Mounjaro side effects: what the trials and the label say
Side-effect rates at each dose against a dummy injection, two Indian clinic studies, and when to get urgent help.
Written for India. Reading from the US? US versionComing soon
Mounjaro (tirzepatide) mostly causes stomach side effects: nausea, diarrhoea, vomiting, constipation and a smaller appetite. Most nausea, vomiting and diarrhoea came during dose increases and then decreased, say the US labels. Rarer serious risks include pancreatitis, gallbladder disease and kidney injury from dehydration. Low blood sugar is a risk with insulin or sulfonylureas.
Key takeaways
- Mounjaro's most common side effects are stomach-related; in the weight trials, nausea hit 25% to 29% of people on tirzepatide, against 8% on a dummy injection.2
- In the diabetes trials, nausea rose with the dose, from 12% at 5 mg to 18% at 15 mg, against 4% on a dummy injection.1
- Both US labels say most nausea, vomiting and diarrhoea came while the dose was being raised, and decreased over time.1,2
- Rarer serious risks on the US labels include pancreatitis, gallbladder disease, kidney injury from dehydration, and low blood sugar when taken with insulin or sulfonylureas.1,2
- In a Lucknow study of 71 adults with diabetes, 59% had stomach side effects; of 225 who started, 22% stopped within 3 months, often over stomach problems or cost.6
On this page
What are the most common side effects of Mounjaro injections?
Stomach and gut effects lead the list: feeling sick (nausea), diarrhoea, vomiting, constipation, indigestion, stomach pain and a smaller appetite.
- Mounjaro is prescription-only in India, and cannot be bought over the counter.14 More is in our Answer on GLP-1 prescriptions in India.
- A government statement on 1 Apr 2026 said only endocrinologists, internal-medicine specialists and cardiologists can prescribe GLP-1 medicines.14 CDSCO expert-committee minutes attach a similar condition to some approvals (endocrinologist or internal-medicine specialist), but we found no rule covering every brand.9
- All the risks of the medicine class are in Guide 5: Side effects and risks.
- Check for fakes and recalls in Guide 6.
- No dose guarantees any result, and side effects differ from person to person.
Mounjaro is tirzepatide, a weekly injection made by Eli Lilly. It was launched in India in March 2025 for diabetes and obesity.13 Cipla sells the same medicine under the name Yurpeak, and Lilly makes it.12 The medicine itself is explained in What is tirzepatide?, and its status here in Is Mounjaro available in India?
We found no public Indian label, so the figures here come from US labels. In the US, tirzepatide for weight loss is sold as Zepbound.2 Zepbound's label covers the weight trials, and Mounjaro's label covers the diabetes trials.1,2
The table pools the two main weight trials, SURMOUNT-1 and SURMOUNT-2. Together they gave 2,519 adults tirzepatide for up to 72 weeks, and 12% of all those enrolled were Asian.2 Others got a dummy injection (placebo), so the gap between columns shows what the medicine added.2
| Side effect | Placebo | 5 mg | 10 mg | 15 mg |
|---|---|---|---|---|
| Nausea | 8% | 25% | 29% | 28% |
| Diarrhoea | 8% | 19% | 21% | 23% |
| Vomiting | 2% | 8% | 11% | 13% |
| Constipation | 5% | 17% | 14% | 11% |
| Stomach pain | 5% | 9% | 9% | 10% |
| Indigestion | 4% | 9% | 9% | 10% |
| Injection-site reactions | 2% | 6% | 8% | 8% |
| Tiredness | 3% | 5% | 6% | 7% |
| Allergic-type reactions | 3% | 5% | 5% | 5% |
| Hair loss | 1% | 5% | 4% | 5% |
| Dizziness | 2% | 4% | 5% | 4% |
11 of the 16 side effects in the label's table: share of adults reporting each at least once, by weekly dose. The other 5 (burping, acid reflux, wind, bloating, low blood pressure) are in the full table in source 2. Source: Zepbound (tirzepatide) US label, Table 1, pooled SURMOUNT-1 and SURMOUNT-2, revised August 2026; checked 5 Oct 2026.2
Read it as people out of 100. At 15 mg, 28 in every 100 people had nausea, against 8 in 100 on placebo.2 That is 20 more people in every 100 (our arithmetic).
