Retatrutide for Knee Osteoarthritis: What Two Phase 3 Trials Show

Retatrutide eased knee osteoarthritis pain in two Phase 3 trials of 1,019 adults with a BMI of at least 27 and no diabetes. In TRIUMPH-1's main analysis at 80 weeks, the 12 mg group improved 1.8 points more than placebo on a 0-to-10 pain scale. It is not FDA-approved or available by regular prescription.

Those are averages for adults with a BMI of 27 or more, a doctor's knee osteoarthritis diagnosis, moderate-to-severe knee pain, and no diabetes, measured after 68 to 80 weeks. They don't show cartilage repair or fewer knee replacements. If your knee pain has another cause, or your BMI is lower, these trials don't describe you.

Below: the key knee numbers from both trials in one table, why the bigger dose did not show a clear knee-pain advantage, and what you can discuss with a clinician now.

Coming up: TRIUMPH-4 results are scheduled for presentation at the American College of Rheumatology's annual meeting on November 8, 2026 (official ACR program). We'll update this page when they're out.

RX Index Decision Verdict: Real knee-pain relief in trials — but no date to plan routine treatment around.

• Best for: people following the science, and people deciding whether to wait for retatrutide or start an approved option now.
• Not ideal for: anyone hoping to buy it now, pick a dose, or find out whether a worn knee will rebuild.
• The factor that matters most: the gap over placebo — 1.6 to 1.8 points out of 10 for the two main TRIUMPH-1 dose comparisons — and when routine access might start, which hasn't been set.

Retatrutide knee osteoarthritis results: key numbers in one table

Retatrutide was tested for knee osteoarthritis in two Phase 3 trials: TRIUMPH-4 (445 people, 68 weeks) and a knee group inside the larger TRIUMPH-1 trial (574 people, 80 weeks). In both, every dose reduced knee pain more than placebo. The exact numbers depend on the dose and on how each analysis handled stopping treatment, extra pain treatment, and other trial events.

First, two quick definitions.

Retatrutide is an experimental once-weekly shot from Eli Lilly. It acts on three hormone receptors: GIP, GLP-1, and glucagon. That's why people call it a "triple agonist."

WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) is the standard knee-arthritis questionnaire. The pain part asks about pain during everyday things like walking and stairs. In these trials it was scored 0 to 10. Zero is no pain. Ten is the worst. People started at about 6.

The Retatrutide Knee Ledger

Change in WOMAC pain score (0–10). A minus sign means less pain. "Gap" is the drug group minus the placebo group. TRIUMPH-1 gaps are the authors' reported estimates; TRIUMPH-4 gaps are our subtraction of Lilly's rounded averages.

Why one trial has several rows: picture a class where some students drop out halfway. One way to grade counts everyone who started. Another estimates how the class would have done if nobody quit. The journal's main "hybrid" analysis adds a different rule: after certain events, such as a prohibited knee procedure or too much extra pain medicine, it estimates no improvement from the starting score. That is a statistical rule, not a claim that each person's pain returned to where it started. TRIUMPH-4's knee "treatment-regimen" analysis also uses special rules for treatment failures. Each answers a slightly different question. None is a forecast for you. (How to read GLP-1 trials)

The reported gaps can differ slightly from subtracting the rounded scores. For example, the journal reports 1.8 points for TRIUMPH-1's main 12 mg comparison; we keep that reported estimate.

What's peer-reviewed and what isn't: the TRIUMPH-1 knee results are in a peer-reviewed journal, the New England Journal of Medicine. The TRIUMPH-4 figures above come from Lilly's results release. A conference abstract is listed for ACR 2026, but we could not read its full page during this check. As of October 24, 2026, we found no TRIUMPH-4 journal paper.

Weight, function, and quitting in TRIUMPH-4

Source: Lilly, Dec 11, 2025. Average starting weight 248.5 lb; average BMI 40.4. Efficacy analysis (assuming continued treatment and no specified treatment-failure events) unless noted. Percent and pound changes are Lilly's separately reported estimates, not conversions from the pooled starting weight.

We could verify the TRIUMPH-1 knee pain results in the full journal paper, but not a separate weight-loss breakdown for that knee group. The paper's overall weight figures describe the whole trial, so we do not substitute them for knee-group results. For weight results across all retatrutide trials, see retatrutide weight loss results. Every study, tracked: retatrutide clinical trials.

