Retatrutide Benefits: 11 Measured Effects Beyond the Scale
Retatrutide benefits from the trials: 28.3% weight loss plus less knee pain, milder sleep apnea and lower A1C. See which are proven and which are still hopes.
On this page
- What does retatrutide target?
- How much weight people lost in the trials
- 11 retatrutide benefits measured beyond the scale
- What does retatrutide help with, condition by condition
- Heart and kidney benefits are still unproven
- Benefits people claim that no trial has measured
- What the benefits cost
- Can you get these benefits now?
The main retatrutide benefits are large weight loss and the health gains that ride along with it. In TRIUMPH-1, people on the 12 mg dose lost 28.3% of their body weight on average over 80 weeks, and other Phase 3 trials showed less knee pain, milder sleep apnea and lower blood sugar. Retatrutide is still in Phase 3 trials, so every number on this page comes from a study, not from a prescription.
Key takeaways
- Weight loss drives almost every other benefit, and it was smaller in people with type 2 diabetes: 20.8% on 12 mg in TRIUMPH-2 against 28.3% in TRIUMPH-1.
- Knee pain fell by about three quarters in TRIUMPH-4, but it also fell by 40.3% on placebo, which is the fairer number to compare against.
- Blood pressure and an inflammation marker both dropped, yet TRIUMPH-3 did not show fewer heart attacks, strokes or heart deaths.
- The kidney and liver results come from small Phase 2 studies that measured markers, not disease outcomes.
- Muscle gain, faster metabolism and longevity are online claims that no retatrutide trial in people has shown.
Most of what follows depends on how much weight people lost. Where a benefit has only been measured as a blood marker, or only in a small Phase 2 analysis, we say so right next to the number.
What does retatrutide target?
Three hormone receptors. Retatrutide is a single molecule that switches on the body's receptors for GIP (glucose-dependent insulinotropic polypeptide), GLP-1 (glucagon-like peptide-1) and glucagon, Lilly says. Semaglutide acts on GLP-1 alone and tirzepatide on GIP and GLP-1, which is why users started calling retatrutide GLP-3.
Which hormone receptors each drug acts on
Retatrutide adds glucagon to the two receptors tirzepatide already targets
| Drug | GIP | GLP-1 | Glucagon |
|---|---|---|---|
| SemaglutideOzempic, Wegovy | No | Yes | No |
| TirzepatideMounjaro, Zepbound | Yes | Yes | No |
| RetatrutideInvestigational | Yes | Yes | Yes |
The first two receptors are the pair tirzepatide already uses. Tirzepatide's label says it cuts how many calories people eat, likely by acting on appetite, and raises insulin release when blood sugar is up. That's class evidence from tirzepatide, not retatrutide.
Glucagon is the new part. In the Phase 2 liver study in Nature Medicine, the authors suggest retatrutide's bigger liver fat drop, compared with GLP-1 drugs and tirzepatide, may come from the extra weight loss, from glucagon acting directly on the liver, or both. The popular claim that retatrutide makes you burn more calories at rest hasn't been shown in people yet: a Lilly study that measured calorie intake and energy use (NCT06313528) finished in August 2025 and, as of September 2026, has posted no results. The full mechanism lives on our page about how retatrutide works.
How much weight people lost in the trials
Weight loss is the headline, and it changes with who took part. Each figure below is the average for the top dose, compared with placebo, as Lilly or the journal reported it.
| Trial | Who took part | Length | Retatrutide 12 mg | Placebo |
|---|---|---|---|---|
| Phase 2 (NEJM, 2023) | 338 adults with obesity or overweight | 48 weeks | -24.2% | -2.1% |
| TRIUMPH-1 | 2,339 adults with obesity or overweight, no diabetes | 80 weeks | -28.3% | -2.2% |
| TRIUMPH-2 | 1,152 adults with obesity or overweight and type 2 diabetes | 80 weeks | -20.8% | -4.0% |
| TRIUMPH-3 | 1,949 adults with a BMI of 35 or more and heart disease | 80 weeks | -22.6% | -3.2% |
| TRIUMPH-4 | 445 adults with obesity or overweight and knee osteoarthritis | 68 weeks | -28.7% | -2.1% |
In TRIUMPH-1, almost half the people on 12 mg (45.3%) lost at least 30% of their weight, and 65.3% ended below a BMI of 30. A 104-week extension kept going with people who started at a BMI of 35 or more, and those first assigned to 12 mg averaged 30.3%.
