Retatrutide is an investigational once-weekly drug from Eli Lilly that acts on GIP, GLP-1 and glucagon receptors and has not been approved by any regulator [1] [3].
At a glance
No regulator has approved retatrutide, and FDA says it cannot be compounded [1] [2].
Is retatrutide FDA approved?Lilly plans to file with FDA in the first quarter of 2027; no release date exists [4].
When will retatrutide be available?Nausea reached 42.4% on the 12 mg dose in TRIUMPH-1, vs 14.8% on placebo [3].
Retatrutide side effects in the trialsThere is no legal price; Zepbound self-pay starts at $299 a month [8].
How much does retatrutide cost?
Legal status of Retatrutide
Not approved: trials onlyRetatrutide is an investigational drug that no regulator anywhere has approved [1]. FDA says it cannot be used in compounding [2].
- FDA status
- Lilly says no medicine containing retatrutide has been approved for human use by any regulator in the world [1]. FDA says retatrutide cannot be used in compounding under federal law [2]. FDA has warned sellers of "research purposes" GLP-1 products, including retatrutide [2].
- Advisory committee
- Not applicable. Retatrutide is an investigational drug, not a compounding substance [2].
- FDA-approved products
- None. No retatrutide medicine is approved [1].
- Sports (WADA)
- Retatrutide is not named on the 2026 list [16]. The list's S0 class covers substances with no approval by any government health authority for human use [16], and retatrutide has no approval anywhere [1]. Whether that class covers it is a judgment call, so athletes should ask their anti-doping agency before use.
- What happens next
- Lilly must file for approval and FDA must approve it. Lilly plans to submit a Biologics License Application to FDA in the first quarter of 2027 [4]. FDA review would follow, so a legal prescription is not possible before then.
Checked against FDA sources on . We update this box when FDA acts. Report a change: [email protected].
Is retatrutide FDA approved?
No. Lilly describes retatrutide as "an investigational, once-weekly, triple hormone receptor agonist" that acts on the GIP, GLP-1 and glucagon receptors [3]. It is in Phase 3 trials, and Lilly says "no medicine containing retatrutide has yet been approved for human use by any regulatory agency in the world" [1]. FDA says plainly that "retatrutide and cagrilintide cannot be used in compounding under federal law," and that it has not been found safe and effective for any condition [2].
That means no US doctor can legally prescribe it outside a clinical trial, and no pharmacy can legally fill or compound it. For the approved GLP-1 drugs that exist now, see our GLP-1 cost guide.
When will retatrutide be available?
Lilly said on July 23, 2026 that it plans to submit a Biologics License Application for retatrutide to FDA in the first quarter of 2027, after it completes its manufacturing data package [4]. FDA review comes after the filing, and FDA must approve the drug before any pharmacy can fill a prescription. There is no approval date or release date yet. Any site that gives one is guessing.
Retatrutide trial results
Lilly reports two kinds of averages. The efficacy estimand estimates the result if everyone had kept taking the drug as assigned. The treatment-regimen estimand counts everyone who started, including people who stopped. In TRIUMPH-1, the efficacy figures were the larger ones. The table uses the efficacy estimand because it is the one Lilly reported for every trial.
| Trial | Who was in it | Length | Placebo | 4 mg group | 9 mg group | 12 mg group | Source |
|---|---|---|---|---|---|---|---|
| TRIUMPH-1 | 2,339 adults with obesity or overweight and at least one weight-related condition, without diabetes | 80 weeks | -2.2% | -19.0% | -25.9% | -28.3% | [3] |
| TRIUMPH-2 | 1,152 adults with obesity or overweight and type 2 diabetes | 80 weeks | -4.0% | -12.7% | -19.1% | -20.8% | [4] |
| TRIUMPH-3 | 1,949 adults with severe obesity and established cardiovascular disease | 80 weeks | -3.2% | Not reported | -21.6% | -22.6% | [4] |
| TRIUMPH-4 | 445 adults with obesity or overweight and knee osteoarthritis, without diabetes | 68 weeks | -2.1% | Not reported | -26.4% | -28.7% | [5] |
In TRIUMPH-1, the treatment-regimen averages were -17.6%, -23.7% and -25.0% for the 4, 9 and 12 mg groups, against -3.9% on placebo. Lilly also reported a 104-week extension in 532 people with a BMI of 35 or higher who finished the main trial and tolerated their dose, with average loss of up to 30.3% (efficacy estimand) [3]. Lilly said more detailed results "will be presented at future medical meetings and published in peer-reviewed journals" [3].
