Semaglutide vs Tirzepatide and Newer Incretin Agonists

Compare semaglutide, tirzepatide, retatrutide, CagriSema, and orforglipron by receptor target, FDA status, trial design, outcomes, and evidence limits.

Semaglutide, tirzepatide, retatrutide, CagriSema, and orforglipron are often grouped under “GLP-1,” but they are not interchangeable. They differ in receptor targets, molecular form, regulatory status, trial populations, and the outcomes that have actually been measured.

This guide compares the evidence without turning separate trials into a leaderboard. Percent weight change from one study cannot be ranked fairly against another unless the populations, doses, durations, estimands, and comparators are sufficiently aligned.

Status snapshot

Status is current through August 29, 2026 and refers to the United States. An FDA approval applies to a specific product and indication, not automatically to every formulation or every molecule that activates the same receptor.

Compound	Primary target or targets	Form studied or marketed	U.S. status at review	Evidence anchor
Semaglutide	GLP-1 receptor	Peptide; injectable and oral products	FDA-approved products with indication-specific labels	STEP 1 weight-management trial; SELECT cardiovascular-outcome trial; FDA labeling
Tirzepatide	GIP and GLP-1 receptors	Peptide; once-weekly injection	FDA-approved products with indication-specific labels	SURMOUNT-5 direct comparison with semaglutide; SURPASS-CVOT
Retatrutide	GIP, GLP-1, and glucagon receptors	Investigational peptide; once-weekly injection in trials	Not FDA-approved; phase 3 and 3b research continues	Published phase 2 obesity trial; active TRIUMPH program
Cagrilintide with semaglutide (CagriSema)	Amylin pathway plus GLP-1 receptor	Investigational fixed-dose peptide combination; once-weekly injection in trials	Not FDA-approved at review; sponsor announced an NDA submission	REDEFINE 1 phase 3 trial; sponsor filing announcement
Orforglipron	GLP-1 receptor	Non-peptide small molecule; once-daily tablet	FDA approved as Foundayo on April 1, 2026, for a defined adult weight-management indication	ATTAIN-1 phase 3 trial; FDA approval and prescribing information

The status column is not a recommendation. It separates regulator-reviewed products from investigational programs so readers do not mistake a published trial, sponsor filing, or active phase 3 study for approval.

How the mechanisms differ

Semaglutide: GLP-1 receptor agonism

Semaglutide is a peptide analog engineered for longer exposure than native GLP-1. Its effects include glucose-dependent insulin secretion, glucagon regulation, appetite signaling, and altered gastrointestinal motility. Different semaglutide products have different formulations and approved uses; a brand name or route should not be generalized to every semaglutide product. See the GLP-1 physiology guide for the distinction between native hormone and receptor agonist.

Tirzepatide: dual GIP and GLP-1 receptor agonism

Tirzepatide activates both glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptors. It is not a “stronger semaglutide” or a higher-dose version of a GLP-1-only drug. Its dual-receptor pharmacology, approved labels, and clinical program must be evaluated on their own terms.

Retatrutide: triple GIP, GLP-1, and glucagon receptor agonism

Retatrutide adds glucagon receptor activity to GIP and GLP-1 receptor agonism. The phase 2 program produced substantial average weight reduction, but the molecule remains investigational. Phase 2 magnitude does not establish an approved benefit-risk profile, an appropriate clinical dose, or superiority over marketed products.

Cagrilintide and CagriSema: amylin plus GLP-1 pathways

Cagrilintide is a long-acting amylin analog rather than a GLP-1 receptor agonist. CagriSema combines cagrilintide with semaglutide, pairing amylin-pathway signaling with GLP-1 receptor agonism. Published phase 3 data support continued regulatory evaluation, but the combination had no FDA-approved label at this review date.

Orforglipron: oral, non-peptide GLP-1 receptor agonism

Orforglipron is a small molecule, not a peptide. It activates the human GLP-1 receptor and is taken orally. FDA approved it as Foundayo in April 2026 for chronic weight management in specified adults. Its approved dose, instructions, warnings, and adverse-reaction data come from its own label, not from injectable GLP-1 products.

What the weight-management trials measured

The table reports named trials rather than a cross-trial rank. Values are average changes for the specified population and analysis; they do not predict an individual response.

