Mounjaro: what it's approved for in the US and how it compares

If you've read that Mounjaro is a weight-loss drug, you've probably been reading a UK page. In the US, Mounjaro is a type 2 diabetes drug, full stop. The same molecule, tirzepatide, carries a separate US weight label under the name Zepbound. That split affects your insurance, your price and what your prescriber can write, so it's worth getting straight.

Mounjaro is tirzepatide for type 2 diabetes

Mounjaro is the type 2 diabetes brand of tirzepatide, a weekly injection that activates both the GIP and GLP-1 receptors. The label says it “enhances first- and second-phase insulin secretion, and reduces glucagon levels, both in a glucose-dependent manner” ^[1]. In plain terms, it helps your body release more insulin when blood sugar is high, and less sugar-raising glucagon.

It does more than that. The label also says tirzepatide increases insulin sensitivity, delays stomach emptying and “decreases food intake, and reduces body weight in patients with type 2 diabetes mellitus.” The molecule-wide story is on our tirzepatide page.

Mounjaro is approved for blood sugar and heart risk in type 2 diabetes

The Mounjaro label lists two uses. It improves blood sugar control, alongside diet and exercise, in adults and children 10 and older with type 2 diabetes. And it reduces the risk of cardiovascular death, heart attack or stroke in adults with type 2 diabetes “who are at high risk for these events” ^[1].

Is Mounjaro for diabetes or weight loss? In the US, diabetes. People with type 2 diabetes often lose meaningful weight on it, and that's a welcome effect, but it isn't an approved use on its own. Our Zepbound vs Mounjaro comparison shows exactly where the two labels split.

Mounjaro beat semaglutide 1 mg on blood sugar and weight

In SURPASS-2, adults with type 2 diabetes already on metformin had their A1C fall 2.01 to 2.30 points on Mounjaro, against 1.86 points on semaglutide 1 mg, over 40 weeks. They also lost 4.2 to 12.1 pounds (1.9 to 5.5 kg) more weight ^[11]. The trial was open-label and funded by Eli Lilly.

The heart-risk approval deserves a careful read. SURPASS-CVOT compared Mounjaro with dulaglutide, an older GLP-1 drug already shown to lower heart events, not with placebo. Heart attacks, strokes and cardiovascular deaths occurred in 12.2% vs 13.1%. That met the bar for being no worse than dulaglutide but missed the bar for being better ^[12].

Mounjaro is now approved for children 10 and older with type 2 diabetes

The December 2025 approval rests on SURPASS-PEDS, a 30-week trial of 99 young people 10 and older with type 2 diabetes, most already on metformin. Their average age was 15. Mounjaro 5 mg and 10 mg both lowered A1C more than placebo ^[1]. The label caps the dose at 10 mg a week for children.

Side effects in the young group were mostly similar to adults', with more vomiting, abdominal pain and low blood sugar. Vomiting hit 16% on 5 mg and 12% on 10 mg, against 3% on placebo. The label also says the KwikPen isn't recommended for children to inject on their own.

In the US, Mounjaro for weight loss alone is off-label

In the US, using Mounjaro for weight loss without type 2 diabetes is off-label; Zepbound is labeled for it. Labels differ by country, which is why some overseas pages describe Mounjaro as a weight-loss medicine. A US prescriber can still write Mounjaro off-label, but insurance rarely covers it that way, and there's no price advantage: LillyDirect lists Mounjaro higher than Zepbound.

Mounjaro causes weight loss by reducing how much people eat

Mounjaro leads to weight loss because people eat less. The label says tirzepatide “decreases food intake” and reduces body weight in type 2 diabetes, and delays stomach emptying, most after the first dose ^[1]. Zepbound's label, for the same molecule, adds that it “decreases calorie intake,” likely “by affecting appetite,” with more fat lost than lean mass ^[2].

Does Mounjaro burn fat directly? Neither label describes that. In SURPASS-2, people with diabetes on tirzepatide lost several kilograms more than those on semaglutide 1 mg ^[11]. In people without diabetes on Zepbound, losses reached 20.9% at the top dose over 72 weeks ^[13]. People with type 2 diabetes generally lose less on these drugs than people without it.