- TRIUMPH-2 (type 2 diabetes): A1C fell by up to 1.6% [4].
- TRIUMPH-3 (heart disease): major heart events were less frequent than expected in all groups, and the trial did not show a clear difference: 44 events on retatrutide vs 52 on placebo for the main five-part measure (hazard ratio 0.82, 95% CI 0.55 to 1.22) [4].
- TRIUMPH-4 (knee osteoarthritis): at 68 weeks, people on the 12 mg dose lost an average of 71.2 pounds, and WOMAC knee pain scores fell 74.3% on 12 mg and 75.8% on 9 mg, vs 40.3% on placebo (efficacy estimand) [5].
Retatrutide side effects in the trials
The most common side effects were stomach-related, and they rose with dose. TRIUMPH-1 had the largest group of people without diabetes:
| Side effect | Placebo | 4 mg group | 9 mg group | 12 mg group |
|---|---|---|---|---|
| Nausea | 14.8% | 28.6% | 38.4% | 42.4% |
| Vomiting | 4.8% | 10.6% | 22.8% | 25.3% |
| Dysesthesia (abnormal skin sensations) | 0.9% | 5.1% | 12.3% | 12.5% |
| Stopped the drug because of side effects | 4.9% | 4.1% | 6.9% | 11.3% |
Other trials showed the same pattern. In TRIUMPH-2, nausea reached up to 28.0% vs 8.0% on placebo, and dysesthesia up to 7.3% [4]. In TRIUMPH-3, 9.8% and 13.5% of people on the 9 mg and 12 mg doses stopped because of side effects, vs 4.8% on placebo [4]. In TRIUMPH-4, dysesthesia was reported by 8.8% and 20.9% on 9 mg and 12 mg vs 0.7% on placebo, and 12.2% and 18.2% stopped because of side effects, vs 4.0% on placebo. Lilly said the dysesthesia events "were generally mild and rarely led to treatment discontinuation" [5].
These numbers come from supervised trials
Trial participants got drug made by Lilly and were monitored by study doctors. Products sold online as retatrutide are not the same product. If you have used one and have severe stomach pain that will not go away or signs of an allergic reaction such as swelling of the face or throat or trouble breathing, get medical care. Call 911 in an emergency.
Is retatrutide safe?
No regulator has judged it safe, and FDA says it has not been found safe and effective for any condition [2]. The trial data above describe Lilly's drug in monitored settings. The products people actually buy online are a separate problem. Pharmaphorum reported that analysis of seized counterfeit samples found doses ranging from zero to overdoses and different active ingredients such as insulin, that many are thought to be made in non-sterile conditions, and that there have been reports of serious side effects, including liver failure, among people buying them this way [10]. FDA says the quality of research-labeled GLP-1s sold to consumers is unknown and may be harmful [2].
We cover those risks in full on our page on research-use-only GLP-1s and retatrutide.
How much does retatrutide cost?
Retatrutide has no legal price, because it cannot be legally sold or compounded in the US [1] [2]. We found no price announced by Lilly. Any price you see online is for a product sold outside the law, with unknown contents. What a legal, FDA-approved weight-loss drug costs today:
| Drug | Channel | Self-pay price | Conditions | Source |
|---|---|---|---|---|
| Zepbound (tirzepatide) | LillyDirect | $299 (2.5 mg), $399 (5 mg), $449 (7.5 to 15 mg) a month | $449 applies on first fill and on refills within 45 days; otherwise $499 (7.5 mg) or $699 (10 to 15 mg). LillyDirect counts a month as 28 days. Prescription required. | [8] |
| Wegovy pen (semaglutide) | NovoCare Pharmacy | $349 a month, all standard doses | New self-pay patients pay $199 a month for the 0.25 mg and 0.5 mg pens for their first two fills, through Dec 31, 2026. Prescription required. | [9] |
Full price tables, including insurance and savings cards: Zepbound cost and Wegovy cost. For other peptides that can be prescribed legally, see the legal peptide price tracker and the peptide FDA status tracker, which lists retatrutide alongside BPC-157, tesamorelin and others.
