney disease evidence. FLOW was the first positive kidney outcomes trial for any GLP-1-class agent and substantially changed how nephrologists frame the GLP-1 class.

The biological rationale for why the GLP-1 class could protect kidneys spans several plausible mechanisms: weight loss reduces obesity-driven glomerular hyperfiltration; glycemic control reduces hyperglycemia-driven tubular injury (in T2D); blood pressure reductions reduce mechanical stress on the glomerulus; and direct GLP-1 receptor signaling in the kidney appears to engage anti-inflammatory and natriuretic pathways. Retatrutide adds the GIP and glucagon receptor arms on top of GLP-1 agonism — whether this triple-class combination produces additive kidney protection or whether one of the arms (notably glucagon receptor agonism) could introduce off-target kidney effects is exactly what TRANSCEND-CKD is designed to evaluate.

What Heerspink 2025 Kidney Int Rep showed

Heerspink 2025 Kidney Int Rep (PMID 40630318) is the load-bearing published retatrutide kidney evidence as of 2026-05-25^[1]. Critically, it is a POST-HOC pooled analysis — not a prospective kidney outcomes trial.

Design and population:

• Source studies. Pooled post-hoc analysis of two previously-conducted Phase 2 retatrutide trials — the T2D trial (Rosenstock 2023 Lancet, PMID 37385280) and the obesity-without-T2D trial (Jastreboff 2023 NEJM, PMID 37366315). Both source trials were placebo-controlled; the T2D trial additionally included dulaglutide 1.5 mg as an active comparator.
• Sample sizes. T2D study n=281; obesity-without-T2D study n=338.
• Baseline kidney function. Inclusion required eGFR ≥45 mL/min/1.73 m2. Mean creatinine-based eGFR was approximately 91 mL/min/1.73 m2 in the T2D study and 90 mL/min/1.73 m2 in the obesity study. Median baseline UACR was 13 mg/g (T2D) and 7 mg/g (obesity) — most participants were normoalbuminuric (UACR <30 mg/g).
• Dose range. Retatrutide 0.5-12 mg weekly across ascending arms, plus placebo, plus the dulaglutide active comparator in the T2D study.
• Follow-up. Change from baseline at Week 36 (T2D source study) and Week 48 (obesity source study).

T2D 36-week kidney results (retatrutide vs placebo):

• UACR at retatrutide 12 mg: -37.0% (95% CI -57.3 to -7.0) vs placebo. Lower retatrutide doses were not specified as significantly different from placebo in the abstract.
• eGFR at retatrutide 12 mg: unchanged compared with placebo.

Obesity-without-T2D 48-week kidney results (retatrutide vs placebo):

• UACR at retatrutide 8 mg: -28.0% (95% CI -46.0 to -4.1) vs placebo.
• UACR at retatrutide 12 mg: -31.5% (95% CI -49.3 to -7.4) vs placebo.
• Creatinine-based eGFR at retatrutide 8 mg: +5.3 mL/min/1.73 m2 (95% CI 1.9-8.7) vs placebo.
• Creatinine-based eGFR at retatrutide 12 mg: +8.5 mL/min/1.73 m2 (95% CI 4.9-12.1) vs placebo.
• Cystatin-C-based and combined eGFR. Similar increases observed across these alternative eGFR estimators.

The authors’ verbatim conclusion: “Higher doses of retatrutide were associated with reduced UACR in participants with T2D and obesity, and with increased eGFR in participants with obesity but not in those with T2D.” The authors explicitly caveat that “because most patients had normal albuminuria, the absolute reduction in UACR was modest.”^[1]

Important interpretive caveats:

• Surrogate endpoints only. UACR and eGFR are surrogate markers, not hard kidney outcomes. The Phase 2 source studies were designed for glycemic and weight endpoints — not for kidney outcomes. The Heerspink kidney analysis is post-hoc.
• Selected baseline kidney function. Inclusion required eGFR ≥45 — so CKD stages 3b, 4, and 5 are not represented. Patients with established CKD (the population FLOW enrolled for semaglutide) are largely not represented.
• Normoalbuminuric population. Median baseline UACR was 7-13 mg/g — well below the macroalbuminuria threshold of 300 mg/g that FLOW enrolled. Percent changes from a near-normal baseline translate into very small absolute changes in albumin excretion.
• Discordant T2D vs obesity eGFR signal. The eGFR increase was observed only in the obesity arm — not in T2D. The mechanistic explanation is not specified in the abstract.
• No BP data extracted. Blood pressure changes per arm were not extracted in the published abstract. BP is a plausible mediator of kidney effects but is not cited in this article because it was not in the abstract verification pass.

