Retatrutide benefits: what the trials show beyond weight loss

What are the real retatrutide benefits, beyond the scale? Trials have now reported on blood sugar, liver fat, knee pain, sleep apnea, blood pressure and body fat. But retatrutide is not approved by the FDA or any other regulator, so none of these is an approved use [Lilly, Oct 28, 2026]. Each benefit below carries a grade that says how strong the evidence is.

We use four grades. A phase 3 paper is a large trial published in a peer-reviewed journal. A phase 3 press release means Lilly announced it, but no paper has checked it yet. A phase 2 or substudy result comes from a smaller, earlier trial. Being studied means a trial is running and nothing has been reported. Expected dates are the registry's own estimates.

What are retatrutide's benefits, and how strong is the evidence?

All of these trials were funded by Lilly. The figures in the table come from papers or the registry. The weight figure counts everyone assigned to the drug, including people who stopped [NEJM, Sep 29, 2026]. The fat-mass figure counts only scans taken while people were still on the drug [Lancet Diabetes Endocrinol, 2025]. Lilly's press-release figures assume everyone stayed on it, so they run larger, and we keep them out of the table. For weight, the retatrutide weight loss results guide sets out both kinds side by side.

Retatrutide for diabetes: what happened to blood sugar?

This is the best-tested benefit after weight. A1C is the standard measure of average blood sugar over the past few months. In TRANSCEND-T2D-1, 537 adults with type 2 diabetes took retatrutide or placebo on top of diet and exercise for 40 weeks [Lancet, Jun 6, 2026]. Starting from an average A1C of 7.9%, it fell 1.69, 1.86 and 1.94 points on 4, 9 and 12 mg, compared with 0.81 on placebo [Lancet, Jun 6, 2026]. No severe low blood sugar was reported [Lancet, Jun 6, 2026].

The earlier phase 2 diabetes trial pointed the same way. A1C fell 2.02 points on 12 mg at 24 weeks, compared with 0.01 on placebo [Lancet, 2023]. In TRIUMPH-2, a weight trial in people with diabetes, the paper says retatrutide was associated with improvements in glycaemic control [Lancet, Sep 29, 2026]. Lilly reported that up to 40.0% of people there reached an A1C below 5.7%, the normal range, on its stay-on-drug basis [Lilly, Sep 29, 2026]. Lilly notes that figure was not adjusted for multiple testing.

There is one head-to-head result. In TRANSCEND-T2D-2, A1C fell 2.2 points on retatrutide 9 mg and 12 mg over 80 weeks, compared with 1.8 on Ozempic 2 mg, on Lilly's stay-on-drug basis [Lilly, Oct 28, 2026]. That trial was open label, so people knew which drug they had. It is still only a press release, with no paper yet [Lilly, Oct 28, 2026]. The retatrutide vs semaglutide guide covers it in detail.

Does retatrutide help fatty liver?

The data so far are promising but early. A phase 2 substudy followed 98 people from the obesity trial who had fatty liver disease, with at least 10% of the liver made of fat [Nature Medicine, 2024]. At 24 weeks, liver fat fell by 82.4% on 12 mg, relative to where it started. On placebo it rose 0.3% [Nature Medicine, 2024]. And 86% of people on 12 mg reached a normal liver fat level, under 5%, compared with none on placebo [Nature Medicine, 2024].

Three cautions apply. The study measured fat by MRI, not scarring by biopsy. Standard liver blood tests and fibrosis scores did not change consistently versus placebo [Nature Medicine, 2024]. And it was small. A large phase 3 trial now tests whether retatrutide prevents serious liver events, and it is recruiting [ClinicalTrials.gov, NCT07165028]. The registry estimates its main data collection ends in August 2030 [ClinicalTrials.gov, NCT07165028]. For why the glucagon receptor may matter here, see how retatrutide works.

Does it ease knee pain and sleep apnea?

Yes, in two sets of phase 3 trials, both now peer reviewed. The figures below are the papers' main "hybrid" results, which handle people who stopped in a mixed way. The papers also give count-everyone results, with somewhat smaller gaps from placebo.

Knee osteoarthritis. TRIUMPH-4 enrolled 445 adults with obesity and painful knee osteoarthritis [NEJM, Nov 8, 2026]. On a 0-to-10 pain scale, scores fell 3.96 points on 9 mg and 3.74 on 12 mg over 68 weeks, compared with 2.12 on placebo [NEJM, Nov 8, 2026]. In a second group of 574 people inside TRIUMPH-1, pain fell 3.64 points on 12 mg over 80 weeks, compared with 1.87 on placebo [NEJM, Nov 8, 2026]. Lilly also reported that 14.1% on 9 mg were free of knee pain at 68 weeks, compared with 4.2% on placebo. That was an after-the-fact analysis [Lilly, Dec 11, 2025].

Sleep apnea. In 243 adults with moderate to severe sleep apnea and no diabetes, breathing pauses fell by 34.3 an hour on 9 mg over 80 weeks [NEJM, Oct 21, 2026]. On placebo they fell 9.9, from a starting average of 58.6 an hour [NEJM, Oct 21, 2026]. In 448 people with sleep apnea and type 2 diabetes, the drop was 25.4 on 12 mg, compared with 10.3 [NEJM, Oct 21, 2026]. Note that tirzepatide (Zepbound) is already approved to treat sleep apnea in adults with obesity [FDA label, Aug 2026]. Retatrutide is not.

