GLP-1 Weight Loss Medications Compared: 2026 Guide

By 2026 the question is no longer whether a GLP-1 medication produces weight loss. The pivotal trials settled that. The open question is which one, and the honest answer depends on figures that are easy to find and easy to misread. Several peptide medications now compete for the same prescription, their mean weight-loss numbers span roughly 6% to 22.5%, and a research-stage molecule has already cleared 28% in a Phase 3 readout. Comparing GLP-1 weight loss medications well means reading those numbers in the right order, then against the right person.

Several GLP-1 weight-loss medications now compete on the same prescription#

The useful starting point is the approved list, because most of what gets discussed under the "GLP-1 weight loss drugs" banner sits outside it. As of 2026 the FDA has approved four peptide-based medications for chronic weight management. Wegovy is semaglutide, a weekly GLP-1 receptor agonist, available as a 2.4 mg injection and, since the FDA cleared the oral 25 mg tablet with a US launch in early January 2026, as the first oral GLP-1 for weight loss. Zepbound is tirzepatide, a weekly dual agonist that activates both the GIP and GLP-1 receptors. Saxenda is liraglutide, a daily GLP-1 agonist that reached the market first and now sits at the lowest-effect end of the approved set.

What unites every one of these GLP-1 medications is the receptor they engage: each activates the GLP-1 receptor, and the differences sit in what else they do. The GLP-1 class explainer covers the receptor pharmacology in depth. This guide covers the comparison that follows from it, and it sits alongside the broader peptides for weight loss overview as the head-to-head reference.

Outside the approved perimeter sit two near-term arrivals, CagriSema and retatrutide, that already change the ceiling of what the trial data shows. They appear later in this comparison because they reframe the efficacy ladder, even though neither is approved yet.

Trial data ranks tirzepatide above semaglutide above liraglutide#

The published evidence on these medications is unusually clean, because the pivotal trials were randomised, double-blind, placebo-controlled, and reported a single hard endpoint: mean percent body-weight change at a fixed timepoint. The numbers are extractable in single sentences.

STEP 1 (Wilding et al., NEJM 2021, n=1,961) measured semaglutide 2.4 mg weekly against placebo. At 68 weeks the semaglutide arm lost a mean 14.9% of body weight versus 2.4% on placebo. SURMOUNT-1 (Jastreboff et al., NEJM 2022, n=2,539) measured tirzepatide at 72 weeks: 16.0% at 5 mg, 21.4% at 10 mg, and 22.5% at 15 mg. Liraglutide, by comparison, produced roughly 6% to 8% at 56 weeks in the SCALE program, which is why it now trails the weekly compounds.

The decisive evidence is the head-to-head. SURMOUNT-5 (Aronne et al., NEJM 2025, n=751) randomised adults with obesity to tirzepatide or semaglutide at their highest approved doses for 72 weeks. Tirzepatide produced a mean 20.2% reduction versus 13.7% for semaglutide, and nearly three times as many participants reached at least 30% loss. Studies have shown that adding the GIP axis to a GLP-1 agonist produces a meaningfully larger mean effect. The full secondary-endpoint reading sits in the semaglutide versus tirzepatide head-to-head guide, and the lowest-tier comparison is covered in the liraglutide versus semaglutide guide.

Medication	Receptor target	Trial dose	Mean weight loss	Duration	Trial
Liraglutide (Saxenda)	GLP-1	3 mg daily	~6-8%	56 wk	SCALE
Semaglutide (Wegovy)	GLP-1	2.4 mg weekly	14.9%	68 wk	STEP 1
Tirzepatide (Zepbound / Mounjaro)	GIP + GLP-1	15 mg weekly	22.5%	72 wk	SURMOUNT-1
CagriSema	amylin + GLP-1	2.4 / 2.4 mg weekly	22.7%	68 wk	REDEFINE-1
Retatrutide	GIP + GLP-1 + glucagon	12 mg weekly	28.3%	80 wk	TRIUMPH-1 (Phase 3, not approved)

The approved GLP-1 medications share one side-effect profile#

The comparison that matters most for tolerability is the one that finds the options are more alike than different. The dominant adverse-event profile across every GLP-1 weight-loss medication is gastrointestinal. Across the trials, pooled safety data put nausea in roughly 14% to 28% of participants, with vomiting and diarrhoea following, most events mild to moderate and most concentrated during dose escalation. The GI profile is the single largest driver of discontinuation, and it is the reason every label builds in a slow titration.

The serious warnings are also class-shared. The Wegovy label carries a boxed warning for medullary thyroid carcinoma based on rodent data, with human relevance undetermined, and the medications are contraindicated in anyone with a personal or family history of medullary thyroid carcinoma or MEN2. The labels also flag acute pancreatitis and gallbladder disease at low rates, and the class is contraindicated in pregnancy. Research suggests these GLP-1 side effects track the class rather than the individual molecule, so the safety comparison rarely decides between two approved options on its own.

