# Retatrutide Retatrutide is investigational: it is still in clinical trials, and FDA has not approved it for any use. The evidence grade is moderate-human for weight loss and blood sugar in trials of up to 80 weeks. Pharmacies may not make it, and versions sold online are illegal. Status checked: 2026-10-24. Last verified: 2026-10-26. Primary source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss This page has not been individually reviewed by a clinician. Information, not medical advice. | Fact | Value | Tier | Checked | Source | |---|---|---|---|---| | Also called | LY3437943 | peer-reviewed | 2026-10-24 | [source](https://pubmed.ncbi.nlm.nih.gov/37366315/) | | Class | dual-or-triple-agonist | peer-reviewed | 2026-10-24 | [source](https://pubmed.ncbi.nlm.nih.gov/37366315/) | | Regulatory status | investigational | primary | 2026-10-24 | [source](https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss) | | Status source read | 2026-10-23 | primary | 2026-10-24 | [source](https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss) | | Evidence grade | moderate-human | our assessment | 2026-10-24 | [source](https://peptideindex.ai/methodology#evidence-grade) | ## Name Retatrutide Source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss ## Summary An experimental weekly shot that acts on three hormones, GIP, GLP-1 and glucagon. It is in late-stage trials for obesity and diabetes and is not approved. Source: https://pubmed.ncbi.nlm.nih.gov/42810372/ ## Short answer Retatrutide is investigational: it is still in clinical trials, and FDA has not approved it for any use. The evidence grade is moderate-human for weight loss and blood sugar in trials of up to 80 weeks. Pharmacies may not make it, and versions sold online are illegal. Source: https://peptideindex.ai/methodology#short-answer ## Known risks - In trials, the most common problems were nausea, diarrhea, vomiting and constipation. They were more common at higher strengths [^9] [^10]. - In a mid-stage trial, heart rate went up more at higher strengths. It peaked at 24 weeks and then came down [^9]. - In an 80-week trial, low blood pressure and odd skin feelings, such as tingling or burning, happened more often than on a dummy shot [^13]. - In that trial, more people on the two higher strengths stopped the drug for good because of bad reactions or death than on a dummy shot [^13]. - One vial sold as retatrutide in a New York corner store held no peptide at all. Lab tests found a filler and live bacteria in it [^16]. - FDA warns that shots skip some of the body's defenses. Germs or toxins in an untested product can cause life-threatening illness [^5]. Source: https://pubmed.ncbi.nlm.nih.gov/42810372/ ## What nobody knows yet - The longest published trial lasted 80 weeks. Nobody knows what years of use do to the body [^13]. - The published trials measured weight, blood sugar and liver fat. None has shown yet whether it prevents heart attacks, strokes or early death [^12] [^13]. - The liver fat results come from 98 people in one trial. A much larger liver trial is still running [^11] [^7]. - Nobody can tell what is in a product sold online. Two online samples matched a basic lab standard, but that standard is not the drug used in trials [^16]. - Nobody knows if FDA will approve it. Its maker plans to ask for approval in early 2027 [^8] [^15]. Source: https://pubmed.ncbi.nlm.nih.gov/42810372/ ## What it is Retatrutide is an experimental drug given as a weekly shot under the skin [^9]. It acts on three hormones that help control blood sugar and body weight: GIP, GLP-1 and glucagon [^10]. That is why researchers call it a triple-hormone agonist [^9]. An agonist is a drug that switches on the same signal as a natural hormone. Its lab code is LY3437943 [^9]. Online sellers often call it Reta [^16]. One drug company developed it and has paid for every large trial so far [^9] [^12] [^13]. It is not sold in any pharmacy, and FDA has not approved it for any condition [^1]. Source: https://pubmed.ncbi.nlm.nih.gov/37366315/ ## Where it stands legally Retatrutide is investigational: it is being tested in clinical trials, and FDA has not approved it for any use [^1]. That does not make it legal to sell, and it does not let pharmacies make it. Checked 23 October 2026. It is being studied for obesity, type 2 diabetes and a fatty liver disease [^7] [^13]. Online, it is sold for weight loss, often with a label saying it is for research only [^1] [^16]. Under federal law, pharmacies may not use it to make drugs [^1]. It has no official quality standard and is not part of any approved drug. It is also not on either list of raw ingredients that pharmacies or outsourcing facilities may use [^3]. A research-use label does not change this. When a seller's site shows the product is meant for people, FDA treats it as an unapproved new drug [^2] [^5]. Shipping an unapproved new drug across state lines breaks federal law [^6]. It is not approved anywhere in the world [^8]. Its maker plans to ask FDA for approval in early 2027 [^8] [^15]. In August 2026, the maker sued six companies that sold versions