Those are efficacy estimates, which assume everyone stayed on treatment. Counting everyone randomized, including people who stopped, the TRIUMPH-1 figure on 12 mg was 25.0%. Lilly's lower 4 mg dose, reached with one step up from 2 mg, produced 19.0%.
Average weight lost by dose in TRIUMPH-1
80 weeks, 2,339 adults with obesity or overweight (efficacy estimand)
Our read: the other benefits track weight lost, so if you have type 2 diabetes, TRIUMPH-2's 20.8% is a better guide to what to expect than the 28.3% headline.
11 retatrutide benefits measured beyond the scale
These are the other effects the trials measured, with the best reported result for each. The last column is our judgment of how far each result goes.
| # | Effect | Best result | Trial and time point | How solid |
|---|---|---|---|---|
| 1 | Smaller waist | 24.1 cm (9.5 in) less | TRIUMPH-1, 12 mg, 80 weeks | Phase 3; placebo 3.6 cm less |
| 2 | Less body fat | Fat mass down 26.1% on 8 mg | Phase 2 body scan study, type 2 diabetes, 36 weeks | Phase 2, 103 people with both scans; placebo 4.5% |
| 3 | Lower A1C | Down 2.0% from 7.9% on 9 mg | TRANSCEND-T2D-1, 40 weeks | Phase 3 primary endpoint |
| 4 | Less knee pain, better function | Pain score down 4.5 points (75.8%) on 9 mg; function score down 73.7% on 12 mg | TRIUMPH-4, 68 weeks | Phase 3 primary endpoint; percentages post hoc |
| 5 | Milder sleep apnea | Up to 36.1 fewer breathing pauses per hour (60.6%) | TRIUMPH-1 sleep apnea group, 80 weeks | Phase 3 primary endpoint |
| 6 | Less liver fat | Down 82.4% on 12 mg | Phase 2 liver study, 24 weeks | Phase 2, 98 people, MRI only |
| 7 | Lower triglycerides | Down up to 41.0% | TRIUMPH-1, 80 weeks | Phase 3; no placebo figure published |
| 8 | Lower non-HDL cholesterol | Down up to 24.2% | TRIUMPH-1, 80 weeks | Phase 3; no placebo figure published |
| 9 | Lower systolic blood pressure | Down 14.0 mmHg on 12 mg | TRIUMPH-4, 68 weeks | Phase 3 secondary; no placebo figure published |
| 10 | Less inflammation (hsCRP) | Down 51.2% on 12 mg | TRIUMPH-3, 80 weeks | Phase 3; no placebo figure published |
| 11 | Less protein in the urine | Down 31.5% vs placebo on 12 mg | Phase 2 obesity trial, 48 weeks | Post hoc exploratory analysis |
Placebo groups improved too, sometimes a lot. In TRIUMPH-4, knee pain fell 40.3% on placebo, so the gap retatrutide added was about 35 percentage points, still large. In the Phase 2 body scan study, lean mass made up about the same share of weight lost as with other obesity drugs. That eases one common worry, though it doesn't make retatrutide a muscle builder.
What does retatrutide help with, condition by condition
Lilly says TRIUMPH-2 and TRIUMPH-3 complete the data it needs to file retatrutide for obesity and for two complications, knee osteoarthritis pain and sleep apnea.
Chronic low back pain is next. TRIUMPH-7, with about 586 people, lists September 2027 as the estimated date for its main results.
Knee osteoarthritis pain
TRIUMPH-4 enrolled people with knee osteoarthritis and a BMI of 27 or more. On the WOMAC pain scale, which runs from 0 to 10, scores started at 6.0 and fell by 4.5 points on 9 mg. By week 68, 14.1% of people on 9 mg and 12.0% on 12 mg were completely free of knee pain, against 4.2% on placebo. That's about 1 in 7 on 9 mg, from a post hoc analysis.