Most of the allergic-type reactions in the trials were skin reactions, such as rash and itching.2
The diabetes trials, SURPASS-1 and SURPASS-5, gave smaller figures in different people. Nausea hit 12% to 18% on Mounjaro, against 4% on placebo.1 Diarrhoea hit 12% to 17%, against 9%.1 In those two trials, 27% of the adults were Asian.1
A smaller appetite was reported by 5% to 11% in those trials, against 1% on placebo.1 In the diabetes trials, burping, wind and acid reflux were each reported by 3% or fewer.1 In the weight trials, burping and acid reflux reached 4% to 5%, against 1% to 2% on placebo.2
A wider pool of 7 diabetes trials gave 5,119 adults Mounjaro, and 24% of them were Asian. Its common side effects were similar to the smaller pool's.1
Do higher doses cause more side effects?
In the diabetes trials, yes: any stomach side effect rose from 37% at 5 mg to 44% at 15 mg, against 20% on placebo.
In the weight trials, the overall rate was 56% at every dose, against 30% on placebo.2 Within that, vomiting and diarrhoea still rose with dose, while constipation fell.2
More people stopped at higher doses. In the weight trials, stomach effects made 1.9% stop at 5 mg and 4.3% at 15 mg. On placebo, 0.5% stopped.2 In the diabetes trials it was 3.0% at 5 mg and 6.6% at 15 mg, against 0.4%.1
In SURMOUNT-1 alone, side effects made 4.3% to 7.1% of people on tirzepatide stop. On placebo, 2.6% stopped.4 Its stomach side effects were mostly mild to moderate and came mainly during dose increases.4
Severe stomach side effects hit 1.7% to 3.1% of people in the weight trials, against 1% on placebo.2 For a clinic seeing 100 people on 15 mg, that is about 3 severe cases (our arithmetic).
When do side effects start, and how long do they last?
Mostly in the first weeks and after each dose increase, according to both US labels, and most nausea, vomiting and diarrhoea then decreased.
The label starts everyone on 2.5 mg a week for 4 weeks. That dose is only a starting step, not a treatment dose.2 Each later step adds 2.5 mg after at least 4 weeks.1,2
The labels say this slow climb is there to lower the risk of stomach side effects.1,2 If a dose doesn't suit someone, the Zepbound label says a lower ongoing dose can be considered.2
An analysis of SURMOUNT-1 and SURMOUNT-2 found stomach effects were reported most in the first 8 weeks. Most were mild or moderate, and they fell over time.5 Lilly, which makes Mounjaro, funded that analysis.5
In the Lucknow clinic study, most nausea was mild and cleared within 2 to 3 weeks of starting.6 Most who quit for side effects in the weight trials did so in the first few months, over stomach effects.2
A short Answer on how long Mounjaro side effects last is on the way. What helps with nausea and constipation is in Guide 5.
A printable checklist on side effects, other medicines and follow-up. No sign-up.
What serious risks does the label list?
The US labels warn about pancreatitis, gallbladder disease, kidney injury from dehydration, severe allergy, bowel blockage and a thyroid tumour finding in rats.
- Pancreatitis (an inflamed pancreas): signs are severe stomach pain that won't go away, sometimes reaching the back, with or without vomiting.1 Diabetes trials confirmed it in 0.23 people per 100 treated for a year, against 0.11 on other treatments.1 The weight trials found 0.2% on both tirzepatide and placebo.2
- Gallbladder disease. Inflamed gallbladder (cholecystitis) hit 0.7% in the weight trials, against 0.2% on placebo. The label links it to weight loss.2 Signs include upper stomach pain, fever, yellow skin or eyes, and pale, clay-coloured stools.3
- Kidney injury. Sudden kidney injury hit 0.5% in the weight trials, against 0.2% on placebo.2 Reports since approval, for Mounjaro and similar medicines, show most cases followed dehydration from vomiting or diarrhoea. Some needed dialysis.1 Drinking fluids lowers the risk, says the medicine guide.3
- Severe allergy. Serious reactions with swelling (anaphylaxis, angioedema) have been reported after approval.1 In the weight trials, 0.1% had a severe allergic reaction, against none on placebo.2
- Bowel blockage. Reports since approval include a stopped or blocked bowel (ileus, obstruction) and severe constipation.1,2 The label does not recommend it for people with severe slow stomach emptying (gastroparesis).1
- Thyroid warning. Tirzepatide caused thyroid C-cell tumours in rats; whether it does in people is unknown.1 The US label rules it out if you or a relative had medullary thyroid cancer (MTC).1 The same goes for MEN 2, an inherited gland condition.1
- Eyes and heart. In people with diabetic eye disease (retinopathy), a fast fall in blood sugar can briefly worsen it.1 Heart rate rose by 2 to 4 beats a minute on average, against 1 on placebo.1
- Shared pens. A KwikPen must never be shared, even with a new needle, because it can pass on blood infections.1
More warning signs, and what doctors check, are in Guide 5's serious-risks section.