Not waiting? Start with what fits you now

Retatrutide isn't available by regular prescription yet. But if you meet the prescribing rules, an approved GLP-1 medicine could be part of your weight-care plan. The right one isn't the same for everyone. It depends on your state, your insurance and its drug list, your medical needs, a shot or a pill, and your budget. The RX Index's Find My GLP-1 Path tool asks a few quick questions and shows a suggested treatment path and provider pricing to review. It does not check your plan's coverage or copay.

See which GLP-1 path fits you

What does "75% less knee pain" really mean?

The famous "75%" is how much the average pain score dropped in one TRIUMPH-4 group. It doesn't mean 75 out of 100 people became pain-free. And it isn't 75% better than placebo — the placebo group's score dropped about 40% too.

Here's the math, as a made-up example. Say a group's average pain score starts at 6 and ends at 1.5. That's a 4.5-point drop, which is 75% of 6. Some people in that group might still hurt a fair amount. Others might feel almost nothing. The 75% describes the average, not each person.

Three things the headline skips:

• It's the 9 mg number. Lilly reported −75.8% for 9 mg and −74.3% for 12 mg. Putting 75.8% next to 12 mg would be wrong.
• The percent wasn't planned in advance. Lilly calls those percentages a post-hoc analysis — one not set out in the original analysis plan (Lilly release).
• Placebo groups improved about half as much. In the efficacy analyses, average pain fell 2.4 points on placebo versus 4.5 in TRIUMPH-4's 9 mg group, and 2.2 versus 4.3 in TRIUMPH-1's 12 mg group. Those ratios are about 53% and 51%, using the rounded figures above. They compare group averages; they do not tell us what caused each person's relief.

Why does the placebo group matter? Both groups in these trials also got guidance on diet and physical activity. Comparing them shows the added benefit of retatrutide in that setting. The studies do not tell us how much of the placebo group's improvement came from study care, expectations, or changes in pain over time.

We're not knocking the drug. A gap of about 2 points on a 10-point scale is real. We just want you to know the added benefit over the comparison group. More on that idea: placebo-adjusted results, explained.

How many people were pain-free?

In TRIUMPH-4, 14.1% of the 9 mg group and 12.0% of the 12 mg group reported no knee pain at week 68, versus 4.2% on placebo. That's roughly 1 in 7 to 8 on retatrutide and 1 in 24 on placebo. Lilly calls this a post-hoc finding based on observed data for the efficacy analysis, and its release doesn't give the full denominator or say exactly how "pain-free" was defined. Treat it as a hopeful signal, not a prediction.

Did the higher dose help knees more?

The reported averages were close. In TRIUMPH-4, the 9 mg and 12 mg groups had almost the same average pain reduction, even though 12 mg took off more weight. More people on 12 mg quit because of side effects.

Sources: NEJM supplement, Table S6, Lilly, Dec 11, 2025. Pain and weight figures use each study's efficacy analysis. Arrows compare separate study groups, not a dose-change plan.

Our read: the higher dose did not show a clear knee-pain advantage in these averages, and TRIUMPH-4 reported more dysesthesia and more treatment stops due to adverse events at 12 mg. These comparisons do not prove that the doses work equally well, and no retatrutide dose is approved. So this is a fact about the studies, not a dosing tip. If retatrutide is ever approved, the dose is your prescriber's call.

Who were the knee trials for — and do they look like you?

Both trials enrolled adults with a BMI of 27 or higher, a knee osteoarthritis diagnosis, and moderate-to-severe knee pain. Both excluded people with diabetes and required grade 2–3 changes on a knee X-ray. They did not include grade 4, the most advanced grade.

Sources: NEJM supplement, Table S4 and trial methods, published TRIUMPH trial design, TRIUMPH-4 registry record, Lilly, Dec 11, 2025.

BMI (body mass index) is a number from your height and weight. Don't know yours? Our GLP-1 BMI chart shows where you land. X-ray grade 2–3 means there are definite signs of arthritis on the Kellgren-Lawrence scale, the 0-to-4 scale doctors use to grade arthritis on an X-ray. Grade 4, the most advanced grade, was outside these trials.

