Tirzepatide

Mounjaro and Zepbound

As of August 2026, the US Mounjaro label covers blood-sugar control and reduction of major cardiovascular-event risk in specified people with type 2 diabetes. The Zepbound label covers long-term weight reduction in specified adults and moderate-to-severe obstructive sleep apnea in adults with obesity.^34,37

Who the trials studied

SURMOUNT-1 and -4 enrolled adults with obesity, or overweight plus a weight-related complication. SURMOUNT-5 enrolled adults with obesity. These trials excluded diabetes. SURMOUNT-OSA required obesity and moderate-to-severe sleep apnea. SUMMIT required obesity and heart failure with ejection fraction at least 50%. SURPASS-CVOT enrolled people with type 2 diabetes and established cardiovascular disease.^{32,11,33,34,35,36}

How the trials were run

The main studies here were funded by the manufacturer. SURMOUNT-5 was open label. SURMOUNT-4 randomized only people who completed and tolerated a 36-week tirzepatide lead-in.^{32,11,33,35,36}

Weight loss trials

SURMOUNT-1 was placebo-controlled. SURMOUNT-5 was a separate, open-label comparison with semaglutide.

Tirzepatide 5 mg		15%
Tirzepatide 10 mg		19.5%
Tirzepatide 15 mg		20.9%
Placebo		3.1%

% of starting body weight. Once-weekly subcutaneous treatment. 2,539 adults with obesity, or overweight plus a complication, without diabetes. Treatment-regimen estimand; all groups received lifestyle intervention.³²

Average weight loss

Mean weight changed by -15.0%, -19.5%, -20.9% and -3.1%. These randomized-group results cover 72 weeks and do not forecast one person's result. Gastrointestinal events were the most common adverse events. Eli Lilly funded the study.³²

Tirzepatide		20.2%
Semaglutide		13.7%

% mean body-weight loss at week 72. Once-weekly subcutaneous treatment. 751 adults with obesity and no type 2 diabetes; maximum tolerated tirzepatide 10 or 15 mg versus semaglutide 1.7 or 2.4 mg.¹¹

After stopping

In SURMOUNT-4, everyone first received tirzepatide for 36 weeks. The trial then randomized people to continue tirzepatide or switch to placebo.

-5.5% vs +14.0%

Participants who continued tirzepatide lost another 5.5% on average; those switched to placebo regained 14.0% on average. The between-group difference was -19.4 percentage points (95% CI -21.2 to -17.7).³³

Who reached randomization

The trial put 783 people into an open-label lead-in at the maximum tolerated dose. After that period, only 670 people reached randomization and were assigned to continue tirzepatide or switch to placebo. The result applies most directly to people who completed and tolerated the lead-in.³³

Heart and sleep apnea

The trials measured cardiovascular events, sleep apnea and heart failure in high-risk groups.

12.1% vs 13.0%

In the current FDA label analysis, MACE-3 occurred in 803/6,647 people assigned to Mounjaro and 863/6,647 assigned to dulaglutide. Hazard ratio 0.92 (95.3% CI 0.83-1.01). The trial met noninferiority to dulaglutide. Superiority was not shown.³⁴

The August 2026 Mounjaro label reports both the cardiovascular indication and the active-comparator result. It approves use to reduce major cardiovascular-event risk in adults with type 2 diabetes at high risk; the trial did not show superiority to dulaglutide.³⁴

-20.0 and -23.8 events/hour

At week 52, the estimated differences in apnea-hypopnea index were -20.0 and -23.8 events per hour across two placebo-controlled trials. Trial 1 enrolled people who were not using positive airway pressure at baseline. Trial 2 enrolled people who were using it. Together, the trials randomized 469 adults.³⁵

The sleep-apnea results apply to adults with both obesity and moderate-to-severe OSA. They do not answer mild OSA or OSA without obesity. The current US Zepbound label covers this group.^35,37

9.9% vs 15.3%

Cardiovascular death or worsening heart failure occurred in 36/364 people assigned to tirzepatide and 56/367 assigned to placebo. Hazard ratio 0.62 (95% CI 0.41-0.95). Everyone had ejection fraction at least 50% and BMI at least 30.³⁶

Fewer worsening-heart-failure events drove the composite: 8.0% versus 14.2%. Cardiovascular death alone was 2.2% versus 1.4%, hazard ratio 1.58 (95% CI 0.52-4.83). This trial did not show lower cardiovascular mortality.³⁶

Safety

This page covers selected findings from the August 2026 Zepbound label. The full label has all warnings, interactions and details for specific groups.

