Research review · Updated October 28, 2026 · Sources checked October 19–28, 2026

Published July 17, 2026 · Updated October 28, 2026

Retatrutide: what the trials show, side effects, and the “food noise” question

Retatrutide is Eli Lilly’s investigational once-weekly shot that acts on three hormone receptors (GIP, GLP-1 and glucagon). It is not FDA approved.[1] Six phase 3 trials have now reported, including the first head-to-head, against Ozempic.[23] In the four longer obesity trials (68 to 80 weeks), average weight loss at the top dose ran from about 19% in people with type 2 diabetes to about 29%, depending on the trial and how it is counted, and Lilly plans to file for approval in the first quarter of 2027.[10] The side effects to know about are stomach problems, skin-sensation changes (dysesthesia) and, in some trials, low blood pressure.

Where retatrutide stands (October 2026)

• Not approved anywhere. Drugs@FDA lists no application.[1] Lilly says it is finishing the manufacturing (CMC) data package and plans to submit a Biologics License Application in Q1 2027, and that retatrutide “cannot be legally sold or marketed for human use.”[10]
• A regulatory fight is still open. FDA said again on October 2, 2026 that it considers retatrutide a drug rather than a biologic, part of an ongoing dispute with Lilly over which kind of application applies. It is not a rejection of the drug.[18]
• There is a legal access route, but it is narrow. Since June 5, 2026, Lilly has listed a single-patient expanded-access program for adults with a BMI of 35 or more, at least two serious obesity-related complications, no success on the highest available dose of an approved weight drug, and no way to join a trial.[16]

Phase 3 results so far

Lilly’s press releases lead with the “efficacy estimand,” an estimate of what happens if everyone stays on the drug. Journals lead with the “treatment-regimen” count, which includes everyone randomized, whether or not they stayed on it. That stricter number is closer to what a new patient should expect, so we show it where it has been published.[5][6][9][10]

All six trials were sponsored by Lilly. People with type 2 diabetes lost less weight, the same pattern seen with Wegovy; our TRIUMPH-2 teardown explains that gap and the two ways of counting. Our TRANSCEND-T2D-2 teardown covers the Ozempic comparison and what the topline release leaves out.

Sleep apnea and knee pain. TRIUMPH-1 also ran two smaller trials inside the main one. In 243 people with moderate-to-severe obstructive sleep apnea, breathing pauses and shallow-breathing events (the apnea-hypopnea index) fell by 34.3 an hour on 9 mg and 31.7 on 12 mg, versus 9.9 on placebo. In 574 people with knee osteoarthritis, pain on a 0-10 scale fell 3.5 points on 9 mg and 3.6 on 12 mg, versus 1.9 on placebo. Both gaps were statistically significant. These are the journal’s main “hybrid” estimates for the two sub-trials; counting everyone randomized gave similar results (apnea events down 34.3 and 32.1 versus 9.6).[5] Neither sub-trial compared retatrutide with Zepbound (tirzepatide), which the FDA approved for sleep apnea in December 2024, so they can’t say which drug works better for it. Update, October 22: the full sleep-apnea results were published in the NEJM on October 21 (Lilly-funded), covering those 243 people plus a second, 448-person sleep-apnea trial inside TRIUMPH-2 in people with type 2 diabetes. In that trial, apnea events fell 24.7 an hour on 9 mg and 25.4 on 12 mg, versus 10.3 on placebo, from a starting average of about 56; weight fell up to 18.5%, versus 5.6% on placebo. Our reading, comparing across trials rather than within one: the gap over placebo was smaller with diabetes (about 14 to 15 events an hour) than without it (about 22 to 24).

Does retatrutide get rid of “food noise”?

This is the question going around X this week, where users describe food as “just fuel,” no cravings, and sharper focus within weeks.[20] The plain answer: the drug clearly cuts hunger and the urge to overeat, but “food noise” itself has never been measured, and the focus claims are untested.