Retatrutide and blood pressure, cholesterol and waist size

These numbers come from Lilly press releases, so they are graded lower. They also use Lilly's stay-on-drug basis. In TRIUMPH-1, systolic blood pressure fell by up to 12.3 mmHg over 80 weeks. Triglycerides fell up to 41.0%, non-HDL cholesterol up to 24.2%, and waist size up to 24.1 cm [Lilly, Jun 6, 2026].

Other trials showed the same direction. At the top dose, systolic pressure fell 10.8 mmHg in TRIUMPH-2 [Lilly, Sep 29, 2026], 9.3 in TRIUMPH-3 [Lilly, Jul 23, 2026] and 14.0 in TRIUMPH-4 [Lilly, Dec 11, 2025]. A peer-reviewed post hoc look at the phase 2 trials, mostly by Lilly scientists, found similar falls. Non-HDL cholesterol dropped up to 26.9% against placebo, along with other blood markers linked to heart disease [Diabetes Obes Metab, Aug 2026].

There's a flip side. In TRIUMPH-2, low blood pressure was reported in 6% of people on 12 mg, compared with under 1% on placebo [Lancet, Sep 29, 2026]. And lower blood pressure or cholesterol is a risk marker, not proof of fewer heart attacks. The retatrutide side effects guide covers the downsides.

Does retatrutide cause muscle loss?

People ask because fast weight loss can take muscle along with fat. The one published body-scan study comes from the phase 2 diabetes trial [Lancet Diabetes Endocrinol, 2025]. Using DXA scans, it found total fat mass fell 23.2% on 12 mg over 36 weeks, compared with 4.5% on placebo [Lancet Diabetes Endocrinol, 2025].

On lean mass, the authors wrote: The proportion of lean mass loss to weight loss was similar to other obesity treatments. [Lancet Diabetes Endocrinol, 2025] That's mildly reassuring, with limits. Only 103 people had both scans, all had type 2 diabetes, and the study was run by Lilly scientists [Lancet Diabetes Endocrinol, 2025]. Lean mass on a DXA scan also isn't the same as muscle strength, which no reported trial measured.

A larger scan study, about 100 people inside TRIUMPH-3, is part of that trial's design [Diabetes Obes Metab, 2025]. No result from it had been released by Nov 12, 2026.

Does it protect the heart or the kidneys?

Not shown yet. TRIUMPH-3 enrolled adults with severe obesity and heart disease, but it was built to measure weight, not heart events. Lilly said major heart events occurred less frequently than anticipated [Lilly, Jul 23, 2026]. There were 27 heart-related deaths, heart attacks or strokes on retatrutide and 23 on placebo. The hazard ratio was 1.12, with a range from 0.64 to 1.96, which is too uncertain to read either way [Lilly, Jul 23, 2026].

For contrast, semaglutide has proof of this kind. In the SELECT trial, major heart events occurred in 6.5% of people on semaglutide and 8.0% on placebo, a 20% lower risk. Those people had heart disease and overweight or obesity, without diabetes [NEJM, 2023 (SELECT)]. Retatrutide's own outcomes trial, with about 10,000 people, is running [ClinicalTrials.gov, NCT06383390].

The kidney data are early too. In TRANSCEND-CKD, 146 adults with chronic kidney disease took retatrutide or placebo for 24 weeks [ClinicalTrials.gov, NCT05936151]. Albumin in the urine, a sign of kidney damage, fell 53.65%, compared with 8.75% on placebo. But measured kidney filtration dipped slightly more on retatrutide: by 1.62 mL/min/1.73 m², against 0.19 on placebo [ClinicalTrials.gov, NCT05936151]. These are registry results, not yet peer reviewed.

Retatrutide benefits for women and for men

The trials enrolled plenty of both. TRIUMPH-2 was 48% female [Lancet, Sep 29, 2026], TRANSCEND-T2D-1 was 55% female [Lancet, Jun 6, 2026] and the phase 2 obesity trial was 51.8% male [NEJM, 2023]. The TRIUMPH trials also used sex as a balancing factor when assigning people to groups [Diabetes Obes Metab, 2025].

But no source we checked reports any result for women and men separately. So any claim that retatrutide works "better for women" or "better for men" isn't backed by published data. We found no retatrutide result on fertility, polycystic ovary syndrome or menopause either.

What hasn't retatrutide been shown to do?

Plenty of claims online go beyond the evidence. As of Nov 12, 2026, no trial has shown that retatrutide:

• prevents heart attacks, strokes or deaths;
• reverses liver scarring or prevents liver failure;
• prevents kidney failure or dialysis;
• builds or protects muscle strength;
• slows aging, improves mood or treats addiction.

None of these benefits applies to products sold online as retatrutide. Lilly says no one can legally sell it for human use, and that such products may hold the wrong ingredient entirely [Lilly, Oct 2026]. The retatrutide for sale guide explains what those listings are. The pillar page, what is retatrutide, has the full picture of where the drug stands.