Mounjaro vs Ozempic, compared

What the two drugs actually are

Both are injections you give yourself once a week, and both work by imitating gut hormones that are released when you eat. They slow how fast the stomach empties, blunt appetite, and prompt the pancreas to release insulin when blood sugar is high. The difference is how many of those hormone systems each one touches.

Ozempic is semaglutide. It is a GLP-1 receptor agonist: it copies one hormone, glucagon-like peptide-1. Novo Nordisk has sold it in the US since 2017.

Mounjaro is tirzepatide. It acts on the GLP-1 receptor *and* the GIP receptor (glucose-dependent insulinotropic polypeptide) — a second gut hormone. Eli Lilly launched it in 2022. That dual action is the reason the head-to-head trial below came out the way it did.

Names cause most of the confusion here, so it is worth separating them once. Tirzepatide and semaglutide are the molecules. Mounjaro and Ozempic are the brand names those molecules carry when they are approved for type 2 diabetes. The same molecules are sold under Zepbound and Wegovy when approved for weight management, and a third category — compounded tirzepatide and compounded semaglutide — is made by pharmacies rather than by Lilly or Novo and is not FDA-approved at all.

What each one is approved to do

This is where the two labels differ most, and it is the part of the comparison that most articles skip. Both drugs treat type 2 diabetes. After that they diverge: Ozempic has picked up a cardiovascular indication and a kidney indication, while Mounjaro has picked up a pediatric indication and, in August 2026, a cardiovascular one of its own.

Prescribing either drug purely to lose weight is off-label use. It is legal, common, and a decision for a licensed clinician — but if weight is the reason you are asking, the on-label options are Zepbound and Wegovy, and a telehealth provider that sells you "Ozempic for weight loss" is describing an off-label prescription.

The one head-to-head trial: SURPASS-2

Almost every comparison of these two drugs stacks one drug's trial against the other's, which is not a comparison at all — different patients, different lengths, different baselines. There is one real exception, and it sits in Mounjaro's own FDA label.

SURPASS-2 randomised 1,879 adults with type 2 diabetes, all already taking metformin, to tirzepatide 5 mg, 10 mg or 15 mg, or to semaglutide 1 mg, for 40 weeks. Everyone started from a mean HbA1c of 8.3% and a mean weight around 93 kg.

Two honest caveats. The comparator was semaglutide 1 mg, and Ozempic's label now goes to 2 mg; in Ozempic's own 2 mg versus 1 mg trial the higher dose improved HbA1c by a further 0.2 points, which narrows the gap without closing it. And SURPASS-2 was a diabetes trial — weight was measured, but it was not the question being asked.

What each does to body weight

In SURPASS-2, people on tirzepatide lost more weight than people on semaglutide at every dose, and the difference grew with the dose: 1.9 kg at 5 mg, 3.6 kg at 10 mg, 5.5 kg at 15 mg. That is a real, measured, like-for-like difference — in people with type 2 diabetes, over 40 weeks, without any structured diet or exercise programme attached.

It does not settle the weight-loss question, because neither drug is studied for weight loss under these names. Those trials were run on the same molecules under different labels, in people without diabetes, for 68 to 72 weeks, with a 500-calorie daily deficit and 150 minutes of activity a week built into every arm including placebo.

In those trials, Zepbound (tirzepatide) 15 mg produced a mean weight reduction of 20.9% over 72 weeks, and Wegovy (semaglutide) 2.4 mg produced 14.9% over 68 weeks. Different trials, so the gap between those two numbers is an impression rather than a measurement — but they are the numbers the FDA reviewed, and the full table is on our weight-loss page.

One consistent finding across both: weight loss in people with type 2 diabetes is smaller. Zepbound 15 mg produced 14.7% in the diabetes trial against 20.9% without diabetes; Wegovy 2.4 mg produced 9.6% against 14.9%.