A quick self-check:

1. Has a doctor told you it's knee osteoarthritis, usually with an X-ray?
2. Is your BMI 27 or higher?
3. Is your knee pain between 4 and 9 out of 10?

Three yeses match some entry rules. The trials used the WOMAC questionnaire; a general pain rating is only a rough screen. Diabetes status, X-ray findings, and other rules still matter. It doesn't mean you'd get the same result.

Start with your own clinician, not a website, if you're under 18, pregnant or planning to be, have type 1 diabetes, have a history of an eating disorder, have a personal or family history of medullary thyroid cancer, or have MEN 2 (the thyroid-cancer history and MEN 2 are listed reasons not to use approved GLP-1s like Wegovy and Zepbound). More: GLP-1 hard contraindications.

Does retatrutide repair the knee, or is it just weight loss?

The trials measured knee pain, daily function, and weight. They did not show cartilage regrowth, less damage on X-rays, or fewer knee replacements. They also can't tell how much of the relief came from weight loss and how much, if any, came from a direct effect on the joint.

Think of a worn knee like a worn road. Less traffic makes the ride smoother. It doesn't fill the potholes.

What about inflammation? In TRIUMPH-4, Lilly reported a drop in hsCRP, a blood test for body-wide inflammation, but didn't give the size in its release (Lilly). A lower blood marker doesn't prove the knee joint itself is less inflamed. More on this: GLP-1s and inflammation.

What side effects showed up in the knee trial?

The most common side effects in TRIUMPH-4 were stomach and gut problems — nausea, diarrhea, constipation, and vomiting — plus lower appetite. A skin-feeling side effect called dysesthesia was much more common at 12 mg. About 1 in 8 people on 9 mg and nearly 1 in 5 on 12 mg stopped treatment because of side effects.

TRIUMPH-4, 68 weeks. Source: Lilly, Dec 11, 2025.

Lilly said the dysesthesia was generally mild and rarely made people stop. It also said quitting was closely tied to starting BMI and included people who stopped because they felt they were losing too much weight. Among retatrutide users who started at BMI 35 or higher, fewer quit.

In the full TRIUMPH-1 trial (everyone, not just the knee group), the published paper reports that 4.1%, 6.5%, and 11.1% stopped treatment for adverse events on 4, 9, and 12 mg, versus 4.6% on placebo. That measure excludes deaths (NEJM main text and participant flowchart). Serious adverse events occurred in 7.7%, 7.7%, and 10.5%, respectively, versus 5.5% on placebo. These were events during the trial, not all proven to be caused by the drug.

Two things worth raising with a clinician if you have bad knees: strong thigh muscles support a knee, and big weight loss can take some muscle with it (NIAMS knee-care guidance; GLP-1 nutrition advisory; retatrutide and muscle loss). And if you're an older woman, ask about bone health (GLP-1s and bone density). Full details: retatrutide side effects and retatrutide skin sensitivity.

Severe stomach pain that won't go away, or vomiting you can't stop, needs a clinician right away (Wegovy safety information).

Can retatrutide cause joint pain?

Joint pain has been reported during retatrutide treatment. In TRIUMPH-2, a separate 80-week trial in adults with overweight or obesity and type 2 diabetes, joint pain ("arthralgia") was reported in about 4%, 6%, and 6% on 4, 9, and 12 mg, versus 5% on placebo (The Lancet, Table 301861-1)).

Those reports do not prove retatrutide caused the pain, and they are not knee-osteoarthritis subgroup rates. In both knee trials covered above, average knee pain went down. That does not rule out new joint pain in an individual.

If your joints hurt after using a vial sold online as "reta," its contents and quality cannot be assumed from the label. It is not authorized Lilly trial or expanded-access supply. Any new leg pain with swelling, warmth, or redness should be checked promptly (CDC guidance).

Is retatrutide approved for knee osteoarthritis — and when could you get it?

No. Retatrutide isn't FDA-approved for any use. Lilly says it plans to ask the FDA for approval in the first quarter of 2027 — January through March — and that its trial data support filings for knee osteoarthritis pain, obesity, and obstructive sleep apnea. No approval date has been set.

That's from Lilly's July 23, 2026 release, which also says retatrutide "cannot be legally sold or marketed for human use." Lilly repeated the planned Q1 2027 submission in its September 29 update.