How to get retatrutide legally
Legal options that exist today
- Wegovy: a different drug: an FDA-approved GLP-1 medicine for chronic weight management in people who meet its label criteria
- Zepbound: a different drug: FDA-approved tirzepatide for chronic weight management in people who meet its label criteria
Retatrutide vs tirzepatide
Retatrutide is made by Lilly, the same company that makes tirzepatide (Zepbound and Mounjaro). We found no head-to-head trial result comparing them. The table puts the main obesity trial for each drug side by side so you can see what each reported, not which works better.
| Retatrutide (TRIUMPH-1) | Tirzepatide (SURMOUNT-1) | |
|---|---|---|
| FDA status | Not approved anywhere [1] | FDA-approved as Zepbound for chronic weight management [6] |
| Who was in the trial | Adults with obesity or overweight and at least one weight-related condition, without diabetes [3] | Adults with obesity or overweight, without diabetes [6] |
| Trial length | 80 weeks [3] | 72 weeks [7] |
| Average weight change, highest dose | -28.3% on 12 mg (efficacy estimand) [3] | -20.9% on 15 mg [7] |
| Average weight change, placebo | -2.2% [3] | -3.1% [7] |
| Nausea, highest dose vs placebo | 42.4% vs 14.8% [3] | 28% vs 8% (label, two trials pooled, one in adults with type 2 diabetes) [6] |
| Stopped for side effects, highest dose vs placebo | 11.3% vs 4.9% [3] | 6.2% vs 2.6% [7] |
Tirzepatide can be prescribed today. See our tirzepatide guide, Zepbound results and Wegovy vs Zepbound.
Research-use-only retatrutide and enforcement
FDA has sent a series of warning letters to sellers of retatrutide labeled for research. Summit Research Peptides got one dated Dec 10, 2024 [13]. Letters dated March 31, 2026 to Prime Sciences and Mile High Compounds cited retatrutide sold under coded names such as "GLP1-R" and "GLP-3 RT" [14] [11]. A letter dated Aug 24, 2026 to Peptide Partners cited "GLP-3 Reta" and rejected its "for research use only" label [12]. Our FDA warning letter list tracks them.
On Aug 12, 2026, Lilly announced six lawsuits against companies selling retatrutide, filed in federal courts in California and Texas, and said it had made more than 200 referrals to FDA, the Justice Department, state attorneys general and licensing boards [1]. Lilly's statement: "What is being sold on the black market is not a medicine" [1]. We could not confirm the current status of each suit. In April 2026, federal prosecutors in Utah indicted a physician on charges that included receiving misbranded retatrutide from China; those are allegations, and he is presumed innocent [15].
What changed for retatrutide
Newest first.
- : FDA's page on unapproved GLP-1 drugs, updated on this date, says retatrutide cannot be used in compounding under federal law [2].
- : Lilly announced six lawsuits against retatrutide sellers [1].
- : Lilly said it plans to submit a Biologics License Application to FDA in the first quarter of 2027 [4].
- : Lilly reported topline results from its TRIUMPH-1 obesity trial [3].
How we check
Trial numbers come from Lilly's own results releases, and we say which estimand each number uses. Legal status comes from Lilly's statements and FDA's Oct 1, 2026 statement on unapproved GLP-1s. Alternative prices come from the makers' self-pay pages, checked Oct 17, 2026. We do not link to sellers. When Lilly files or FDA acts, the status box and this page change. Our method: editorial standards.
Questions people ask
Is retatrutide FDA approved?