Can Mounjaro cause low blood sugar?
Rarely when used alone in trials, but the risk rises with insulin or sulfonylureas (diabetes pills that push the pancreas to release insulin).
Used alone for 40 weeks, nobody on Mounjaro had blood sugar below 54 mg/dL, against 1% on placebo.1 Added to long-acting insulin, 14% to 19% did, against 13% on placebo.1
With a sulfonylurea, over up to 104 weeks, 10% to 14% had blood sugar below 54 mg/dL.1 In a weight trial of people with diabetes, low sugar hit 10.3% of those on a sulfonylurea. It hit 2.1% of those not on one.2
In the Lucknow study, 31% of patients were on a sulfonylurea.6 Eight people (11%) had mild low sugar, and all of them were on a sulfonylurea or insulin.6
The label says a doctor may lower the dose of insulin or the sulfonylurea when Mounjaro starts.1 Signs of low sugar include shakiness, sweating, dizziness, hunger, confusion, a fast heartbeat and blurred vision.3 The type 2 diabetes path covers hypos in more detail.
Does Mounjaro affect the contraceptive pill or pregnancy?
Yes. It can make the pill less reliable, because it slows how fast the stomach empties, and the label warns about use in pregnancy.
The effect on stomach emptying is largest after the first dose and shrinks over time.1 So the label advises a switch to a non-pill method, or adding a barrier method such as condoms.1
That applies for 4 weeks after starting, and for 4 weeks after each dose increase.1 Hormonal methods that are not taken by mouth should not be affected.1
In animal studies, tirzepatide slowed growth and caused abnormalities in unborn young. Human data are too few to judge the risk.1 The Zepbound label says weight loss offers no benefit in pregnancy, and to stop it once a pregnancy is known.2
More is in Guide 4's pregnancy section and our coming post on GLP-1 medicines, pregnancy and the pill.
Why should your surgeon or anaesthetist know?
Food can stay in the stomach longer on Mounjaro, and rare cases of stomach contents entering the lungs under anaesthesia have been reported.
This is called pulmonary aspiration. The reports came from people on GLP-1 medicines having planned procedures under general anaesthesia or deep sedation.1 Some had food left in the stomach even after fasting as told.1
The label says there is not enough data to know whether longer fasting or pausing the medicine helps.1 It tells patients to inform every doctor before any planned surgery or procedure.1
Slower stomach emptying can also change how some tablets are absorbed. The label asks doctors to monitor medicines with a narrow safe range, such as the blood thinner warfarin.1
What have studies in Indian patients found?
Two clinic studies published in 2026 found nausea in 31% to 45% of people. One also counted semaglutide users, and neither had a placebo group.