Mounjaro comes in four forms, and the label sets a start and a maximum

Mounjaro comes as a single-dose pen, a single-dose vial, a four-dose multi-dose vial and a four-dose KwikPen, in strengths from 2.5 to 15 mg ^[1]. The label's recommended starting dose is 2.5 mg once a week, and its maximum is 15 mg a week for adults and 10 mg for children 10 and older. Your prescriber sets the steps in between based on blood sugar. Tirzepatide's half-life is about five days, which is what makes weekly dosing work.

Storage is in the label too. Pens and vials are kept refrigerated, and a single-dose pen or vial can be kept unrefrigerated, at no more than 86°F, for up to 21 days in total; multi-dose vials and KwikPens allow 30 days at room temperature ^[1]. Ask your pharmacist how your form should be handled.

Is there a Mounjaro pill? No. Mounjaro is only an injection, taken once a week with or without food. Lilly's GLP-1 pill, Foundayo, is a different drug approved for weight, not type 2 diabetes. If you've seen “microdosing Mounjaro” mentioned, that means taking less than the label's doses; it hasn't been tested, and our guide to microdosing tirzepatide explains why.

Most side effects are stomach-related, and most happen early

The label lists nausea, diarrhea, decreased appetite, vomiting, constipation, indigestion and abdominal pain as the side effects seen in at least 5% of people ^[1]. Stomach side effects hit 37.1% to 43.6% of people on Mounjaro against 20.4% on placebo, and the label says most nausea, vomiting and diarrhea occurred while the dose was being raised and eased over time.

The boxed warning is about thyroid C-cell tumors in rodents; Mounjaro is ruled out for anyone with a personal or family history of medullary thyroid carcinoma or MEN 2. Other warnings cover pancreatitis, low blood sugar with insulin or sulfonylureas, kidney injury from dehydration, severe stomach reactions (not recommended in severe gastroparesis), gallbladder disease, diabetic eye complications and aspiration during anesthesia. It can also make birth-control pills less reliable for four weeks after starting and after each dose increase.

More detail: is Mounjaro safe, does Mounjaro make you pee more and the molecule-wide tirzepatide side effects guide.

Mounjaro is usually added to metformin, not swapped for it

Can Mounjaro replace metformin? That's a prescriber decision, and the label doesn't describe Mounjaro as a replacement. In SURPASS-2, everyone was already taking metformin, and Mounjaro was added on top ^[11]. Many people with type 2 diabetes take both.

The two work differently. Metformin mainly lowers the glucose your liver releases. Mounjaro acts on gut-hormone receptors, boosts insulin when it's needed, slows digestion and curbs appetite. Our metformin vs Ozempic comparison covers the same question for the closest GLP-1 alternative.

Other type 2 diabetes drugs in the same family

What can you take instead of Mounjaro for type 2 diabetes? Several other approved drugs act on the GLP-1 receptor. The list below is alphabetical and uses label facts only. Which one fits is a conversation with your prescriber.

Is Mounjaro the same as Ozempic? No. Mounjaro is tirzepatide, which acts on two receptors; Ozempic is semaglutide, which acts on one. Head to head in SURPASS-2, Mounjaro lowered A1C and weight more. See Ozempic vs Mounjaro and Wegovy vs Mounjaro.

Mounjaro self-pay starts at $499 a month, more than Zepbound

LillyDirect lists Mounjaro at “starting at $499/month” for every strength from 2.5 to 15 mg, and says terms apply ^[9]. Zepbound, the same drug, starts at $299 for the 2.5 mg vial or KwikPen ^[10]. With insurance, Mounjaro is more often covered, because type 2 diabetes coverage is more common than obesity coverage.

Use the monthly cost calculator to compare a program's billing with these maker prices.

You need a prescription, and a type 2 diabetes diagnosis for on-label use

Mounjaro needs a prescription. LillyDirect asks your doctor to send it to LillyDirect Pharmacy, and points people without a prescriber to outside virtual diabetes care ^[9]. A few telehealth programs list brand Mounjaro:

Also offered by (no standing monthly price published): WellorithmPartner, Ivím Health.

Compounded tirzepatide isn't Mounjaro and isn't FDA-approved; the basics are on the compounded tirzepatide page. For how GLP-1 telehealth works in general, read our telehealth guide.