Zepbound 5 mg		25%
Zepbound 10 mg		29%
Zepbound 15 mg		28%
Placebo		8%

% of participants. Pooled Studies 1 and 2 in adults with obesity or overweight. These are descriptive label rates for the pooled groups.³⁷

Stopping because of side effects

Adverse reactions caused permanent discontinuation in 4.8%, 6.3% and 6.7% of people taking Zepbound 5, 10 and 15 mg, versus 3.4% with placebo. Most stopped during the first months because of gastrointestinal reactions.³⁷

Serious warnings

The boxed warning covers thyroid C-cell tumors in rats; the relevance to people is unknown. Zepbound is contraindicated with a personal or family history of medullary thyroid carcinoma, MEN 2, or a prior serious allergic reaction. Other warnings cover severe gastrointestinal reactions, kidney injury from fluid loss, gallbladder disease, pancreatitis, serious allergic reactions, low blood sugar with insulin or an insulin secretagogue, diabetic-retinopathy complications, and pulmonary aspiration during anesthesia or deep sedation.³⁷

These are current US label statements.³⁷

Common questions about tirzepatide

Regulatory details are current to September 28, 2026 unless another date is shown.

01 Are Mounjaro and Zepbound the same drug?

Mounjaro and Zepbound contain the same active ingredient, tirzepatide, but they are separate US products. Under the August 2026 labels, Zepbound is approved for long-term weight management and moderate-to-severe obstructive sleep apnea in adults with obesity. Mounjaro is approved for blood-sugar control in adults and children age 10 and older with type 2 diabetes, and to reduce major cardiovascular-event risk in adults with type 2 diabetes at high risk. Their instructions and approved uses are not interchangeable.^37,34

02 Is there an approved tirzepatide pill?

The current US Mounjaro and Zepbound labels cover injections under the skin and include no oral tirzepatide product. A pill may be developed later. A product sold now as oral or sublingual tirzepatide should not be called an approved Mounjaro or Zepbound form without a matching regulator record.^37,34

03 Is tirzepatide banned in tested sport?

WADA lists tirzepatide as monitored in and out of competition in its official 2026 material. It is not prohibited. The 2027 Monitoring Program keeps it in that category in its 2027 edition. Monitoring tracks use and does not itself create a doping violation. Athletes still need to check the current rules and exact product because an unapproved or compounded product may contain undeclared substances.^38,39,40

04 Is losing about 21% guaranteed?

No. The 20.9% result was the group average in the SURMOUNT-1 15 mg arm at 72 weeks. The trial included adults with obesity, or overweight plus a complication, who did not have diabetes. Everyone received lifestyle support. Results differed among people and across the 5, 10 and 15 mg groups.³²

05 Was weight loss different in people with type 2 diabetes?

In SURMOUNT-2, adults with overweight or obesity and type 2 diabetes lost 12.8% on average with 10 mg and 14.7% with 15 mg, versus 3.2% with placebo at 72 weeks. Those averages were lower than in SURMOUNT-1, which excluded diabetes. Because the trials enrolled different groups, they cannot show that diabetes caused the difference.^41,32

06 Did tirzepatide prevent type 2 diabetes in people with prediabetes?

In the three-year SURMOUNT-1 prediabetes group, 1.3% of people taking tirzepatide and 13.3% taking placebo developed type 2 diabetes over 176 weeks. Seventeen weeks after treatment stopped, the figures were 2.4% and 13.7%. This was a 1,032-person subset of the obesity trial among people with prediabetes. By itself, it does not create a separate prevention indication.^42,37

07 What did the direct semaglutide comparison actually show?

SURMOUNT-5 found 20.2% average weight loss with tirzepatide and 13.7% with semaglutide at 72 weeks in 751 adults with obesity and no type 2 diabetes. It compared the highest tolerated doses, was open label and was funded by tirzepatide's manufacturer. This is a direct comparison for that group and those dose ranges.¹¹