Trial	Population and comparison	Duration	Reported average body-weight change	What it can establish
STEP 1	Adults with obesity, or overweight plus a qualifying condition, without diabetes; semaglutide 2.4 mg vs placebo with lifestyle intervention	68 weeks	-14.9% with semaglutide vs -2.4% with placebo	Efficacy and safety of the studied semaglutide regimen against placebo in that population (Wilding et al.)
SURMOUNT-5	Adults with obesity without diabetes; maximum tolerated tirzepatide vs maximum tolerated semaglutide	72 weeks	-20.2% with tirzepatide vs -13.7% with semaglutide	A direct, randomized obesity-dose comparison of these two regimens; open-label design and the studied population still limit generalization (Aronne et al.)
Retatrutide phase 2	Adults with obesity, or overweight plus a qualifying condition; multiple retatrutide doses vs placebo	48 weeks	-24.2% in the 12 mg group vs -2.1% with placebo	Dose-ranging phase 2 signal and safety observations; not regulatory approval or a head-to-head comparison (Jastreboff et al.)
REDEFINE 1	Adults with obesity, or overweight plus a qualifying condition, without diabetes; CagriSema, semaglutide, cagrilintide, or placebo	68 weeks	-20.4% with CagriSema vs -3.0% with placebo under the treatment-policy estimand	Phase 3 efficacy and safety of the studied combination; not proof of FDA approval (Garvey et al.)
ATTAIN-1	Adults with obesity without diabetes; three orforglipron doses vs placebo	72 weeks	-7.5%, -8.4%, and -11.2% across studied doses vs -2.1% with placebo	Phase 3 efficacy and safety evidence supporting the product’s development; approved use is defined by the later FDA label (Wharton et al.)

Why these percentages should not be ranked

The retatrutide phase 2 value is sometimes described as “more weight loss” than results from other programs. That phrasing ignores major design differences:

Retatrutide was a dose-ranging phase 2 trial with 338 participants and 48 weeks of follow-up.
STEP 1, SURMOUNT-5, REDEFINE 1, and ATTAIN-1 used different populations, comparators, sample sizes, durations, dose-escalation rules, and statistical estimands.
An investigational high-dose arm is not equivalent to a regulator-selected marketed dose.
Trial completion, discontinuation, rescue interventions, and missing-data handling can change the reported average.

SURMOUNT-5 supports a direct statement only about the regimens and population it studied: maximum tolerated tirzepatide produced greater average weight reduction than maximum tolerated semaglutide at 72 weeks in adults with obesity without diabetes. It does not rank tirzepatide against retatrutide, CagriSema, or orforglipron.

Cardiovascular-outcome evidence

Weight change and cardiovascular outcomes are different endpoints.

Semaglutide: SELECT randomized adults with established cardiovascular disease and overweight or obesity, without diabetes. The primary cardiovascular event occurred in 6.5% of the semaglutide group and 8.0% of the placebo group (Lincoff et al.). Current Wegovy labeling includes a product- and population-specific cardiovascular indication.
Tirzepatide: SURPASS-CVOT compared tirzepatide with dulaglutide in people with type 2 diabetes and atherosclerotic cardiovascular disease. Tirzepatide met the trial’s noninferiority criterion for cardiovascular death, myocardial infarction, or stroke; it did not demonstrate superiority for that primary outcome (Nicholls et al.).
Retatrutide, CagriSema, and orforglipron: Weight-management efficacy trials are not substitutes for completed cardiovascular-outcome trials. Any cardiovascular claim should be tied to a named study, population, comparator, and endpoint rather than inferred from weight change alone.

Safety cannot be reduced to one score

The previous version of this page used plus signs to rank nausea, diarrhea, vomiting, and other effects. That representation hid dose, timing, discontinuation, population, and ascertainment differences.

Across the cited weight-management trials, gastrointestinal events were common and were often concentrated during dose escalation. That shared pattern does not make the safety profiles interchangeable. Product labels contain different dosing instructions, contraindications, warnings, interactions, reproductive guidance, and postmarketing information.

For approved products, use the current FDA documents:

For investigational compounds, the absence of a final label is itself important: phase 2 or phase 3 reports do not capture the full evidence review, approved dosing, manufacturing controls, or postmarketing surveillance that accompany approval.

A research-first comparison checklist

When reading an incretin comparison, check these questions in order:

Is the exact product FDA-approved for the stated use? Separate approval, submission, and trial status.
Which receptors does the molecule activate? GLP-1-only, dual, triple, and amylin combinations are different pharmacologic strategies.
Was the result placebo-controlled or head-to-head? A direct comparison supports a narrower conclusion than comparing two unrelated trials.
Who was studied? Diabetes status, cardiovascular disease, BMI criteria, age, and comorbidities affect applicability.
Which dose, duration, and estimand produced the number? A single percentage without this context is incomplete.
What outcome was measured? Weight, HbA1c, cardiovascular events, adverse events, and treatment discontinuation answer different questions.
Who funded the trial, and has the result been replicated? Sponsor-funded evidence can still be rigorous, but funding and replication remain part of interpretation.

Frequently asked questions

Which compound produced the greatest weight reduction?

There is no defensible five-way ranking from the trials above because most were not head-to-head. Retatrutide’s 12 mg phase 2 group had the largest numerical average in this set, but that does not prove superiority to approved products or other investigational programs.

Has tirzepatide been compared directly with semaglutide?

Yes. SURMOUNT-5 directly compared maximum tolerated obesity-management doses for 72 weeks in adults with obesity without diabetes. Tirzepatide produced greater average weight reduction in that trial. The result should not be generalized to different indications, doses, or populations without supporting evidence.