Side effects, warnings and who cannot take either

The side-effect profiles are close enough that tolerability is usually decided by the individual rather than by the drug. Both labels list nausea, diarrhea, vomiting, constipation and abdominal pain as the most common reactions, all more frequent as the dose rises.

• Both carry the same boxed warning. In rodents, both molecules caused dose-dependent thyroid C-cell tumors. Whether they do so in humans is unknown.
• Both are contraindicated in anyone with a personal or family history of medullary thyroid carcinoma, or with Multiple Endocrine Neoplasia syndrome type 2, and in anyone who has had a serious hypersensitivity reaction to the drug.
• Both warn about: acute pancreatitis; low blood sugar when combined with insulin or a sulfonylurea; serious allergic reactions; acute kidney injury caused by dehydration from vomiting or diarrhea; severe gastrointestinal reactions; gallbladder disease; and worsening of existing diabetic retinopathy.
• Tell any surgeon or anesthetist that you take one. Both labels warn about food being aspirated into the lungs during general anesthesia or deep sedation, because these drugs slow stomach emptying.
• Ozempic's label is more specific on one risk: in a two-year trial in people with type 2 diabetes and high cardiovascular risk, diabetic-retinopathy complications occurred in 3.0% on Ozempic against 1.8% on placebo, and in 8.2% against 5.2% among those who already had retinopathy.

This page summarises the labels; it is not a substitute for reading them or for a conversation with the clinician who would prescribe. The full documents are linked in the sources at the foot of this page.

Dosing, forms and how you take them

Both are injected under the skin of the abdomen, thigh or upper arm, once a week, at any time of day, with or without food. Both start low and step up, because the gastrointestinal side effects are worst when the dose rises too fast.

What each costs without insurance

Both manufacturers now sell direct to self-pay patients, and those prices are the floor against which every telehealth offer should be measured.

Mounjaro is $499 a month at every dose through LillyDirect — the price does not change as you titrate up. Ozempic is $199 a month for a new self-pay patient's first two fills at 0.25 mg or 0.5 mg, then $349 at 0.5 mg and 1 mg, and $499 at 2 mg, through NovoCare Pharmacy. Both also appear on TrumpRx at the same prices, which issues a coupon for the Novo products and hands Lilly orders to LillyDirect.

Against list prices of roughly $1,112 for Mounjaro and $1,027 for Ozempic, those are large reductions — and they are why a telehealth provider that adds a membership fee on top of the same manufacturer price is worth checking carefully. Our dated tables do that comparison for each drug: Mounjaro cost without insurance and Ozempic cost without insurance.

One pattern to know before you shop: across the providers we track, the cheapest Mounjaro offer sits more than $650 above LillyDirect's $499. For that drug in particular, buying direct is usually the cheaper route, and a provider's value has to come from the clinical service rather than the price.

Insurance changes the picture entirely. Both drugs are widely covered for type 2 diabetes and widely excluded for weight loss, and both manufacturers run copay programmes for commercially insured patients that these self-pay prices do not apply to.

Which one is right is not a question this page can answer

It is a prescribing decision, and the things that decide it are mostly about you rather than about the drugs. What the labels do tell you is which facts are worth raising in that conversation:

• Do you have chronic kidney disease? Ozempic is the only one of the two with an approved indication for slowing kidney decline in type 2 diabetes.
• Do you have established cardiovascular disease? Both now carry cardiovascular indications, but they rest on different evidence — Ozempic beat placebo, while Mounjaro was tested against another GLP-1 drug and was found non-inferior rather than superior.
• How much blood-sugar reduction do you need? SURPASS-2 favoured tirzepatide at 10 mg and 15 mg, with a wider dose range above it.
• How well did you tolerate the last escalation? Both labels tell prescribers to slow down rather than push through; nausea rises with dose on either drug.
• What will you actually pay, every month, for as long as you stay on it? A $150 monthly difference is $1,800 a year, and neither drug works after you stop taking it.
• Is the prescription being written by a clinician licensed in your state who has seen your history? That matters more than the choice between these two. Every provider profile on this site answers that question first.