TRANSCEND-CKD: what the Phase 2b mechanistic study is testing

TRANSCEND-CKD (ClinicalTrials.gov NCT05936151) is the dedicated retatrutide-in-CKD mechanistic trial. The design paper is Heerspink 2025 Nephrol Dial Transplant (PMID 41160422)^[2].

Design and population:

• Trial design. Double-blind, placebo-controlled, Phase 2b mechanistic study. Adults with overweight or obesity and chronic kidney disease.
• Population. Adults with eGFR 25-75 mL/min/1.73 m2, with or without T2D. 37.7% of participants had T2D (HbA1c 7.1% SD 1.1%); non-T2D participants had HbA1c 5.7% (SD 0.3%).
• Randomization. 367 screened, 146 randomized 1:1 to once-weekly retatrutide titrated to maximum tolerated dose up to 12 mg, or matched placebo.
• Baseline characteristics. Mean age 65.1 years (SD 10.6), 45.2% female, 69.9% White, mean weight 101.1 kg (SD 20.6), mean BMI 35.7 kg/m2 (SD 6.1).
• Baseline kidney function. Mean measured GFR (mGFR) 49.3 mL/min/1.73 m2 (SD 19.0); cystatin-C-based eGFR 49.6 mL/min/1.73 m2 (SD 13.2); creatinine-based eGFR 64.2 mL/min/1.73 m2 (SD 17.8); median baseline UACR 14.0 mg/g (IQR 6.0-69.0). 21.8% of participants were on SGLT2 inhibitors at baseline.
• Primary objective. Change in measured glomerular filtration rate (mGFR) by iohexol clearance from baseline to Week 24.
• Additional objectives. MRI-assessed kidney hemodynamic and volumetric measurements, including perirenal and renal sinus fat.
• Treatment duration. Primary endpoint at Week 24.
• Estimated primary-completion date. Not specified in the published abstract — consult the ClinicalTrials.gov NCT05936151 listing for the current estimated completion date.

Two important design features distinguish TRANSCEND-CKD from prior retatrutide kidney data:

1. Measured GFR (mGFR) by iohexol clearance is the gold-standard direct measurement of glomerular filtration. It is more accurate than the creatinine- or cystatin-C-based estimating equations used in routine practice. Surrogate endpoints based on estimated GFR can be confounded by changes in muscle mass and tubular handling; iohexol clearance avoids those confounders.
2. CKD-enriched population. Mean baseline mGFR was 49.3 mL/min/1.73 m2 (corresponding to roughly CKD stage 3a) with inclusion down to eGFR 25 (stage 4). This is substantially more impaired than the Heerspink 2025 post-hoc population (baseline eGFR ≥45, mean ≈90).

TRANSCEND-CKD will be a mechanistic readout, not a hard outcomes trial. The design paper explicitly cross-references TRIUMPH-Outcomes (NCT06383390) as the larger cardio-kidney outcomes trial that TRANSCEND-CKD is intended to inform^[2]. TRIUMPH-Outcomes — if it reads out with a positive primary endpoint — would be the basis for any future FDA CKD label indication for retatrutide. As of May 25, 2026, neither trial has published primary results.

For the broader retatrutide regulatory and clinical-trial timeline, see retatrutide triple-agonist evidence review and retatrutide for type 2 diabetes evidence.

Cross-class context: FLOW (semaglutide in T2D + CKD)

FLOW (Perkovic 2024 NEJM, PMID 38785209) is the load-bearing positive kidney outcomes trial for the GLP-1 receptor agonist class^[3]. Design and headline results:

• ClinicalTrials.gov NCT03819153.
• Population. Adults with T2D and CKD, defined as eGFR 50-75 mL/min/1.73 m2 with UACR 300-5000, OR eGFR 25 to <50 with UACR 100-5000. n=3,533 randomized (1,767 semaglutide, 1,766 placebo).
• Intervention. Subcutaneous semaglutide 1.0 mg weekly vs placebo, on a background of standard kidney-protective care.
• Median follow-up. 3.4 years — trial stopped early at a prespecified interim analysis after the predetermined number of primary events accumulated.
• Primary composite outcome (kidney failure, sustained ≥50% eGFR reduction, kidney death, or CV death): 331 events in the semaglutide group vs 410 events in the placebo group.Hazard ratio 0.76 (95% CI 0.66-0.88, P=0.0003) — a 24% relative risk reduction.
• eGFR slope. Annual eGFR decline was 1.16 mL/min/1.73 m2 slower in the semaglutide group (P<0.001).

