Estimated reading time: 13 minutes
On May 21, 2026, Eli Lilly and Company (makers of tirzepatide and orforglipron) reported that retatrutide had delivered the largest weight loss ever recorded in a Phase 3 obesity trial, averaging 28.3% at 80 weeks and reaching 30.3% at 104 weeks in patients with a BMI of 35 or higher. Those are promising early results from a once-weekly injection, and word has traveled fast. Many patients are already beginning to ask for retatrutide by name, even though FDA approval is likely a year or more out and no physician can prescribe it yet.
Sermo polled over 400 physicians, asking how they would use triple agonists like retatrutide once the drugs become available. The answers reflect a profession that trusts the science but wants to watch how it performs before leaning in. Patient interest and demand is already well documented. Sermo’s Barometer 45 survey—a real-time survey series that captures the observations, treatment patterns, and insights of global physicians—found that 48% of respondents had patients disclose using non-FDA-approved peptides in the past year, and 34% said patients ask about peptide therapies at least occasionally. Triple agonists like retatrutide are the next wave of that demand.
One clarification about the name is that “triple agonist” is accurate, but the popular “GLP-3” label is a misnomer. Retatrutide acts on three separate receptors, GLP-1, GIP, and glucagon, not a third GLP receptor, which does not exist. GLP-1 curbs appetite and slows gastric emptying, GIP supports insulin regulation and adds to the appetite effect, and glucagon raises energy expenditure and fat oxidation. That third mechanism is what sets retatrutide apart from the GLP-1 and dual agonist drugs already in use.
A Sermo member and general practitioner captured the bind many are in, “I see growing patient demand for triple agonists like retatrutide despite lacking FDA approval or formal guidelines, which puts me in a difficult position managing expectations while ensuring safety and equitable access once these therapies become available.”
Physicians on Sermo are already comparing notes on where triple agonists fit and how to handle the patient conversations. Join the community to see what your peers are saying.
What the TRIUMPH results actually show
The TRIUMPH program is large and still reporting. Limited peer‑reviewed articles have been published, but two trials have been reported by Eli Lilly so far: TRIUMPH-1 and TRIUMPH-4. Here’s the clinical read:
TRIUMPH-1 (the pivotal obesity trial)
TRIUMPH-1 randomized 2,339 participants 1:1:1:1 to retatrutide at 4mg, 9mg, 12mg, or placebo. The headline numbers came from the 12mg dose.
- Top-dose weight loss: 28.3% on average at 80 weeks, around 70 lbs on a 248.5 lb starting weight.
- Responder rates: 62.5% of participants lost at least 25% of their body weight, 45.3% lost at least 30%, and 27.2% lost at least 35%
- Lowest dose: the 4mg escalation arm still reached 19.0%, with a discontinuation rate below placebo.
- Longer follow-up: the 104-week extension pushed loss to 30.3% in patients with a BMI of 35 or higher, an average of about 85 lbs lost.
All three doses met the primary endpoints and key secondary endpoints, so the benefit isn’t limited to the highest, hardest-to-tolerate dose.
TRIUMPH-4 (obesity plus knee osteoarthritis)
TRIUMPH-4 tested the drug in patients who had both obesity and knee osteoarthritis, pairing weight outcomes with joint outcomes. The highest dose produced 28.7% weight loss alongside a 75.8% improvement in knee OA pain, a 14 mmHg drop in systolic blood pressure, and better cardiovascular risk markers, including non-HDL cholesterol. Those combined results make the case for treating obesity as a driver of several conditions at once, not just a number on the scale to bring down.
Safety and tolerability
The adverse event profile looked like what you might expect from an incretin-based therapy, including GI effects like nausea, diarrhea, and vomiting. Discontinuation tracked with dose in TRIUMPH-1 findings, running 4.1% at 4mg, 6.9% at 9mg, and 11.3% at 12mg, against 4.9% for placebo.