08 Has tirzepatide been compared directly with retatrutide?

No completed head-to-head result was available. TRIUMPH-5 is registered to compare retatrutide with tirzepatide in adults with obesity, but its primary completion was still pending. Results from separate trials cannot show which drug is better for the same person.⁴³

09 Does lean-mass loss mean the same amount of muscle loss?

No. The scan used in this study measured lean mass rather than skeletal-muscle mass or strength directly. In the 160-person SURMOUNT-1 substudy, fat mass fell 33.9% and lean mass fell 10.9%. About 75% of lost weight was fat mass and 25% was lean mass.⁴⁴

10 Can a lower maintenance dose preserve some weight loss?

SURMOUNT-MAINTAIN studied people who had first taken a maximum tolerated 10 or 15 mg dose for 60 weeks. At week 112, weight was 21.9% below the original baseline in those continuing that dose, 16.6% below baseline in those assigned 5 mg, and 9.9% below baseline in those switched to placebo. In the reported rescue analysis, 60 of 90 placebo participants (67%) received rescue tirzepatide. The placebo result therefore includes people who restarted active treatment.⁴⁵

11 Do withdrawal studies prove that tapering prevents regain?

No. After a 36-week lead-in, SURMOUNT-4 compared continued maximum tolerated tirzepatide with a switch to placebo. After a longer lead-in, SURMOUNT-MAINTAIN compared the continued maximum tolerated dose, 5 mg and placebo. Neither trial randomized a tapering schedule, microdosing, cycling or intermittent use.^33,45

12 Does the sleep-apnea result mean positive airway pressure can be stopped?

No general rule to stop PAP came from these trials. SURMOUNT-OSA had two trials. One enrolled people who were not using PAP, and the other enrolled people who were using it at baseline. Tirzepatide improved apnea-hypopnea index in both, but a decision about PAP depends on the person's sleep study and clinician.^35,37

13 Is tirzepatide approved specifically for HFpEF?

No separate HFpEF approval was in place. SUMMIT was positive in people with obesity and HFpEF, but the current US labels do not list HFpEF as a separate use. EMA also did not add one in January 2026; it added the data to the product information. Fewer worsening-heart-failure events drove the favorable composite, not fewer cardiovascular deaths.^36,37,34,46

14 Does a better liver biopsy mean liver failure was prevented?

No. SYNERGY-NASH measured MASH resolution and fibrosis improvement on biopsy after 52 weeks in people with F2 or F3 fibrosis. It did not show prevention of liver failure, transplant or death. MASH was not an approved tirzepatide use in the current US labels.^47,37,34

15 How can Mounjaro have a cardiovascular indication if superiority was not established?

SURPASS-CVOT compared tirzepatide with dulaglutide, an active comparator with its own cardiovascular indication. The primary endpoint showed noninferiority rather than superiority. FDA approved Mounjaro on August 27, 2026 to reduce cardiovascular death, nonfatal heart attack and nonfatal stroke in adults with type 2 diabetes at high risk. The trial randomized 13,299 people. The FDA label table includes 13,294 who received treatment; the paper's modified intention-to-treat analysis includes 13,165. Each figure refers to a distinct analysis group.^48,34

16 Did SURPASS-CVOT also prove kidney protection?

An exploratory analysis found major kidney events in 6.0% of the tirzepatide group and 7.6% of the dulaglutide group, with a hazard ratio of 0.77. Participants had type 2 diabetes and atherosclerotic cardiovascular disease. The analysis was planned in advance, but kidney outcomes were exploratory. It compared tirzepatide with another medicine, and the current Mounjaro label does not include a separate kidney indication.^49,48,34

17 How common are nausea and treatment-stopping side effects?

In pooled Zepbound weight-management trials, nausea occurred in 25%, 29% and 28% of people taking 5, 10 and 15 mg, versus 8% with placebo. Adverse reactions caused 4.8%, 6.3% and 6.7% to stop treatment, versus 3.4% with placebo. Gastrointestinal reactions caused much of the difference. These tirzepatide rates apply to the named doses and study group.³⁷