Our math is only a scenario: a January–March 2027 submission plus an 8- or 12-month review target points to a possible FDA action between September 2027 and March 2028, if the FDA accepts the application for filing and those targets apply without an extension. That is not an announced approval or launch date. The FDA has not announced retatrutide's review type or decision date, and approval for knee pain specifically isn't guaranteed. An October 2 FDA letter and Lilly's October 8 court filing document a dispute over which type of application it should use. We track that on our retatrutide news page.

Why a knee label would matter: Wegovy and Zepbound are approved for weight management and other specified uses, not knee OA. A knee-specific retatrutide approval would give clinicians a distinct approved use to discuss; it would not automatically make an insurer cover it.

Can you get retatrutide now?

Not with a regular prescription. Both knee trials are finished, and Lilly lists a narrow expanded-access program that only a doctor can request, for patients with serious obesity-related complications. The FDA says retatrutide can't be used in compounding under federal law.

Expanded access rules (all five must be true):

1. You're 18 or older.
2. Your BMI is 35 or higher even after sticking with, and tolerating, the highest available dose of a long-term weight-loss medicine.
3. You have two or more serious or life-threatening obesity-related conditions and are receiving standard care for them.
4. You can't join an ongoing retatrutide or similar investigational-drug trial because of its entry rules or because no enrolling site is reasonably accessible.
5. Your doctor has gone over all standard options with you, including weight-loss surgery.

A medical reason you shouldn't take retatrutide rules you out. Knee osteoarthritis alone doesn't qualify you. Meeting the list does not guarantee access; Lilly assesses requests individually. Lilly's public FAQ says retatrutide is available only in trials (Lilly FAQ), but the separate expanded-access listing above is real and current. The full walkthrough is on our retatrutide early access page.

What about "research" retatrutide sold online?

The FDA says retatrutide isn't part of any approved drug, can't be compounded, and has warned companies selling it labeled "for research purposes" or "not for human consumption" (FDA). A consumer vial sold online is not authorized Lilly trial or expanded-access supply. Its identity, strength, purity, and sterility cannot be assumed. More: compounded retatrutide and how to avoid fake GLP-1 medications.

If you used something sold as retatrutide and you're worried about a reaction, call Poison Control at 1-800-222-1222. Call 911 for trouble breathing, collapse, or a seizure.

What can you do for your knee while you wait?

You don't have to wait. If you meet the prescribing rules, a clinician can consider an FDA-approved GLP-1 today. The American College of Rheumatology now conditionally recommends GLP-1 medicines for people with knee osteoarthritis and obesity to help reach a healthy weight with diet and exercise. Exercise and weight loss remain its strongly recommended basics.

What the 2026 arthritis guideline says

In September 2026, the American College of Rheumatology approved its updated osteoarthritis guideline summary (ACR 2026 summary):

• GLP-1 medicines: conditionally recommended for knee osteoarthritis with obesity, to help reach a healthy weight along with diet and exercise. "Conditional" means it depends on the person — their benefits, risks, wishes, and access.
• Weight loss: strongly recommended for knee and hip osteoarthritis with overweight or obesity.
• Exercise: strongly recommended.
• Physical therapy: clinicians should refer you if pain, flares, or fatigue get in the way of exercise or daily life.

This is a clinical recommendation about GLP-1 medicines, not an FDA approval of retatrutide.

Is retatrutide better than Wegovy for knee pain?

No trial has compared them head-to-head. Once-weekly injected semaglutide 2.4 mg — a Wegovy injection dose — has its own positive knee trial, STEP 9: 407 adults with obesity over 68 weeks, with knee pain scored 0 to 100 (STEP 9 abstract).

Here's a rough look on the same 0-to-10 ruler. We divided STEP 9's scores by 10. Changing the scale does not make these a head-to-head comparison: STEP 9's numbers include treatment stops, while the retatrutide numbers below estimate continued treatment without specified trial events.

Sources: STEP 9 full paper and supplement, TRIUMPH-1 supplement, Table S6, and TRIUMPH-4 release. STEP 9's reported adjusted gap was 14.1 on its 0–100 scale, or 1.41 on a 0–10 scale.

Different trials, different people, different lengths, and different analysis rules. This table cannot tell us which drug gives more knee relief, or whether more weight loss produces more relief. The biggest difference today is simpler: Wegovy is available through routine prescribing; retatrutide remains investigational. STEP 9 tested the 2.4 mg injection, not Wegovy tablets or compounded semaglutide.