Two findings are worth watching. Researchers reported a new dysesthesia signal, and some physicians flag a possible cardiovascular signal at the higher dose that could narrow the usable dose range. Both need further evaluation in the TRIUMPH-Outcomes trial rather than counting as confirmed risks, but they’re worth tracking over time.
A Sermo member and endocrinologist made the practical point: “Higher dose of reta has potential CV signal, so likely dose range may end up being very similar to dual agonists.”
How retatrutide compares to current options
Semaglutide (Wegovy) — GLP-1 mono-agonist
- Receptor: GLP-1
- Mechanism: Appetite suppression and slowed gastric emptying
- Phase 3 mean weight loss: ~15% (NEJM)
Tirzepatide (Zepbound) — GLP-1/GIP dual agonist
- Receptors: GLP-1 and GIP
- Mechanism: Adds improved insulin regulation plus further appetite suppression
- Phase 3 mean weight loss: ~22% (NEJM)
Retatrutide — GLP-1/GIP/glucagon triple agonist
- Receptors: GLP-1, GIP, and glucagon
- Mechanism: Adds increased energy expenditure and fat oxidation
- Phase 3 mean weight loss: ~28% (Lilly press release)
Retatrutide is the third step in a clear progression. Each added receptor has brought meaningfully more weight loss, building up from semaglutide, the GLP-1 benchmark most physicians already know well. The glucagon component is doing something the other two cannot, adding energy expenditure and fat oxidation on top of appetite suppression. This three-receptor approach first proved itself in an earlier Phase 2 trial before TRIUMPH scaled it up. The tradeoff is that more mechanisms also mean a more complex safety and monitoring picture. Before positioning any of these agents, it helps to see how peers will rate them in Sermo’s physician drug ratings database.
How physicians on Sermo are thinking about adoption
The Sermo poll shows how physicians are working through a new class of drugs, from where it fits to who they would treat first.
Where triple agonists fit in the treatment hierarchy
Asked how triple agonists would fit into their decisions if the efficacy holds up, physicians split four ways:
- Those who want Phase 3 outcome data first (34%): They are not committing to anything until the long-term evidence is in.
- Those who will reserve them for failures (32%): Triple agonists become an option only after GLP-1 or dual agonist therapy falls short.
- Those who see first-line potential (22%): For the right patient, they would reach for a triple agonist early.
- Those who would limit use (12%): Only recommending triple agonists in specific high-risk populations.
Taken together, physicians are generally optimistic but not ready to move triple agonists ahead of current first-line options without more evidence. An internal medicine physician on Sermo captured this measured approach, “A drug like retatrutide has the potential to be a real breakthrough. However, when looking at the complexity of the medication, being one that acts on three particular hormone receptor agonists in the body at once, it should be as closely scrutinized as possible … I certainly do not yet feel comfortable that the drug should receive final FDA approval at this time.”
What benefit would most influence adoption?
When physicians were asked which benefit would move them most toward adoption, total weight loss came in surprisingly low:
- Better cardiometabolic outcomes (35%): Proof of reduced cardiovascular risk carried the most weight.
- Improved durability (27%): Weight loss that holds, with less regained over time.
- Higher total weight loss (16%): The headline number, but for most physicians, this is not the deciding factor.
- Broader applicability (11%): Fewer contraindications and use across more patient types.
- No single benefit (10%): Some physicians agreed that no one factor is enough on its own.
The takeaway is that physicians are not chasing the biggest number on the scale. They want evidence that triple agonists reduce the downstream events that harm patients.
The barriers physicians see
When the question turned to what stands in the way of routine use, the obstacles physicians named were less about the drug and more about the system around it.
- Insurance and cost (36%): The single biggest barrier, by a wide margin.
- Missing long-term data (24%): Not enough outcomes evidence yet.
- Managing side effects (15%): Tolerability and the GI profile.
- Unclear guidelines (12%): No settled framework yet for which patients get the drug and when.
- Patient education time (11%): The counseling and expectation-setting each patient will need.