When will retatrutide be available?
Not before FDA approves it, and Lilly has not filed yet. Lilly said on July 23, 2026 that it plans to submit a Biologics License Application in the first quarter of 2027 [4]. FDA review follows the filing, so there is no release date as of Oct 19, 2026.
How much does retatrutide cost?
There is no legal price. Retatrutide is not approved and cannot be compounded, so it cannot be legally sold in the US [1] [2], and we found no price announced by Lilly. For comparison, Zepbound costs $299 to $449 a month self-pay through LillyDirect, with the $449 price for 7.5 to 15 mg applying on the first fill and on refills within 45 days, as of Oct 17, 2026 [8].
What are the side effects of retatrutide?
In the 80-week TRIUMPH-1 trial, nausea affected 42.4% of people on the 12 mg dose vs 14.8% on placebo, vomiting 25.3% vs 4.8%, and dysesthesia (abnormal skin sensations) 12.5% vs 0.9%; 11.3% stopped because of side effects vs 4.9% [3].
How much weight do people lose on retatrutide?
In TRIUMPH-1, adults without diabetes on the 12 mg dose lost an average of 28.3% of body weight at 80 weeks, vs 2.2% on placebo, using Lilly's efficacy estimand; counting everyone who started, the figures were 25.0% and 3.9% [3]. These are trial averages from Lilly's announcement, not a promise for any person.
Is retatrutide better than tirzepatide?
No head-to-head result has been published in the sources we checked. In separate trials, retatrutide 12 mg averaged -28.3% at 80 weeks in TRIUMPH-1 [3] and tirzepatide 15 mg averaged -20.9% at 72 weeks in SURMOUNT-1 [7], but the trials differ in length and analysis method, so the numbers do not compare directly. Only tirzepatide is FDA-approved [6].
Is retatrutide safe?
Can a pharmacy compound retatrutide?
No. FDA's Oct 1, 2026 statement says "retatrutide and cagrilintide cannot be used in compounding under federal law" [2].
Is Lilly suing retatrutide sellers?
Yes. On Aug 12, 2026, Lilly announced six lawsuits against retatrutide sellers in federal courts in California and Texas and more than 200 referrals to regulators and law enforcement [1].
Sources
16 cited
- Lilly calls on online platforms, payment companies and regulators to act on illegal retatrutide sales. Eli Lilly and Company, Aug 12, 2026.
- FDA's concerns with unapproved GLP-1 drugs used for weight loss. FDA, Oct 1, 2026.
- Retatrutide TRIUMPH-1 topline results. Eli Lilly and Company, May 21, 2026.
- Retatrutide TRIUMPH-2 and TRIUMPH-3 results. Eli Lilly and Company, Jul 23, 2026.
- Retatrutide TRIUMPH-4 results. Eli Lilly and Company, Dec 11, 2025.
- Zepbound (tirzepatide) prescribing information. FDA, Apr 2026.
- SURMOUNT-1 trial (Jastreboff et al., NEJM 2022). New England Journal of Medicine (PubMed), Jun 4, 2022.
- Zepbound on LillyDirect: self-pay prices. Eli Lilly and Company (LillyDirect), Oct 17, 2026.
- Wegovy self-pay offer. Novo Nordisk (NovoCare), Oct 17, 2026.
- Lilly sues over illegal sales of obesity drug retatrutide. pharmaphorum, Aug 12, 2026.
- Warning letter: Mile High Compounds LLC. FDA, Mar 31, 2026.
- Warning letter: Peptide Partners LLC. FDA, Aug 24, 2026.
- Warning letter: Summit Research Peptides. FDA, Dec 10, 2024.
- Warning letter: Prime Sciences. FDA, Mar 31, 2026.
- Utah licensed osteopathic physician indicted for allegedly receiving misbranded drugs from China. U.S. Attorney's Office, District of Utah, Apr 2026.
- 2026 Prohibited List. World Anti-Doping Agency (copy hosted by Asia Rugby), Sep 2025.
This page is general information, not medical advice. Talk with a licensed clinician about your own care.