Tirzepatide's dedicated STOP KNEE-OA trial is ongoing, with no results posted as of October 24, 2026. Its registered primary outcome is the percentage of participants who have the target knee replaced within 72 weeks, with primary completion estimated for May 2027. For how every GLP-1 stacks up for knees, see GLP-1 medicines and knee osteoarthritis. Comparisons: retatrutide vs semaglutide and retatrutide vs tirzepatide.

How people actually get an approved GLP-1

Commercial insurance. Check your own plan's drug list and prior-authorization rules. For example, Cigna's Wegovy injection policy, effective September 1, 2026, includes a starting BMI of 30 or higher, or 27 or higher with a listed condition, including knee osteoarthritis. Its other treatment rules must also be met, and your plan can exclude weight-loss drugs. Prior authorization is a permission slip from your insurer before it pays. Our GLP-1 knee osteoarthritis page explains the example; see also how to get insurance to cover a GLP-1.

Medicare. The Medicare GLP-1 Bridge can cover certain approved weight medicines for eligible Part D members age 18 or older. A BMI of 35 or higher when GLP-1 treatment started meets its weight criterion without another listed condition. Plan eligibility, treatment rules, and clinician prior authorization still apply. The other qualifying BMI bands start at 27 and require specific conditions; knee osteoarthritis isn't one of them. If the medicine is prescribed for a Part D-covered use, such as type 2 diabetes, it goes through the plan instead of the Bridge. Retatrutide is not a Bridge drug (CMS rules). Details: Medicare GLP-1 Bridge.

Medicaid. Your state decides. See what GLP-1 Medicaid covers.

Paying cash. Brand-name medicines are sold through manufacturer programs and telehealth providers. Ro, for example, doesn't offer retatrutide, but its weight-loss program offers FDA-approved medicines after clinician review. Its free coverage check covers Ozempic, Wegovy, and Zepbound pens; it is not a prescription or a treatment request (Ro review). Compounded GLP-1s aren't FDA-approved, and the FDA doesn't review them for safety, effectiveness, or quality before they're sold. The FDA says they should be used only when an approved drug cannot meet a patient's medical needs. These trials did not test compounded products or establish equivalent knee-pain benefits.

Say you're 58, your BMI is 36, you're on an employer plan, and your surgeon wants you lighter before a knee replacement. Retatrutide has no routine-prescription start date. Finding out whether your plan covers an approved GLP-1 and what its authorization rules require is something you can do this week.

Waiting is a choice, not a treatment plan. If you'd rather explore treatment now, see which paths fit your insurance, budget, and situation.

Compare current GLP-1 paths

Five questions to take to your appointment

1. Is my knee pain definitely osteoarthritis, and how bad is it on an X-ray?
2. What can help my pain and daily function right now?
3. Do I meet the rules for an approved GLP-1, and what are the risks for me?
4. Which exact medicine has evidence for what we're treating — my weight, my knee, or both?
5. How do we protect my thigh muscles and bones while I lose weight?

How we checked this page

We checked the trial numbers against full journal papers and supplements, Lilly's TRIUMPH-4 release, official study records, FDA sources, and the new arthritis guideline summary on October 24, 2026. We also read the coverage policies and provider pages linked below. Conference dates came from ACR's official program; its full abstract pages were not accessible.

The RX Index is the independent GLP-1 decision resource that scores telehealth providers and treatment paths on clinical legitimacy, care quality, transparency, access, and cost, so readers can choose the path that fits their situation.

What we actually verified

What we couldn't confirm: details available only in the inaccessible ACR abstracts; quitting rates or per-dose weight loss for the TRIUMPH-1 knee group alone; the full denominator and exact definition for Lilly's "pain-free" result; expanded-access costs; any approval or launch date. What we didn't do: take retatrutide, contact study sites, or request expanded access. No physician reviewed this version of the page.

See how we evaluate evidence and treatment paths.

Retatrutide and knee osteoarthritis FAQ

Does retatrutide help with arthritis?

In TRIUMPH-1 and TRIUMPH-4, retatrutide lowered knee pain more than placebo in adults with knee osteoarthritis, a BMI of at least 27, and no diabetes. In TRIUMPH-1's main analysis, the 9 and 12 mg groups improved 1.6 and 1.8 points more than placebo on a 0-to-10 scale. These results do not establish a benefit for other kinds of arthritis. It isn't approved for any use yet.