Lucknow. Seven diabetes clinics reviewed records of adults with type 2 diabetes started on tirzepatide from April 2025.6 Of 225 who started, 71 had complete 3-month data.6
Among those 71, 59% had a stomach side effect. Nausea hit 45%, a smaller appetite 39%, diarrhoea 25%, stomach discomfort 20%, constipation 17% and vomiting 6%.6 No pancreatitis, gallbladder disease or kidney injury was seen in 3 months.6
Of the 225 who started, 50 (22%) stopped before 3 months.6 Stomach problems (18 people) and cost (16 people) were the top reasons.6 Six of the authors declared speaking fees from Eli Lilly.6
HbA1c (average blood sugar over about 3 months) fell from 8.7% to 6.9% in those 71. Weight fell by 4.7 kg on average.6 With no comparison group, the study can't show how much came from the medicine alone.6
- Stomach effects are common: nausea in 25% to 29% in the weight trials, against 8% on placebo.2
- Pancreatitis and gallbladder disease are rare but serious; inflamed gallbladder hit 0.7% vs 0.2%.2
- Dehydration from vomiting or diarrhoea can injure the kidneys.1
- Low blood sugar is more likely with insulin or sulfonylureas.1
- Thyroid warning: ruled out by the US label for anyone with a personal or family history of MTC or MEN 2; tell your doctor if this applies. Pregnancy: animal studies showed harm.1
New Delhi. Max Super Speciality Hospital, Saket, reviewed 150 adults: 117 (78%) on tirzepatide and 33 on semaglutide.7 Across all 150, nausea hit 31%, diarrhoea and constipation 25% each, bloating 14% and vomiting 11%.7
The paper found no significant difference between the two medicines, and gave no separate rates for each.7 Nobody had side effects severe enough to change or stop treatment.7 The authors declared no conflicts of interest.7
Trials and what's coming. SURMOUNT-1, the main weight trial, listed 6 Indian hospitals among its sites.10 CDSCO's expert committee recommended approval of tirzepatide in April 2023, on condition that Lilly run a Phase IV (after-approval) trial.9
In February 2026, Lilly registered a 46-week Phase 4 study of tirzepatide's safety in about 344 Indian adults. It is due to finish in July 2027.11
A 2026 review pooled the SURMOUNT trials and found side effects similar in Asian and mostly non-Asian trials.8 Only 148 Asian people got tirzepatide, too few to prove the rates are the same.8
How do you report a side effect in India?
Through the Pharmacovigilance Programme of India (PvPI): its helpline is 1800 180 3024, on working days from 9:00 am to 5:30 pm.15
PvPI also has a mobile app and a patient reporting form in Hindi and other Indian languages.15
Step-by-step reporting is in Guide 5. How Mounjaro's side effects compare with Ozempic's is in Mounjaro vs Ozempic. If you are already on Mounjaro, the already-on-it path lists the checks to make. GLP-1 itself is explained in our Answer on the GLP-1 full form.
Questions people ask
Does Mounjaro cause cancer?
Tirzepatide caused thyroid C-cell tumours in rats, but whether it does so in people is unknown. The US label rules it out if you or a relative had medullary thyroid cancer, or if you have MEN 2. Report a neck lump, hoarseness, trouble swallowing or breathlessness.1
Are Mounjaro side effects different for women?
Hair loss was more common in women: 7.1% of women on tirzepatide in the weight trials, against 0.5% of men. The label advises women on the contraceptive pill to switch method or add a backup method after starting and after each dose step.2,1
Does Mounjaro cause hair loss?
In the weight trials, 4% to 5% reported hair loss on tirzepatide, against 1% on placebo. The label links it to weight loss, and nobody on tirzepatide stopped because of it.2
What are the injection side effects of Mounjaro?
Injection-site reactions, such as redness, itching, bruising or pain, hit 6% to 8% in the weight trials. On placebo it was 2%. Allergic-type reactions, mostly rash and itching, hit 5%, against 3% on placebo.2
Does Mounjaro cause depression or mood changes?
The Zepbound US label once had a warning section on suicidal behaviour and thoughts. Its list of recent major changes shows that section was removed in February 2026. The Mounjaro US label has no such section.2,1
Can Mounjaro cause low blood pressure?
In the weight trials, low blood pressure hit 1.6% on tirzepatide, against 0.1% on placebo. It was more common in people on blood pressure medicines, and it also came with dehydration.2
How we researched this
On 5 October 2026 we read the US labels for Mounjaro and Zepbound (revised August 2026) and Mounjaro's medicine guide. We used US labels because we found no public Indian label.
Trial figures come from the labels' pooled tables, which regulators review, and from the SURMOUNT-1 paper. We read two Indian clinic studies in full, a 2026 review of Asian trials and the trial registry.
Indian context comes from CDSCO expert-committee minutes and a 1 April 2026 government backgrounder. We also used Cipla's launch release and a dated news report, and no pharmacy pages.
We could not find Indian side-effect data beyond 3 to 6 months, or any Indian trial with a placebo group. Results of Lilly's Indian Phase 4 study are not out yet.
Before you move on
- Stomach side effects are common, and mostly come during dose steps.
- Severe stomach pain, swelling or trouble breathing means calling 112.
- Low blood sugar is more likely on insulin or a sulfonylurea.