FLOW supported an FDA label update for Ozempic to include reduction in the risk of CKD progression in adults with T2D and CKD. The label-update mechanism makes Ozempic the only GLP-1-class agent with an explicit FDA-recognized kidney-protection indication as of May 2026. For the FLOW deep-dive, see the FLOW trial and semaglutide kidney disease evidence.

The interpretive bottom line for retatrutide vs FLOW: FLOW used hard kidney outcomes (kidney failure, ≥50% eGFR loss, kidney death) in a CKD-enriched, macroalbuminuric population over 3.4 years. The Heerspink 2025 retatrutide post-hoc used surrogate UACR and eGFR changes over 36-48 weeks in a non-CKD, mostly normoalbuminuric population. These are not comparable evidence bases. Retatrutide has no analogous outcomes-trial evidence today — TRIUMPH-Outcomes is the trial that, if positive, would generate it.

Cross-class context: SELECT renal subgroup (semaglutide in obesity)

SELECT renal subgroup (Colhoun 2024 Nat Med, PMID 38796653) is the dedicated kidney-outcomes analysis from the SELECT cardiovascular outcomes trial in adults with obesity and established CV disease^[4]. The parent CV-outcomes paper is Lincoff PMID 37952131 (not cited here for kidney-specific data).

• ClinicalTrials.gov NCT03574597.
• Pre-specified main composite kidney endpoint: death from kidney disease, initiation of chronic kidney replacement therapy, persistent eGFR <15 mL/min/1.73 m2, persistent ≥50% eGFR reduction, or persistent macroalbuminuria.
• Result: 1.8% semaglutide vs 2.2% placebo, HR 0.78 (95% CI 0.63-0.96, P=0.02).
• eGFR treatment benefit at 104 weeks: 0.75 mL/min/1.73 m2 (95% CI 0.43-1.06, P<0.001) overall; 2.19 mL/min/1.73 m2 (95% CI 1.00-3.38, P<0.001) in the baseline eGFR <60 subgroup.

SELECT extends the GLP-1-class kidney signal into the obesity population without T2D — an arguably closer population to the Heerspink 2025 obesity arm than FLOW’s T2D + CKD population. The hazard ratio (0.78) for the SELECT renal composite is similar to FLOW’s 0.76 for the T2D + CKD primary composite. Both establish that the semaglutide kidney signal is reproducible across distinct populations. Retatrutide does not yet have comparable hard-outcomes data.

Cross-class context: SURPASS-4 (tirzepatide renal substudy)

SURPASS-4 renal substudy (Heerspink 2022 Lancet Diabetes Endocrinol, PMID 36152639) is the closest tirzepatide-class kidney data point^[5].

• ClinicalTrials.gov NCT03730662.
• Population. Adults with T2D treated with metformin, sulfonylurea, or SGLT2 inhibitor; HbA1c 7.5-10.5%; BMI ≥25; established CV disease or high CV risk. n=2,002 randomized (997 tirzepatide pooled, 1,005 insulin glargine).
• Baseline. Mean eGFR 81.3 (SD 21.11) mL/min/1.73 m2; median UACR 15.0 mg/g (IQR 5.0-55.8). Median treatment duration 85 weeks (up to 104 weeks).
• eGFR slope result. Mean annual eGFR decline -1.4 (SE 0.2) mL/min/1.73 m2/yr in pooled tirzepatide arms vs -3.6 (SE 0.2) mL/min/1.73 m2/yr in insulin glargine — between-group difference 2.2 mL/min/1.73 m2/yr (95% CI 1.6-2.8).

Important caveats: SURPASS-4 is a post-hoc kidney analysis of an open-label trial whose primary endpoint was HbA1c, not kidney outcomes. The active comparator was insulin glargine, which has its own metabolic profile and is not a placebo. The eGFR-slope difference is suggestive of a tirzepatide kidney benefit but does not constitute a positive Phase 3 kidney outcomes trial. As of May 2026, tirzepatide has no FDA-recognized kidney-protection indication. A dedicated Phase 3 tirzepatide kidney outcomes trial is required to establish that.