Sleep apnea
People in TRIUMPH-1's sleep apnea group started at 58.6 breathing pauses or shallow breaths per hour of sleep (the apnea-hypopnea index). Retatrutide cut that by up to 36.1 an hour. Lilly hasn't said how many people could stop using a CPAP machine, and we couldn't find it published.
Type 2 diabetes
In TRANSCEND-T2D-1, 537 adults who hadn't taken diabetes medicines for at least 90 days started at an A1C of 7.9%. Up to 90% reached an A1C below 7.0%, and up to 46% got below 5.7%, the non-diabetic range. The 2023 Phase 2 diabetes trial in The Lancet reported no severe low blood sugar. In tirzepatide's type 2 diabetes weight trial, low blood sugar hit 10.3% of people who also took a sulfonylurea, against 2.1% who didn't. That's class evidence, but if you take insulin or a sulfonylurea, ask your doctor how those doses would change.
Fatty liver
In a 98-person Phase 2 substudy, 86% of people on 12 mg reached normal liver fat by week 24. The study took no biopsies, so it shows fat leaving the liver, not scarring healing. Our retatrutide fatty liver page covers what that does and doesn't prove.
Heart and kidney benefits are still unproven
The risk factors moved the right way. Heart outcomes haven't, yet. TRIUMPH-3 enrolled 1,949 people with obesity and established heart disease, and major cardiovascular events were rarer than expected in both groups. There were 27 heart attacks, strokes or cardiovascular deaths on retatrutide and 23 on placebo, a hazard ratio of 1.12 with a 95% confidence range of 0.64 to 1.96. That range is too wide to call it good or bad. A broader count that also took in heart failure events, procedures to reopen heart arteries and deaths from any cause went 44 to 52 in retatrutide's favor (hazard ratio 0.82, range 0.55 to 1.22), and that range is just as wide.
A dedicated trial (NCT06383390) aims to answer it. It plans to enroll about 10,000 adults with a BMI of 27 or more and heart disease, kidney disease or both, and lists February 2029 as its estimated date for main results. It also tracks kidney failure and large drops in kidney function.
The kidney signal so far is a marker. In a 2025 analysis of both Phase 2 trials, 12 mg cut protein in the urine (albumin) by 31.5% against placebo at 48 weeks in people with obesity and by 37.0% at 36 weeks in people with type 2 diabetes. Most people started with normal albumin levels, so the drop in absolute terms was modest. The authors call every result exploratory because neither trial was built to study kidneys.
Our read: lower blood pressure and hsCRP make a heart benefit plausible, but TRIUMPH-3's 27 versus 23 events show why nobody can claim one before the outcomes trial reports.
Benefits people claim that no trial has measured
People on r/Retatrutide trade threads about "hidden benefits" beyond the scale. Those are user reports, not studies, and none of the claims below has a retatrutide trial result behind it.
| Claim you'll see online | What the evidence says |
|---|---|
| It builds or protects muscle | Lean mass still fell; its share of weight lost matched other obesity drugs in one Phase 2 scan study |
| It speeds up your metabolism | Not measured in people in any published study; the energy use trial has no posted results |
| It slows aging or extends life | No retatrutide trial has looked |
| It curbs alcohol or other cravings | No retatrutide trial has reported on it |
| It gives you more energy | Not a trial endpoint in any published retatrutide study |
If muscle is your worry, our page on retatrutide and muscle loss looks at the body composition data in detail.
What the benefits cost
Every benefit above came with side effects, mostly in the gut and mostly during dose increases. In TRIUMPH-1, 42.4% of people on 12 mg had nausea, about 4 in 10, against 14.8% on placebo. Vomiting hit 25.3% against 4.8%.
Burning, tingling or oversensitive skin (dysesthesia) is the one people don't expect. It affected 12.5% on 12 mg in TRIUMPH-1 and 20.9% in TRIUMPH-4, against under 1% on placebo, and was mostly mild to moderate. In the Phase 2 obesity trial, heart rate rose with dose, peaked at 24 weeks and eased after that.