Does retatrutide help with inflammation?

Lilly reported lower hsCRP, a blood marker of inflammation, in TRIUMPH-4. That's a lab number, not proof that a joint is less inflamed. The results reviewed here do not establish repair of the joint on imaging.

Can you take a GLP-1 if you have osteoarthritis?

Yes. Osteoarthritis isn't a reason you can't take an approved GLP-1, and the American College of Rheumatology now conditionally recommends GLP-1 medicines for knee osteoarthritis with obesity to help reach a healthy weight with diet and exercise. A prescriber still checks your full health history and whether you meet the weight rules.

Can peptide injections help knee arthritis?

Retatrutide is a peptide, but in the trials it was a weekly shot under the skin, not into the knee. Products sold online as "research peptides" aren't approved medicines, and the FDA warns against buying them. Ask your doctor about approved knee treatments.

Can retatrutide cause joint pain?

Joint pain was reported in about 4–6% of retatrutide users and 5% of placebo users in TRIUMPH-2, a separate trial in adults with type 2 diabetes and overweight or obesity (The Lancet, Table 301861-1)). Those reports do not prove the drug caused the pain. They are not rates for the knee-OA groups discussed above.

Does retatrutide work for rheumatoid arthritis?

These knee osteoarthritis trials do not show whether retatrutide helps rheumatoid arthritis. RA is an immune disease that needs its own treatment. Start with a rheumatologist.

Does "75% less pain" mean most people became pain-free?

No. It's the average drop in the pain score for the 9 mg group in TRIUMPH-4. In the exploratory, observed-data analysis, about 1 in 7 to 8 on retatrutide reported no knee pain, versus about 1 in 24 on placebo. It was not a count of every randomized participant.

Is 12 mg better than 9 mg for knee pain?

TRIUMPH-4 showed similar average pain reductions at 9 and 12 mg, and more people on 12 mg quit because of side effects. That does not prove the doses work equally well. No dose is approved, so this is a trial finding, not advice.

Is retatrutide better than Wegovy for knee pain?

No head-to-head trial establishes that. STEP 9 tested injected semaglutide 2.4 mg; its results and the retatrutide results use different populations and analysis rules. Rescaling the pain scores does not show a winner. Wegovy is available through routine prescribing; retatrutide remains investigational.

Does retatrutide rebuild knee cartilage?

That wasn't shown. The published results report pain and function improvements; they do not establish cartilage regrowth.

Could retatrutide help me avoid a knee replacement?

Unknown. These results do not establish fewer knee replacements; knee procedures were tracked as events that could affect the pain analysis. If surgery has been recommended, talk with your surgeon before changing any plans.

How fast would my knee pain improve?

The main results were measured at 68 and 80 weeks. The results reviewed here do not establish when an individual would first feel relief or how long knee relief lasts after stopping.

When will retatrutide be available for knee pain?

No date is set. Lilly plans to submit in January–March 2027. FDA review targets are not approval promises, and no retatrutide decision date has been announced. Approval for knee pain specifically isn't guaranteed.

Can I join a retatrutide knee trial?

Both knee trials are finished. On October 24, 2026, the registry listed one recruiting Lilly-sponsored study with a retatrutide arm, the liver-disease study SYNERGY-Outcomes. Check Lilly's trial finder and confirm that a suitable site and the retatrutide arm are enrolling.

Will insurance cover retatrutide for knee arthritis?

There is no FDA-approved retail retatrutide product with routine pharmacy coverage to check. Trial and expanded-access arrangements are separate, and we have not verified their costs or insurance terms. Some plans already count knee osteoarthritis among the qualifying conditions for approved weight medicines, which is worth checking today.

Is "reta" sold online the same drug?

You cannot assume that it is. A consumer vial sold as "reta" is not authorized Lilly trial or expanded-access supply, and its contents and quality are unverified. The FDA says retatrutide cannot be compounded and warns against products sold to consumers as "research use only."

Still not sure which GLP-1 path fits you? Take The RX Index's free Find My GLP-1 Path quiz — about 2 minutes, no signup.