18 Can tirzepatide cause pancreatitis?

Yes. The labels warn about acute pancreatitis, including postmarketing hemorrhagic or necrotizing cases that were sometimes fatal. In pooled Zepbound weight trials, adjudicated pancreatitis occurred in 0.2% with tirzepatide and 0.2% with placebo. An OSA pool had a higher exposure-adjusted rate with tirzepatide. Rare events and postmarketing reports cannot set a precise personal probability or support a zero-risk claim. Severe, lasting abdominal pain needs urgent assessment.^37,34,50

19 Does the boxed warning mean tirzepatide is known to cause thyroid cancer in people?

No human cause has been established. Tirzepatide caused thyroid C-cell tumors in rats, and the labels say its relevance to people is unknown. The products are contraindicated for people with a personal or family history of medullary thyroid carcinoma or MEN2. Trial follow-up is not long enough to rule out a rare risk that takes years to appear.^37,34

20 How common was hair loss in the weight trials?

In pooled Zepbound weight-management trials, hair loss occurred in 5%, 4% and 5% of people taking 5, 10 and 15 mg, versus 1% with placebo. Among people taking tirzepatide, the label reports 7.1% in women and 0.5% in men and links the event with weight loss. Those figures give trial-group frequency; they cannot identify one cause or predict permanence for one person.³⁷

21 Do FAERS or compounded-product reports prove tirzepatide caused an event?

No. FAERS collects reports of suspected side effects. This analysis compared reporting patterns; event rates among everyone taking the medicine were outside its scope. FDA had received more than 730 reports associated with compounded tirzepatide as of May 31, 2026. FDA says it cannot always tell whether the drug caused an event or other factors contributed.^14,51

22 Is compounded tirzepatide still legal after the shortage ended?

Compounded tirzepatide is not FDA-approved. In 2026, FDA proposed excluding tirzepatide from the list of bulk substances outsourcing facilities may use under section 503B. The cited notices describe a proposal and an extended comment period; they do not establish a final rule.^14,52,53,54

23 Is research-use-only tirzepatide the same as Zepbound or Mounjaro?

No equivalence has been shown. Zepbound and Mounjaro are approved finished products with specific labels, forms and manufacturing controls. FDA has warned sellers of unapproved tirzepatide marked research use only, described dosing errors and counterfeits, and can stop noncompliant GLP-1 active ingredients at the border. Identity, strength, sterility and clinical equivalence require more than a chemical name on a vial.^14,55,37,34

24 Have counterfeit Mounjaro pens been found?

Yes. In February 2026, MHRA warned about falsified Mounjaro KwikPen 15 mg products. The alert documents that specific counterfeit event without estimating how common counterfeits are in every market. Check authenticity through the relevant regulator, a licensed pharmacy and the exact batch details in the alert rather than by appearance alone.⁵⁶

25 What do the approved 2.5 to 15 mg steps mean, and can milligrams be converted to syringe units?

The US labels give doses in milligrams for specific ready-to-use products. They start at 2.5 mg weekly, then allow 2.5 mg increases at least four weeks apart. Maintenance doses depend on the product and use. The August 2026 Mounjaro label describes increases when more blood-sugar control is needed. Milligrams are drug amount; milliliters are volume; syringe units depend on concentration and device. Without the exact approved product or pharmacy label, a general chart is not reliable and should not be used for a research vial.^37,34,14

26 What does the label say about birth control and pregnancy?

Tirzepatide delays stomach emptying. The US labels say oral hormonal birth control may work less well for four weeks after treatment starts and four weeks after each dose increase. They advise switching to a non-oral method or adding a barrier method during those periods. Zepbound says weight loss is not recommended during pregnancy and to stop when pregnancy is recognized.^37,34

27 What should the procedural team know before anesthesia or deep sedation?

The labels report rare cases of lung aspiration after people received GLP-1 medicines during general anesthesia or deep sedation, even when they followed fasting instructions. They do not give one stop interval for every person and procedure. The labels say patients should give the anesthesia or procedure team the exact product, dose timing, symptoms and other medicines, then follow the current plan.^37,34

28 Does tirzepatide reduce alcohol cravings?

The cited studies report completed experiments in rodents, with no established benefit in people. A randomized phase 2 trial in people with schizophrenia and alcohol use disorder was recruiting and had no posted results in its registry record.^57,58,59