Stopping for side effects was more common on higher doses: 11.3% on 12 mg in TRIUMPH-1 against 4.9% on placebo, and 4.1% on 4 mg. The full list, with how long each lasts, is on our retatrutide side effects page.
Get medical help now
Severe belly pain that won't go away, sometimes spreading to the back, can signal pancreatitis on drugs in this class. Pain in the upper belly, fever, yellow skin or eyes, or pale stools can point to a gallbladder problem; tirzepatide's label lists both. Get help too for vomiting you can't keep fluids down through, swelling of the face or throat or trouble breathing, or shakiness and sweating if you also take insulin or a sulfonylurea.Can you get these benefits now?
Legally, only through Lilly. The company says retatrutide is legally available only to people in its clinical trials, and it also lists a pre-approval expanded access program (NCT07629401) that a doctor can ask Lilly about for adults with a BMI of 35 or more and serious obesity complications who can't join a trial. Lilly adds that retatrutide "cannot be legally sold or marketed for human use." As of September 2026 no approved version exists, and Lilly plans to send the FDA a Biologics License Application (BLA) in the first quarter of 2027.
That leaves a big gap between the trial product and the vials sold online as reta. If you're weighing retatrutide for sale listings, none of them is the drug behind the numbers on this page, and there's no way to check what a given vial holds or how much. On June 19, 2026, the Victoria Department of Health in Australia reported six cases of acute liver injury in people using unapproved products labelled retatrutide and said a contaminant may be to blame.
Trials are the legal route, but few are open. As of September 2026, ClinicalTrials.gov lists one Lilly retatrutide trial still recruiting, SYNERGY-Outcomes, for adults with fatty liver disease at higher risk of liver complications. Our retatrutide clinical trials guide explains how to check whether you qualify.
Frequently asked questions
What does retatrutide do to your body?
It switches on three hormone receptors, GIP, GLP-1 and glucagon, which cut appetite and lower blood sugar. In trials that led to large weight loss, up to 28.3% on average over 80 weeks in TRIUMPH-1, along with a smaller waist, lower blood pressure and triglycerides, and less liver fat. It also raised heart rate in the Phase 2 trial, and in TRIUMPH-1 about 4 in 10 people on the top dose had nausea.
What does retatrutide target?
The receptors for three gut and pancreas hormones: glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and glucagon. Tirzepatide targets the first two and semaglutide only GLP-1. The glucagon receptor is why people call retatrutide a triple agonist or GLP-3.
What does reta help with besides weight loss?
In Phase 3 trials it reduced knee osteoarthritis pain, the number of breathing pauses in sleep apnea and A1C in type 2 diabetes. It also lowered triglycerides, non-HDL cholesterol, systolic blood pressure and hsCRP, a blood marker of inflammation. Smaller Phase 2 studies found less liver fat and less protein in the urine.
Does retatrutide protect your heart?
That hasn't been shown. In TRIUMPH-3, among people with obesity and heart disease, there were 27 heart attacks, strokes or cardiovascular deaths on retatrutide and 23 on placebo, and the trial was too small to settle the question. A 10,000-person outcomes trial lists February 2029 as its estimated date for main results.
Does retatrutide build muscle?
No trial has shown that. In a Phase 2 body scan study of people with type 2 diabetes, fat mass fell by up to 26.1%, and the authors say the share of weight lost as lean mass was similar to other obesity treatments. People still lost some lean mass, which is why protein and strength training come up so often.
Do products sold online as reta give the same benefits?
Nobody can say. Every benefit on this page comes from Lilly's trial product, and Lilly says retatrutide cannot be legally sold or marketed for human use. In June 2026, health officials in Victoria, Australia linked six cases of acute liver injury to unapproved products labelled retatrutide.