- On the pill, add a backup method after starting and after each dose step.
- Tell every doctor about Mounjaro before surgery or sedation.
More from the India blog
Ozempic side effects: which are common and which are serious?Coming soon
Mounjaro vs Ozempic: how do they differ in India?
Which weight-loss injections are approved in India?
The monthly India update
An independent guide to GLP‑1 medicines. We don't sell medicines, take drug-company money or earn clinic commissions. Once a month: new brands, price changes, approvals and recalls. How we write
Sources
- Eli Lilly. Mounjaro (tirzepatide) prescribing information, US label (no public Indian label found), revised August 2026: warnings 5.1–5.10, Tables 1–2 (SURPASS-1 and SURPASS-5 pool), drug interactions 7.1–7.2, pregnancy and contraception 8.1 and 8.3. PDF
- Eli Lilly. Zepbound (tirzepatide) prescribing information, US label, revised August 2026: dosing 2.1, warnings 5.2–5.7, Table 1 (SURMOUNT-1 and SURMOUNT-2 pool), pregnancy 8.1. PDF
- Eli Lilly. Mounjaro Medication Guide (US patient leaflet), revised August 2026: signs of pancreatitis, low blood sugar, allergy, dehydration and gallbladder problems. PDF
- Jastreboff AM, Aronne LJ, Ahmad NN et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). N Engl J Med 2022;387:205–16. Funded by Eli Lilly. DOI · PMID 35658024
- Kokkinos A, Thethi T, Lee CJ et al. Tirzepatide efficacy and tolerability according to early weight response: a post hoc analysis of the SURMOUNT-1 and SURMOUNT-2 trials. Diabetes Obes Metab 2026. Funded by Eli Lilly. DOI · PMID 42348366
- Chandra KP, Gupta M, Awasthi R et al. Real-world evidence of tirzepatide in Indian adults with type 2 diabetes (7 clinics, Lucknow). Cureus 2026;18(2):e102866. Declared interests: six authors report personal fees from Eli Lilly (paper's own declaration). DOI · PMID 41798487
- Jarso G, Mahendru S, Dutta A, Sharma R, Megerso A, Mithal A. Magnitude and determinants of weight loss response to GLP-1/GIP receptor agonists in India: a real-world time-to-event analysis (Max Super Speciality Hospital, Saket, New Delhi). Indian J Endocrinol Metab 2026;30(2):129–34. No conflicts declared. DOI · PMID 42238558
- Kamrul-Hasan ABM, Khalil I, Dutta D et al. Comparative efficacy and safety of tirzepatide in Asian and non-Asian adults with obesity without diabetes: a systematic review and meta-analysis. Endocrinol Diabetes Metab 2026. DOI · PMID 42487213
- CDSCO. Recommendations of the Subject Expert Committee (Endocrinology and Metabolism), 20–21 April 2023, item 1 (tirzepatide, Eli Lilly): India a participating country in the global Phase III trial; conditions on retail sale and a Phase IV trial. PDF · archived copy
- ClinicalTrials.gov. A study of tirzepatide (LY3298176) in participants with obesity or overweight (SURMOUNT-1), NCT04184622: study locations, including 6 in India. Link
- ClinicalTrials.gov. A Phase 4, open-label, single-arm, 46-week study to investigate the safety and efficacy with tirzepatide in adult Indian participants with either type 2 diabetes or obesity, NCT07438444. First posted 27 February 2026; estimated enrolment 344; estimated completion July 2027. Link
- Cipla. Cipla launches Yurpeak (tirzepatide) for the treatment of obesity and type 2 diabetes. Press release, 10 December 2025. PDF
- Business Standard. Eli Lilly launches blockbuster anti-obesity drug Mounjaro in India. 20 March 2025. Link
- Press Information Bureau (Government of India). GLP-1 drugs: use, risks, and regulation. Backgrounder, 1 April 2026. PDF
- Indian Pharmacopoeia Commission. Pharmacovigilance Programme of India: reporting adverse drug reactions (helpline, app, forms in Indian languages). Link
Last checked 5 Oct 2026 · Next review due 5 Oct 2027 · Report an error
How this post was made. Written by the GLP Guidebook team from the sources above. It's general information, not medical advice. Talk to a qualified doctor before starting, stopping or changing any medicine. How we write