Sources

• Eli Lilly. TRIUMPH-4 topline results. Dec 11, 2025. Checked Oct 24, 2026.
• Jastreboff AM, et al. Retatrutide, a triple hormone receptor agonist, for treatment of obesity. New England Journal of Medicine, Sept 29, 2026. Full paper and supplement checked Oct 24, 2026.
• Bellido V, et al. Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2)01861-1). The Lancet, Sept 29, 2026. Full paper and supplement checked Oct 24, 2026; joint-pain rates from Table 3.
• Bliddal H, et al. Once-weekly semaglutide in persons with obesity and knee osteoarthritis (STEP 9). New England Journal of Medicine, 2024. Full paper and supplement checked Oct 24, 2026.
• TRIUMPH-1 and TRIUMPH-2 trial design. Diabetes, Obesity and Metabolism, published online Oct 15, 2025. Checked Oct 24, 2026.
• American College of Rheumatology. ACR Convergence 2026 osteoarthritis program. TRIUMPH-4 talk scheduled Nov 8 and TRIUMPH-1 knee poster Nov 10, 2026. Schedule checked Oct 24, 2026. Related abstract 0871 and abstract 2573 pages were inaccessible; their full contents were not verified.
• ClinicalTrials.gov. TRIUMPH-4, NCT05931367, updated Jan 21, 2026; TRIUMPH-1, NCT05929066, updated Aug 21, 2026. Records checked Oct 24, 2026.
• ClinicalTrials.gov. Retatrutide expanded access, NCT07629401. Record updated Aug 6, 2026. Checked Oct 24, 2026.
• ClinicalTrials.gov. SYNERGY-Outcomes, NCT07165028, updated Oct 8, 2026; STOP KNEE-OA, NCT06191848, updated Oct 13, 2026. Records checked Oct 24, 2026.
• U.S. Food and Drug Administration. FDA's concerns with unapproved GLP-1 drugs used for weight loss. Content current Oct 1, 2026. Checked Oct 24, 2026.
• Novo Nordisk. Wegovy prescribing information, revised June 2026. Eli Lilly. Zepbound prescribing information, revised August 2026. Checked Oct 24, 2026.
• Eli Lilly. TRIUMPH-1 and TRANSCEND-T2D-1 results (ADA 2026). June 6, 2026. Historical release checked Oct 24, 2026; the later NEJM paper supplies the TRIUMPH-1 safety rates used here.
• Eli Lilly. TRIUMPH-2 and TRIUMPH-3 results; planned Q1 2027 filing, July 23, 2026; updated Phase 3 results and filing plan, Sept 29, 2026. Checked Oct 24, 2026.
• U.S. Food and Drug Administration. PDUFA VII performance goals, fiscal years 2023–2027, review-goal section. Checked Oct 24, 2026.
• FDA letter dated Oct 2, 2026, filed Oct 8; Lilly court brief dated Oct 8, 2026. Checked Oct 24, 2026 for the positions stated in those documents.
• Eli Lilly. Q3 2026 earnings call, scheduled Oct 29, 2026. Event listing checked Oct 24, 2026.
• Eli Lilly. What to know about retatrutide (FAQ) and expanded-access policy. Checked Oct 24, 2026.
• American College of Rheumatology. 2026 osteoarthritis guideline summary. Approved Sept 8, 2026; posted Sept 14, 2026. Checked Oct 24, 2026.
• Centers for Medicare & Medicaid Services. Medicare GLP-1 Bridge information for providers. Checked Oct 24, 2026.
• Cigna. Wegovy injection coverage policy IP0814. Effective Sept 1, 2026. Checked Oct 24, 2026; each member's benefit document controls coverage.
• Ro. Weight-loss program and GLP-1 insurance coverage checker. Checked Oct 24, 2026.
• National Institute of Arthritis and Musculoskeletal and Skin Diseases. Osteoarthritis care and rheumatoid arthritis. Checked Oct 24, 2026.
• Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory. Obesity, May 30, 2025. Checked Oct 24, 2026 for muscle and bone considerations.
• CDC. About venous thromboembolism, March 5, 2025. NHS. Deep vein thrombosis, reviewed April 30, 2026. Poison Control. First aid for poisonings. Checked Oct 24, 2026.
• The RX Index. How Find My GLP-1 Path works and methodology. Checked Oct 24, 2026.