Physicians appear ready to prescribe—once the evidence is solid. The holdups would likely be payer coverage, unclear treatment guidelines and long-term safety, not clinician willingness to prescribe. What patients actually pay comes down to the cost of weight loss drugs and to who controls coverage, from insurers to pharmacy benefit managers. A radiologist on Sermo summed up the reality, saying, “Coverage will always be the ultimate issue.”
Which patients to prioritize: What the data and the Sermo community suggest
If retatrutide reaches the market, the next question is who gets it first, and the Sermo physician community answer leans heavily toward health burden rather than BMI. In the poll, 43% of respondents would prioritize patients with obesity plus cardiometabolic comorbidities, 35% voted for patients who have failed GLP-1 therapy, while 13% pointed to severe obesity alone.
The comorbidity-first approach
The largest group would start with patients whose excess weight is driving diabetes, cardiovascular risk, sleep apnea, mobility limitations, or fatty liver disease. That instinct lines up with TRIUMPH-4, where weight loss results came bundled with reduced OA pain, blood pressure, and lipids. A dermatologist on Sermo described the logic, “Rather than focusing solely on BMI, I’d prioritize patients whose excess weight is driving the greatest health burden … The biggest impact may come from identifying patients where meaningful weight reduction could alter the trajectory of multiple chronic conditions at once.”
The step-therapy approach
A close second group, at 35% of respondents, would hold triple agonists in reserve for patients who haven’t responded well enough to GLP-1 or dual agonist therapy. That positions retatrutide as a rescue option rather than a first move, much like where many physicians started with tirzepatide.
Specialty-specific considerations
Where physicians land on triple agonists often comes down to their specialty.
An internal medicine resident on Sermo wanted renal data before anything else: “The only GLP-1 based agent with solid evidence in chronic kidney disease is semaglutide (FLOW trial), showing meaningful renoprotective effects. Triple agonists like retatrutide look impressive for weight loss in the general population, but we have no renal outcomes data yet. My patients with CKD will have to wait for that evidence before I jump on board.”
A psychiatry resident had a specific unmet need in mind. “Antipsychotic-related weight gain remains a major challenge in psychiatry. Triple agonists may become a valuable option for patients who do not respond sufficiently to current treatments.”
What physicians should be doing now
Approval is projected for late 2027 at the earliest, but the work of preparing for these drugs starts now, including how you talk to patients and manage expectations today.
Managing patient expectations before approval
Patients may already be asking for retatrutide by name, so a consistent message helps. Acknowledge the data, be clear that the drug is investigational and available only inside clinical trials, give the realistic late-2027 timeline, and redirect patients who need treatment now toward approved options like semaglutide and tirzepatide where applicable.
Some patients will seek out gray-market access through unregulated online sources or non-FDA-approved compounding, and some may reach for unregulated supplements marketed as triple agonist alternatives. An FDA advisory committee meets in July 2026 to weigh whether pharmacies can compound certain peptide-based therapies, but for now retatrutide has no legitimate channel outside of a trial. Sermo’s Barometer 45 report found that patient demand for peptides has already outpaced both clinical consensus and regulation, so this is a conversation to get ahead of now. Advise your patients of the risks associated with unregulated access and try to direct them toward safer options.
Building the clinical infrastructure
Three receptor systems firing at once make for a more complicated metabolic picture than a GLP-1 mono agonist, so practices getting ready for these drugs should plan for a few things:
- Broader monitoring: Plan for labs and checks that routine GLP-1 follow-up does not cover.
- Tolerability that worsens by dose: Higher doses mean more dropouts, so dosing and counseling matter more.
- CV monitoring at higher doses: Blood pressure and heart rate stay on the list until TRIUMPH-Outcomes reports.
- Grounding expectations against the hype: Patients arrive with viral before-and-afters in mind, so realistic counseling and good communication is part of every visit.