For the cross-class context bottom line: semaglutide (FLOW + SELECT renal) has Phase 3 hard-outcomes evidence with an FDA label update; tirzepatide (SURPASS-4) has post-hoc Phase 3 eGFR-slope evidence only; retatrutide (Heerspink 2025) has post-hoc Phase 2 surrogate evidence only. TRANSCEND-CKD and TRIUMPH-Outcomes are the trials that, if positive, would put retatrutide closer to the semaglutide position. None have yet read out.

Mechanism: how triple-class agonism could affect renal parameters

As of May 2026 there is no published retatrutide-specific kidney mechanism paper — the original Coskun 2022 Cell Metab pharmacology paper (PMID 35985340) characterizes receptor binding, signaling, and glycemic/weight effects but does not perform renal-specific mechanism analysis^[8]. The mechanism discussion below is INFERRED from the broader incretin literature and is not retatrutide-specific.

Plausible mechanisms by which retatrutide could influence renal parameters:

• Weight loss and reduction of obesity-related glomerular hyperfiltration. Phase 2 retatrutide produced 24% weight loss at 48 weeks at the 12 mg dose in the obesity trial (Jastreboff 2023, PMID 37366315)^[6]. Weight loss reduces glomerular hyperfiltration and intraglomerular pressure — potentially explaining the +5.3 / +8.5 mL/min/1.73 m2 creatinine-eGFR increase observed in the obesity arm of Heerspink 2025. (Note: an isolated eGFR increase is not unambiguously beneficial — it could represent recovery from prior hyperfiltration OR could reflect changes in serum creatinine production driven by lean-mass changes.)
• Glycemic control reducing tubular injury. In T2D, retatrutide produced HbA1c reductions up to -2.02% at 24 weeks in the Rosenstock 2023 Phase 2 trial (PMID 37385280)^[7]. Improved glycemia reduces hyperglycemia-driven tubular toxicity, a plausible mediator of the T2D UACR reduction.
• Blood pressure reduction. The GLP-1 class is known to produce modest BP reductions. The Heerspink 2025 abstract did NOT report BP changes per arm so this article cannot quote retatrutide-specific BP magnitudes. Full text of PMC12231004 may contain these data.
• Direct GLP-1 receptor signaling in the kidney.GLP-1 receptors are expressed in renal proximal tubule and macula densa cells. GLP-1R signaling is associated with natriuresis, anti-inflammatory effects, and inhibition of oxidative-stress pathways in preclinical kidney models. Whether these effects scale to clinically meaningful kidney protection in humans treated with retatrutide is unknown.
• Glucagon receptor agonism — theoretical risks and benefits. Glucagon receptor agonism could engage hepatic- renal axis pathways and increase energy expenditure, but in isolation could increase amino acid catabolism and urea load. The retatrutide-specific renal balance between GLP-1R benefit and any off-target glucagon-receptor effects is exactly what TRANSCEND-CKD’s direct mGFR measurement (iohexol clearance) and MRI hemodynamic measures are designed to characterize.

The honest mechanism summary: triple-class agonism plausibly engages multiple kidney-protective levers, but as of May 2026 there is no retatrutide-specific renal-mechanism paper analogous to the Coskun 2022 pharmacology paper. Mechanism remains hypothesis, not established fact, until TRANSCEND-CKD reads out.

What is not yet known about retatrutide and kidneys

• Phase 3 hard kidney outcomes. No Phase 3 trial of retatrutide has read out with a primary kidney endpoint as of May 2026. TRIUMPH-Outcomes (NCT06383390) is the relevant trial; not yet published.
• Hard endpoints — dialysis, transplant, kidney death. Heerspink 2025 measured UACR and eGFR, not hard outcomes. TRANSCEND-CKD measures mGFR by iohexol, also not a hard outcome. Whether retatrutide reduces dialysis, transplant, or kidney death is unknown.
• CKD stages 3b, 4, 5. Heerspink 2025 required baseline eGFR ≥45 — so CKD stage 3b (eGFR 30-44), 4 (15-29), and 5 (<15 or dialysis-dependent) are not represented. TRANSCEND-CKD extends down to eGFR 25 but the sample size is small (n=146) and primary endpoint is Week 24 mGFR change, not outcomes.
• Non-diabetic CKD. The retatrutide kidney evidence base is dominated by T2D (Rosenstock 2023 source) and obesity source studies. Non-T2D, non-obesity primary CKD etiologies (IgA nephropathy, polycystic kidney disease, glomerulonephritis, membranous nephropathy) have no retatrutide data.
• Macroalbuminuric CKD. Most participants in the Heerspink 2025 source studies were normoalbuminuric (median UACR 7-13 mg/g). The macroalbuminuric population that FLOW enrolled (UACR >300) is not adequately represented.
• Pediatric and post-transplant CKD. No data.
• Long-term durability. Heerspink 2025 measured at 36 weeks (T2D) and 48 weeks (obesity). Whether UACR reductions and eGFR increases sustain over multi-year follow-up is unknown.
• BP-mediated vs direct renal mechanism. Without per-arm BP data in the verified abstract, the contribution of BP changes to the observed UACR / eGFR signal cannot be quantified.