What the trials did measure. In the 338-person phase 2 obesity trial, people filled out the 51-item Eating Inventory at weeks 24 and 48. Hunger and “disinhibition” (losing control of eating when stressed or tempted) fell more on every retatrutide dose than on placebo. Deliberate restraint went up in every group, placebo included, with no difference between them. People who lost the most weight also reported the biggest drops in hunger and disinhibition.[11] A phase 2 trial in 275 adults with type 2 diabetes found the same thing on appetite rating scales at doses of 4 mg and up.[3][12] In exit interviews with 40 phase 2 participants, 31 of the 36 who got retatrutide said their eating changed within the first 8 weeks, and 25 described feeling happy.[13]

What is missing. These are exploratory, Lilly-run analyses of a few hundred people, and the p-values were not adjusted for multiple comparisons.[11] There is no standard scale for “food noise.” Lilly built a new eating questionnaire (the EBAQ) partly from those same interviews and validated it in a 120-person online survey, but we found no retatrutide trial results that use it yet.[14] We checked all 33 retatrutide studies registered on ClinicalTrials.gov: none lists focus, cognition, mood or depression as an outcome, and only one, an 85-person phase 1 study that finished in August 2025 with no results posted, lists appetite and calorie intake.[15] The only published retatrutide memory study we found was in diabetic rats.[19]

Appetite loss can also be a side effect. In TRIUMPH-2, “decreased appetite” was logged as an adverse event in 17.1% of people on 12 mg versus 4.5% on placebo.[10] If you want the broader question of whether these drugs dull pleasure beyond food, see our GLP-1 “joy” teardown.

About “within weeks.” Trial participants started at 2 mg and stepped up every four weeks.[10] In phase 2, the 12 mg group had lost 17.5% at 24 weeks and 24.2% at 48 weeks.[2] The big headline numbers took months.

Side effects

• Stomach problems, by far the most common. In TRIUMPH-1 at 12 mg: nausea 42.4% vs 14.8% on placebo, diarrhea 32.0% vs 13.5%, vomiting 25.3% vs 4.8%.[9]
• Dysesthesia (tingling, burning or odd skin sensations). 12.5% on 12 mg vs 0.9% on placebo in TRIUMPH-1; 7.3% vs 0.7% in TRIUMPH-2; 6.4% vs 1.3% in TRIUMPH-3. Lilly says most cases were mild to moderate and resolved during treatment.[9][10]
• Low blood pressure. 6% on 12 mg vs under 1% on placebo in TRIUMPH-2, worth knowing if you already take blood-pressure medicine.[6]
• Heart rate. In phase 2, heart rate rose with dose, peaked at 24 weeks and declined after that.[2]
• Quitting for side effects. 11.3% on 12 mg vs 4.9% on placebo in TRIUMPH-1, and 13.5% vs 4.8% in TRIUMPH-3.[9][10]
• Heart attacks and strokes: not settled. In TRIUMPH-3, which enrolled people with heart disease, there were 27 major cardiovascular events (heart death, heart attack or stroke) on retatrutide (9 mg and 12 mg pooled) and 23 on placebo (hazard ratio 1.12, 95% CI 0.64 to 1.96). That is too few events to show benefit or harm. A dedicated outcomes trial of about 10,000 people is still running.[10][15]

Gray-market retatrutide

Retatrutide is widely sold online as a “research peptide.” The first published lab test of those products, from Australia, analyzed three vials labelled 10 mg. All three contained retatrutide, but the amounts were 5.13 mg, 16.5 mg and 19.0 mg, or 51% to 190% of the label. Heavy metals were far below safety limits, but sterility and bacterial toxins were not tested.[17] That means a dose meant to be 2 mg could really be anywhere from about 1 mg to nearly 4 mg. None of the trial numbers above apply to these products. Our powder supply-chain teardown covers who makes the raw powder.