Dosing, route, and titration separate the options more than efficacy does#

For many people the practical comparison is not the efficacy ladder but the schedule. Liraglutide is a daily injection. Semaglutide and tirzepatide are weekly injections. The oral semaglutide tablet is a once-daily option for anyone who wants to avoid needles, with the OASIS 4 trial reporting a mean 16.6% reduction at 64 weeks among adherent participants. Each option reaches its maintenance dose through a fixed titration ladder that exists to keep the GI events tolerable, which means the early weeks feel similar across the class even where the endpoints diverge.

For readers mapping the escalation, Klarovel's semaglutide dose calculator and tirzepatide dose calculator walk the weekly steps that the trial protocols built in.

In Norway, availability and reimbursement set the real choice#

The comparison narrows fast once it meets the Norwegian market. Wegovy and Mounjaro (the tirzepatide brand for weight management) are the marketed weight-loss options. Ozempic is approved for type-2 diabetes and is used off-label for weight, a distinction covered in the Ozempic versus Wegovy guide. According to FHI, more than 220,000 people in Norway used GLP-1 medications in 2024, roughly 148,000 of them for weight loss, and Mounjaro only launched in November 2024, so it is a recent market entrant rather than an established option.

Reimbursement is where the comparison gets decisive for cost. Saxenda lost individual blå resept coverage in early 2023, per Helfo. For Wegovy, a 2025 price offer led DMP to conclude the treatment is cost-effective for adults with a BMI of at least 35 and two or more weight-related conditions, and referred the reimbursement decision to the Ministry. The status is in flux rather than settled, so anyone weighing the options in Norway should confirm the current reimbursement position before treating cost as fixed.

The frontier raises the ceiling: CagriSema and retatrutide#

Two molecules already sit above the approved options on the efficacy ladder, which is why any current comparison has to name them. CagriSema combines the amylin analog cagrilintide with semaglutide. In the REDEFINE-1 trial it produced a mean 22.7% reduction at 68 weeks, though it fell short of its own pre-specified target, and the combination has been filed with the FDA. The amylin half of that story sits in the cagrilintide versus semaglutide guide.

Retatrutide goes further. The triple agonist adds glucagon-receptor activity to the GIP and GLP-1 axes, and in the Phase 3 TRIUMPH-1 readout reported in May 2026 it produced a mean 28.3% reduction at 80 weeks, rising further in the highest-BMI group. Retatrutide is not approved anywhere as of 2026, and a regulatory decision is still years out. The pattern across the frontier is consistent: each receptor added to the molecule corresponds to a larger mean effect, which is the same trend the approved ladder already shows. For the lipolysis-focused contrast, the AOD-9604 versus semaglutide guide covers a non-GLP-1 alternative that anchors the lower end of the evidence.

Choosing a GLP-1 starts with the health profile, not the ranking#

The efficacy ladder is the starting point of the comparison, not the answer to it. The best GLP-1 for weight loss on the trial ranking is tirzepatide among approved options, but the right choice depends on inputs the ranking cannot see. A cardiovascular history points toward the molecule with the strongest outcomes data. Needle aversion points toward the oral tablet. A tolerability history with one agonist may support trying another, and switching between GLP-1 medications is common and generally straightforward under supervision. The maintenance question applies to every option equally: stopping the medication tends to reverse the loss unless a durable lifestyle protocol is in place.

This is why a structured health profile, rather than a product name, is the honest first step. Klarovel's health questionnaire walks the contraindication screening, surfaces the maintenance question early, and lines up the comparison against the individual rather than against an average. The full regulatory framing for research-grade and off-label products sits in the Klarovel disclosures.

Each head-to-head below covers one comparison in depth: mechanism, the trial data behind it, dosing structure, and where the Norwegian regulatory line falls.

• AOD-9604 vs semaglutide: lipolysis vs satiety (2026): AOD-9604 vs semaglutide head-to-head: GH-fragment lipolysis against GLP-1 satiety.
• Cagrilintide vs Semaglutide: Two Pathways, One Decision (2026): Cagrilintide is an amylin analogue.
• CagriSema vs Semaglutide: Inside Novo Nordisk's Combo Bet: CagriSema pairs semaglutide with cagrilintide and hit 22.7% weight loss in REDEFINE 1.
• Liraglutide vs semaglutide: which GLP-1 wins?: Head-to-head on Saxenda vs Wegovy: dosing, weight loss, cardiovascular data, and tolerability.
• Ozempic vs Wegovy: What Actually Separates Them: Same molecule, different label.
• Semaglutide vs tirzepatide: the real head-to-head comparison: Semaglutide vs tirzepatide: a direct head-to-head trial settled the efficacy question.

The comparison that matters is the one against your own profile#

The class-level comparison is now stable enough to state plainly: GLP-1 receptor activity drives the largest mean weight-loss effects in the published literature, adding the GIP and glucagon axes raises the ceiling further, the approved options share one safety profile, and the maintenance question is structural rather than optional. What the cross-trial ranking cannot do is tell any one person which medication fits their history, their tolerance, and their market. That comparison is individual. Anyone weighing the options should start with a structured health profile and recent context, not with a SKU. Start with the Klarovel questionnaire to see which GLP-1 medication the evidence supports for the profile in front of it.