Practical takeaway for patients with CKD or kidney concerns

Retatrutide cannot be prescribed for CKD or for kidney protection today. Practical implications:

• Retatrutide is investigational only. Not FDA-approved for any indication, anywhere worldwide, as of May 2026. Patients with CKD should NOT seek out compounded retatrutide for kidney protection — any source dispensing it is operating outside the FDA-regulated supply chain and the FDA has explicitly stated retatrutide may not lawfully be compounded under section 503A of the Federal Food, Drug, and Cosmetic Act. CKD adds additional patient-specific risk: reduced renal clearance can amplify the effects of contaminants, dose errors, or off-target ingredients in unverified compounded preparations. See retatrutide buy / regulatory sourcing evidence for the regulatory framing.
• The FDA-approved GLP-1 with kidney-protection labeling is semaglutide (Ozempic). The FLOW trial (Perkovic 2024 NEJM) supported a CKD progression-risk reduction label update. For patients with T2D and CKD, this is the GLP-1-class option with the strongest FDA-recognized renal evidence today^[3]. See the FLOW trial and semaglutide kidney disease evidence.
• Tirzepatide does not have a positive Phase 3 kidney outcomes trial or an FDA renal-protection label as of May 2026. SURPASS-4 post-hoc data suggests slower eGFR decline vs insulin glargine but is not the same evidence standard.
• SGLT2 inhibitors (dapagliflozin, empagliflozin) remain a foundational kidney-protective class with FDA-recognized CKD-progression labeling. ACE inhibitors and angiotensin-receptor blockers remain the foundational RAAS-blockade class. Mineralocorticoid-receptor antagonists (finerenone) add an additional pillar in diabetic kidney disease.
• For obesity-related glomerular hyperfiltration without T2D — the SELECT renal subgroup (semaglutide) is the closest published evidence base. The Heerspink 2025 retatrutide obesity-arm eGFR signal is intriguing but is a post-hoc Phase 2 surrogate endpoint, not a hard outcome.
• If TRANSCEND-CKD reads out positively for mGFR improvement at Week 24, AND TRIUMPH-Outcomes reads out positively for hard cardio-kidney outcomes, AND FDA approves retatrutide for a CKD-related indication — then the practical positioning of retatrutide vs the existing kidney-protective pillars will need to be re-evaluated. Until those trials read out, retatrutide-for-CKD remains hypothesis only.
• Defer to a licensed prescriber and a nephrologist for any CKD treatment decision. This article is educational content about the published evidence base, not a recommendation to use any specific therapy. Patients with CKD have additional considerations — drug-clearance, RAAS-blockade interactions, electrolyte management — that require nephrology input.

Frequently asked questions

Related research

• Retatrutide triple-agonist evidence review — broader Phase 2 obesity and T2D data, mechanism, and the safety profile across indications.
• Retatrutide for type 2 diabetes evidence — the Phase 2 Rosenstock 2023 T2D trial in detail (one of the two source studies for the Heerspink 2025 kidney post-hoc).
• FLOW trial and semaglutide kidney disease evidence — the Phase 3 kidney outcomes trial that supports the Ozempic CKD progression-risk label.
• Retatrutide buy and regulatory sourcing evidence — the FDA prohibition on compounded retatrutide and the regulatory framing of investigational-only access.

Important disclaimer. This article is educational information only — not medical advice and not a substitute for consultation with a licensed prescriber and nephrologist. Retatrutide (LY3437943) is an investigational compound. It is NOT FDA-approved for chronic kidney disease, type 2 diabetes, obesity, or any other indication, anywhere worldwide as of May 2026. Treatment decisions for CKD must be made with a licensed prescriber and ideally a nephrologist using FDA-approved medications. Every clinical claim in this article is anchored to a primary source (peer-reviewed PubMed literature with verified PMIDs verified live on 2026-05-25). Weight Loss Rankings does not prescribe, dispense, or endorse any specific medication or pharmacy.