of it [^15]. Source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss ## What the evidence shows The evidence grade is moderate-human: trials in people show large weight loss and better blood sugar, but they are short and the maker paid for all of them [^9] [^12] [^13]. A mid-stage trial of 338 adults with obesity ran for 48 weeks. People on the highest strength lost about 24% of their weight. People on a dummy shot lost about 2% [^9]. A mid-stage trial of 281 adults with type 2 diabetes found lower HbA1c, a blood test of average blood sugar over about three months [^10]. In a group of 98 people with fatty liver, liver fat fell by more than 80% on the higher strengths [^11]. Two late-stage trials have now been published. In 537 adults with type 2 diabetes, HbA1c fell by about 1.7 to 1.9 points over 40 weeks, against 0.8 on a dummy shot. Weight fell by 11% to 15% [^12]. In 1,152 adults with obesity and type 2 diabetes, weight fell by 12% to 19% over 80 weeks, against 5% on a dummy shot [^13]. A 2025 review of four trials found it beat a dummy shot on every measure it pooled [^14]. These trials tested the maker's own drug. They tell us nothing about products sold online, which may hold something else [^16]. Source: https://pubmed.ncbi.nlm.nih.gov/42810372/ ## Legitimate ways to get it The only legal way to get retatrutide in the US is to join a clinical trial [^1] [^7]. No approved product exists, and no pharmacy may lawfully make it [^1] [^3]. On 23 October 2026 the official trial registry listed two studies open to new people [^7]. One is a large late-stage study of fatty liver disease with sites in many US states. The other is a smaller study with one site in China [^7]. Each trial has strict rules on who may join. Open trials are listed in the trials block below, with the date the official registry was last checked. Source: https://clinicaltrials.gov/api/int/studies?query.intr=retatrutide&filter.overallStatus=RECRUITING,NOT_YET_RECRUITING&limit=50&fields=NCTId,BriefTitle,OfficialTitle,OverallStatus,Phase,LeadSponsorName,Condition,InterventionName,LocationState,LocationCountry,BriefSummary,StartDate,LastUpdatePostDate ## How people are getting it anyway This section describes what happens and is not a recommendation. Retatrutide reaches people outside trials in three main ways, and none of them is legal [^1]. The first is online sellers that label it for research use. FDA sent warning letters to such sellers in December 2024, March 2026 and August 2026 [^2] [^5] [^6]. In 2026, a news team also found it for sale in New York corner stores [^16]. The second is businesses that offer it as a compounded drug. FDA warned two of them in September 2025 [^3] [^4]. The third is online health businesses that sell it after a short form. FDA says it has warned such companies [^1]. A news team ordered it from two such sites, and at least one order arrived with no consultation [^16]. In each case, nobody checks what is in the vial [^1]. One vial a news team tested held no peptide, a filler and live bacteria [^16]. In court, the maker says these products are more likely to hold contaminants [^15]. It has sued six companies and reported more than 200 others to officials [^8] [^15]. Source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss ## Access routes Source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss ### Clinical trial Detail: Retatrutide is only available inside clinical trials. Open trials are listed in the trials block below, with the date the official registry was last checked. Source: https://clinicaltrials.gov/study/NCT07165028 ## Unofficial channels Source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss ### Research use seller What it is: Sold online, and in some corner stores, in vials labeled for research use only or not for human use. Legal position: FDA treats these as unapproved new drugs when the seller's site shows they are meant for people, whatever the label says. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/prime-vitality-inc-dba-prime-peptides-695156-12102024) Documented risks: - A vial sold as retatrutide held no peptide. Lab tests found a filler and 13 colonies of bacteria. (source: https://www.cbsnews.com/news/tested-experimental-weight-loss-drug-results/) - FDA warns that injected products skip some of the body's defenses, so toxins or germs in them can cause life-threatening illness. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/gram-peptides-721806-03312026) - FDA says these products are of unknown quality and may harm health. (source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss) Enforcement: - 2024-12-10: FDA warning letter to an online seller of research-use peptides, including retatrutide. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/prime-vitality-inc-dba-prime-peptides-695156-12102024) - 2026-03-31: FDA warning letter to an online seller of research-use retatrutide. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/gram-peptides-721806-03312026) - 2026-08-24: FDA warning letter to an online seller of research-use peptides, including retatrutide. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/peak-performance-peptides-735127-08242026) Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/prime-vitality-inc-dba-prime-peptides-695156-12102024 ### Compounding outside the rules What it is: Versions offered as compounded drugs by online businesses and pharmacies, made from raw ingredient bought from distributors. Legal position: Retatrutide cannot be used in compounding under federal law. It is not part of any approved drug and is on no list of allowed raw ingredients. (source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss) Documented risks: - FDA does not check compounded drugs for safety, quality or whether they work before they are sold. (source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss) - One business told buyers that compounded retatrutide was the active ingredient in approved weight-loss drugs. FDA said that claim was false. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/genlabmeds-713650-09092025) Enforcement: - 2025-09-09: FDA warning letter to an online business offering compounded retatrutide. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/genlabmeds-713650-09092025) - 2025-09-09: FDA warning letter to a second online business offering compounded retatrutide. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/medclub-dr-jenn-712126-09092025) Source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss ### Telehealth What it is: Online health businesses that sell it after a short online form, sometimes promising a review by a doctor or nurse. Legal position: FDA has warned telehealth companies for marketing unapproved drugs such as retatrutide, including directly to consumers. (source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss) Documented risks: - A news team ordered it from two such sites. At least one order arrived with no talk with a health worker. (source: https://www.cbsnews.com/news/tested-experimental-weight-loss-drug-results/) Source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss ## Recruiting trials Snapshot date: 2026-10-24. A listing is not a recommendation. Trials have strict eligibility rules. Talk to your doctor and read the official record. - nct NCT07467447, url https://clinicaltrials.gov/study/NCT07467447, phase Phase 2, title Effect of LY3437943 Versus Placebo in Participants Who Have Obesity or Are Overweight, status recruiting, sponsor Hudson Biotech, countries China, us states none listed - nct NCT07165028, url https://clinicaltrials.gov/study/NCT07165028, phase Phase 3, title Withheld under our publishing rules. Read it in the official record., status recruiting, sponsor Eli Lilly and Company, countries United States, Argentina, Australia, Austria, Belgium, Brazil, Bulgaria, Canada, China, Czechia, France, Germany, Hong Kong, Hungary, India, Israel, Italy, Japan, Mexico, Netherlands, New Zealand, Norway, Poland, Portugal, Puerto Rico, Romania, South Korea, Spain, Sweden, Switzerland, Taiwan, Turkey (Türkiye), Ukraine, United Kingdom, us states Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nevada, New Jersey, New Mexico, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Utah, Virginia, Washington, West Virginia Source: https://clinicaltrials.gov/api/v2/studies?query.intr=retatrutide+OR+LY3437943&filter.overallStatus=RECRUITING%2CNOT_YET_RECRUITING&pageSize=50&sort=StartDate%3Adesc&countTotal=true&fields=NCTId%2CBriefTitle%2COverallStatus%2CPhase%2CLeadSponsorName%2CStartDate%2CLocationCountry%2CLocationState ## Sources Source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss ### 1. FDA: concerns with unapproved GLP-1 drugs used for weight loss, updated 1 October 2026 Type: regulatory Tier: primary Source: https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss ### 2. FDA warning letter to an online seller of research-use peptides, 10 December 2024 Type: regulatory Tier: primary Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/prime-vitality-inc-dba-prime-peptides-695156-12102024 ### 3. FDA warning letter on compounded retatrutide, 9 September 2025 Type: regulatory Tier: primary Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/genlabmeds-713650-09092025 ### 4. FDA warning letter on compounded retatrutide, 9 September 2025, second business Type: regulatory Tier: primary Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/medclub-dr-jenn-712126-09092025 ### 5. FDA warning letter to an online seller of research-use retatrutide, 31 March 2026 Type: regulatory Tier: primary Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/gram-peptides-721806-03312026 ### 6. FDA warning letter to an online seller of research-use peptides, 24 August 2026 Type: regulatory Tier: primary Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/peak-performance-peptides-735127-08242026 ### 7. ClinicalTrials.gov: recruiting and not yet recruiting studies of retatrutide Type: reference Tier: primary Source: https://clinicaltrials.gov/api/int/studies?query.intr=retatrutide&filter.overallStatus=RECRUITING,NOT_YET_RECRUITING&limit=50&fields=NCTId,BriefTitle,OfficialTitle,OverallStatus,Phase,LeadSponsorName,Condition,InterventionName,LocationState,LocationCountry,BriefSummary,StartDate,LastUpdatePostDate ### 8. ArentFox Schiff: research-use labels are not a legal strategy, 18 September 2026 Type: legal-analysis Tier: legal-analysis Source: https://www.afslaw.com/perspectives/alerts/ruo-ined-five-peptide-vendors-learn-research-use-only-not-legal-strategy ### 9. Phase 2 trial of retatrutide in adults with obesity, 2023 Type: rct Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/37366315/ ### 10. Phase 2 trial of retatrutide in adults with type 2 diabetes, 2023 Type: rct Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/37385280/ ### 11. Phase 2a trial of retatrutide for fatty liver disease, 2024 Type: rct Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/38858523/ ### 12. TRANSCEND-T2D-1: phase 3 trial of retatrutide in type 2 diabetes, 2026 Type: rct Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/42250575/ ### 13. TRIUMPH-2: phase 3 trial of retatrutide in obesity with type 2 diabetes, 2026 Type: rct Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/42810372/ ### 14. Review of trials of retatrutide for obesity, 2025 Type: systematic-review Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/39817343/ ### 15. CBS News: the maker sues sellers of its experimental weight-loss drug, August 2026 Type: reference Tier: established-news Source: https://www.cbsnews.com/news/eli-lilly-lawsuits-weight-loss-drug/ ### 16. CBS News: lab tests of products sold as retatrutide, October 2026 Type: reference Tier: established-news Source: https://www.cbsnews.com/news/tested-experimental-weight-loss-drug-results/ Last verified: 2026-10-26. Sources: - https://clinicaltrials.gov/api/int/studies?query.intr=retatrutide&filter.overallStatus=RECRUITING,NOT_YET_RECRUITING&limit=50&fields=NCTId,BriefTitle,OfficialTitle,OverallStatus,Phase,LeadSponsorName,Condition,InterventionName,LocationState,LocationCountry,BriefSummary,StartDate,LastUpdatePostDate - https://clinicaltrials.gov/api/v2/studies?query.intr=retatrutide+OR+LY3437943&filter.overallStatus=RECRUITING%2CNOT_YET_RECRUITING&pageSize=50&sort=StartDate%3Adesc&countTotal=true&fields=NCTId%2CBriefTitle%2COverallStatus%2CPhase%2CLeadSponsorName%2CStartDate%2CLocationCountry%2CLocationState - https://peptideindex.ai/methodology#evidence-grade - https://peptideindex.ai/methodology#short-answer - https://pubmed.ncbi.nlm.nih.gov/37366315/ - https://pubmed.ncbi.nlm.nih.gov/42810372/ - https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss [^1]: FDA: concerns with unapproved GLP-1 drugs used for weight loss, updated 1 October 2026 https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss [^2]: FDA warning letter to an online seller of research-use peptides, 10 December 2024 https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/prime-vitality-inc-dba-prime-peptides-695156-12102024 [^3]: FDA warning letter on compounded retatrutide, 9 September 2025 https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/genlabmeds-713650-09092025 [^4]: FDA warning letter on compounded retatrutide, 9 September 2025, second business https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/medclub-dr-jenn-712126-09092025 [^5]: FDA warning letter to an online seller of research-use retatrutide, 31 March 2026 https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/gram-peptides-721806-03312026 [^6]: FDA warning letter to an online seller of research-use peptides, 24 August 2026 https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/peak-performance-peptides-735127-08242026 [^7]: ClinicalTrials.gov: recruiting and not yet recruiting studies of retatrutide https://clinicaltrials.gov/api/int/studies?query.intr=retatrutide&filter.overallStatus=RECRUITING,NOT_YET_RECRUITING&limit=50&fields=NCTId,BriefTitle,OfficialTitle,OverallStatus,Phase,LeadSponsorName,Condition,InterventionName,LocationState,LocationCountry,BriefSummary,StartDate,LastUpdatePostDate [^8]: ArentFox Schiff: research-use labels are not a legal strategy, 18 September 2026 https://www.afslaw.com/perspectives/alerts/ruo-ined-five-peptide-vendors-learn-research-use-only-not-legal-strategy [^9]: Phase 2 trial of retatrutide in adults with obesity, 2023 https://pubmed.ncbi.nlm.nih.gov/37366315/ [^10]: Phase 2 trial of retatrutide in adults with type 2 diabetes, 2023 https://pubmed.ncbi.nlm.nih.gov/37385280/ [^11]: Phase 2a trial of retatrutide for fatty liver disease, 2024 https://pubmed.ncbi.nlm.nih.gov/38858523/ [^12]: TRANSCEND-T2D-1: phase 3 trial of retatrutide in type 2 diabetes, 2026 https://pubmed.ncbi.nlm.nih.gov/42250575/ [^13]: TRIUMPH-2: phase 3 trial of retatrutide in obesity with type 2 diabetes, 2026 https://pubmed.ncbi.nlm.nih.gov/42810372/ [^14]: Review of trials of retatrutide for obesity, 2025 https://pubmed.ncbi.nlm.nih.gov/39817343/ [^15]: CBS News: the maker sues sellers of its experimental weight-loss drug, August 2026 https://www.cbsnews.com/news/eli-lilly-lawsuits-weight-loss-drug/ [^16]: CBS News: lab tests of products sold as retatrutide, October 2026 https://www.cbsnews.com/news/tested-experimental-weight-loss-drug-results/