What’s new (October 2026)

October 21: a CBS News lab test. CBS News reported that it bought three products sold as retatrutide: two ordered from websites, which CBS said arrived without the buyer speaking to a health professional, and one vial bought over the counter at a corner store in Brooklyn, labelled “Research use only, not for human consumption.” According to CBS, a University of Iowa research scientist found both online samples consistent with a basic retatrutide standard he made, which CBS noted is not the same as the drug in Lilly’s trials. CBS did not report amount, purity or sterility results for those two. The corner-store sample “does not look anything like a peptide,” the scientist told CBS; he found phenylacetic acid, which he described as a filler, and a second University of Iowa test found 13 colonies of bacteria in it. Three products from one news investigation can’t show how common either result is. Lilly told CBS that “a single test is a snapshot, not a guarantee that the dose will be sterile or stable in two weeks, let alone that the next vial will be safe.”[21]

October 14: what Reddit users report. In JAMA Network Open, University of Pennsylvania researchers used AI tools to review 148,640 retatrutide-related Reddit posts and comments. They found 13,589 users describing current use, and 7,823 who described at least one classifiable symptom beyond weight loss or appetite suppression. Among those 7,823, the study authors reported increased appetite (17.1%), fatigue (15.2%), increased energy (12.4%), nausea (11.6%), insomnia (6.1%) and a faster heart rate (4.8%); vomiting was 2.6%. That differs from the trials, where stomach side effects were the most common.[2][22] The authors call their findings “hypothesis-generating” and say product identity, purity, dose and medical history “cannot be verified,” so the study can’t show how often these symptoms happen or that retatrutide caused them. People who post may also differ from other users.[22]

What is not known yet

We don’t yet know what happens over years of use or after stopping (a weight-maintenance trial is underway), whether retatrutide prevents heart attacks or kidney disease, or how it compares head-to-head with tirzepatide (Zepbound) and semaglutide; those trials are listed as active but not yet reported.[15] Every phase 3 result so far comes from the same sponsor.

Frequently asked questions

Is retatrutide FDA approved?

No. Retatrutide is investigational, and Drugs@FDA lists no approved application. Lilly says it plans to submit it to the FDA in the first quarter of 2027, after finishing its manufacturing data package, and that it cannot legally be sold or marketed for human use. [1][10]

When could retatrutide be available?

Lilly plans to file in Q1 2027, and approval can only come after FDA reviews that filing, so it will not be available as an approved drug in 2026. A separate dispute over whether FDA reviews it as a drug or a biologic is still unresolved. [10][18]

How much weight do people lose on retatrutide?

In Lilly's 80-week TRIUMPH-1 trial in people without diabetes, the 12 mg dose produced 25.0% average weight loss counting everyone randomized (28.3% in Lilly's on-drug estimate), versus 3.9% on placebo. People with type 2 diabetes lost less: 18.8% versus 5.1% in TRIUMPH-2. [5][6][9]

Does retatrutide stop food noise?

Lilly's phase 2 questionnaires found less hunger and less tendency to overeat on every retatrutide dose than on placebo, and most exit-interview participants said their eating changed within 8 weeks. But no trial has measured food noise itself, and none of the 33 registered retatrutide studies lists focus, cognition or mood as an outcome, so claims of sharper focus are untested. [11][13][15]

What is dysesthesia on retatrutide?

Dysesthesia means abnormal or unpleasant skin sensations such as tingling, burning or sensitivity. In TRIUMPH-1 it was reported by 12.5% of people on 12 mg versus 0.9% on placebo. Lilly says most cases were mild to moderate and resolved during treatment. [9][10]

Is gray-market retatrutide the same as the trial drug?

No. In the first published lab test of vials sold as retatrutide, three vials labelled 10 mg contained 5.1 mg, 16.5 mg and 19.0 mg. They did contain retatrutide, but the dose ranged from about half to nearly double the label, and sterility was not tested. In an October 2026 CBS News test, a vial sold as retatrutide at a Brooklyn corner store contained no peptide at all, and a lab grew bacteria from it. [17][21]

This page summarizes published research and regulatory documents. It is not medical advice and does not recommend using, sourcing, or dosing retatrutide, which is investigational and not FDA approved.