A general practitioner and orthopedic surgeon on Sermo framed the mindset, “The strategy we must adopt right now is one of rigorous preparation and patient education. While we wait for the FDA, our focus has to be on building the clinical infrastructure required to manage these potent multi-hormone pathways safely. Triple agonists don’t just mimic GLP-1. They simultaneously target GIP and glucagon receptors, meaning we will need to be hyper-vigilant about a completely new metabolic profile, including heart rate variations and heightened gastrointestinal or energetic shifts.”
A physiatry and family medicine resident on Sermo flagged a risk that comes with rapid weight loss, “My biggest clinical concern with such rapid and massive weight reduction is how we will effectively monitor and preserve lean muscle mass to prevent medically induced sarcopenia, especially as these indications expand to older populations.” That worry about preserving lean muscle is already familiar to many physicians from the current GLP-1 class.
Watching the remaining TRIUMPH readouts
TRIUMPH-1 and TRIUMPH-4 are just the first two to report, and several more readouts are expected through 2026. Together they will shape how broadly retatrutide can be used.
- TRIUMPH-2: In type 2 diabetes.
- TRIUMPH-3: In established cardiovascular disease.
- TRIUMPH-5: Head‑to‑head trial of retatrutide vs tirzepatide in adults with obesity.
- TRIUMPH-Outcomes: On long-term cardiovascular outcomes.
These results will help determine whether the drug earns a broad or narrow indication, and whether the cardiovascular data supports wider use or ends up limiting it. These are the outcomes the 34% of Sermo respondents who want more data are waiting on.
The prescribing timeline physicians can expect
Sermo also asked how soon physicians would prescribe if the drug were approved today, and results show that most would wait:
- 39% would wait up to six months to review post-approval data and guidelines.
- 19% would wait 1 to 2 years for real-world experience.
- 10% would wait for cardiovascular outcomes data.
- 8% would wait for payer coverage to be established.
Only 24% would prescribe immediately for appropriate patients.
The discontinuation discussion
A dermatologist and surgical oncologist on Sermo raised a problem almost no one else is talking about: “The real problem will be weaning patients off the agents when their ideal weight is reached, or convincing patients who are still losing weight that their agent must be stopped because it is harming some organ or metric they cannot see or feel.”
That is the discontinuation paradox, and it is one of the harder unresolved questions these drugs raise. How do you convince a patient that a drug working exactly as intended has to be stopped?
Shared decision‑making will require clear stopping rules (or maintenance dosing strategies), robust monitoring protocols, and honest discussion with your patients of the limited long‑term safety data. Payers, regulators, and guideline panels must also grapple with whether obesity treatment shifts from finite courses to lifelong management—because the way that the healthcare system resolves the discontinuation paradox will shape patient expectations, adherence, and outcomes for years to come.
Key takeaways
- Retatrutide posted the strongest Phase 3 weight loss results yet, 28.3% average at 80 weeks and up to 30.3% at 104 weeks in higher-BMI patients.
- Physicians on Sermo are optimistic about the science but cautious about practice, with 34% wanting Phase 3 outcome data before they commit.
- What would move physicians to prescribe is cardiometabolic proof, not the weight loss number, named by 36% as the benefit that matters most.
- The biggest barrier is structural, with 38% citing insurance and cost, not clinician willingness to prescribe.
- Most would prioritize obesity plus comorbidities (43%) over BMI alone, and approval is not expected until late 2027 at the earliest.
The bottom line on triple agonist therapy
Retatrutide looks like a real step change in obesity care, with TRIUMPH-1 showing optimistic weight loss results. TRIUMPH-4 went a step further, pairing that weight loss with real gains in joint pain, blood pressure, and lipids. However, getting from that data to routine prescribing still requires FDA review, payer coverage, new guidelines, and long-term safety monitoring, none of which moves quickly.
Physicians on Sermo are meeting all of this with measured optimism, trusting the science, and expecting cardiometabolic outcomes, not the weight-loss headline, to decide whether triple agonists earn a lasting place.
The TRIUMPH program keeps reporting through 2026 and Sermo is where verified physicians are already comparing notes on where these drugs fit, which patients come first, and how to get their practice ready. Join the community to follow the results and weigh in on where triple agonists belong.