Sources
- Lilly's triple agonist, retatrutide, delivered powerful weight loss in pivotal Phase 3 obesity trial. Eli Lilly and Company (PR Newswire), 2026. prnewswire.com
- Lilly's triple agonist, retatrutide, drove substantial improvements in weight, A1C, knee osteoarthritis pain, and obstructive sleep apnea. Eli Lilly and Company (PR Newswire), 2026. prnewswire.com
- Lilly's triple agonist, retatrutide, demonstrated significant reductions in A1C and weight in first Phase 3 trial for treatment of type 2 diabetes. Eli Lilly and Company (PR Newswire), 2026. prnewswire.com
- Zepbound (tirzepatide) injection: prescribing information. Eli Lilly and Company, 2026. pi.lilly.com
- Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial. Nature Medicine, 2024. doi.org
- A Randomized, Double-Blind, Phase 1 Study to Investigate the Effect of LY3437943 Versus Placebo on Calorie Intake and Energy Expenditure in Participants With Obesity Under Calorie Restriction (NCT06313528). ClinicalTrials.gov, 2025. clinicaltrials.gov
- Triple-Hormone-Receptor Agonist Retatrutide for Obesity: A Phase 2 Trial. New England Journal of Medicine, 2023. nejm.org
- Lilly's triple agonist, retatrutide, successful in two additional Phase 3 obesity trials, delivering significant improvements in weight and A1C. Eli Lilly and Company (PR Newswire), 2026. prnewswire.com
- Lilly's triple agonist, retatrutide, delivered weight loss of up to an average of 71.2 lbs along with substantial relief from osteoarthritis pain in first successful Phase 3 trial. Eli Lilly and Company (PR Newswire), 2025. prnewswire.com
- Effects of retatrutide on body composition in people with type 2 diabetes: a substudy of a phase 2, double-blind, parallel-group, placebo-controlled, randomised trial. The Lancet Diabetes & Endocrinology, 2025. doi.org
- The Effect of Retatrutide on Kidney Parameters in Participants With Type 2 Diabetes Mellitus and/or Obesity. Kidney International Reports, 2025. pmc.ncbi.nlm.nih.gov
- Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA. The Lancet, 2023. doi.org
- A Phase 3 Study to Investigate the Effect of Retatrutide on the Incidence of Major Adverse Cardiovascular Events and Major Adverse Kidney Events (NCT06383390). ClinicalTrials.gov, 2024. clinicaltrials.gov
- A Study of Retatrutide (LY3437943) in Participants Who Have Obesity or Overweight and Chronic Low Back Pain (TRIUMPH-7, NCT07035093). ClinicalTrials.gov, 2025. clinicaltrials.gov
- A Master Protocol of Multiple Agents in Adults With Metabolic Dysfunction-Associated Steatotic Liver Disease (SYNERGY-Outcomes, NCT07165028). ClinicalTrials.gov, 2025. clinicaltrials.gov
- Pre-approval Expanded Access of Retatrutide (LY3437943), NCT07629401. ClinicalTrials.gov, 2026. clinicaltrials.gov
- Toxicity linked to unapproved peptide product labelled Retatrutide. Victoria Department of Health, 2026. health.vic.gov.au
Dr. Juan Pablo Frías, MD
Physician-Scientist & Clinical Trialist • Endocrinology, Diabetes & Metabolism
Dr. Frías earned his M.D. from Vanderbilt University School of Medicine and completed his endocrinology fellowship at UC San Diego. A principal investigator on landmark incretin trials (including retatrutide, tirzepatide and semaglutide), he reviews all guides on Retatrutide360 for clinical accuracy, dosing safety and evidence fidelity.
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Retatrutide Weight Loss Results
Retatrutide weight loss averaged 19.0% to 28.3% over 80 weeks in TRIUMPH-1. See every trial by dose, who lost less, and what an average can't tell you.
Retatrutide Side Effects
Retatrutide side effects by dose from Lilly's Phase 3 trials: nausea in up to 43.2%, skin sensitivity, a faster pulse, rare risks, and what makes them easier.
GLP-3 (Retatrutide)
GLP-3 is a nickname for retatrutide, Lilly's triple agonist. What GLP-3 RT labels mean, the 28.3% trial weight loss, side effects and when approval could come.
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