Mounjaro vs Ozempic: Which Works Better for Weight Loss?

Mounjaro led to more weight loss than Ozempic’s medicine in the only head-to-head trial: about 20% of body weight against 14% over 72 weeks. Both are weekly injections with similar stomach side effects, so the right choice depends on your health, how you cope with the dose increases, and cost. Here is how Mounjaro injection and Ozempic compare.¹

What’s the difference between Mounjaro and Ozempic?

Both copy gut hormones that tell your brain you are full and slow down your stomach. The difference is how many hormones they copy:

• Ozempic contains semaglutide, which copies one hormone, GLP-1. Wegovy is the same medicine, licensed for weight loss.²
• Mounjaro contains tirzepatide, which copies two hormones, GLP-1 and GIP.³

Both are once-a-week pens injected into the tummy, thigh or upper arm. Both start low and rise slowly: Ozempic from 0.25 mg, Mounjaro from 2.5 mg, with steps at least four weeks apart.^2,3

Mounjaro vs Ozempic: which works better for weight loss?

Mounjaro, in the only trial that compared them directly. SURMOUNT-5 followed 751 adults with obesity but without diabetes for 72 weeks, each on the highest dose they could manage:¹

• Weight lost: 20.2% of body weight on tirzepatide, against 13.7% on semaglutide.
• Waist: 18.4 cm smaller, against 13.0 cm.
• Bigger losses: more people on tirzepatide lost at least 15%, 20% and 25% of their weight.

One honest limit: the trial was open-label, so people knew which medicine they had, and it was funded by tirzepatide’s maker. Still, a gap of about 6 percentage points is large. For someone weighing 90 kg, that’s roughly 5–6 kg more on average. Results vary a lot between people.

Mounjaro vs Ozempic side effects

The side effects are much alike. In SURMOUNT-5 the most common ones on both were stomach problems, mostly mild to moderate and mainly during dose increases.¹ Each medicine’s label lists these rates from its own weight-loss trials:^2,3

• Nausea: 28% on tirzepatide 15 mg, 44% on semaglutide 2.4 mg.
• Diarrhoea: 23% and 30%.
• Vomiting: 13% and 24%.
• Constipation: 11% and 24%.

Read these with care. They come from different trials, with different people and dosing schedules, so they don’t prove that one causes less nausea. About 5–7 in 100 people stopped either medicine because of side effects.^2,3

Which is safer, Mounjaro or Ozempic?

They carry the same main warnings. Both can cause pancreatitis and gallbladder problems, rarely. Both caused thyroid tumours in rodents, so neither is used if you or a close relative has had medullary thyroid cancer. And neither is used in pregnancy.^2,3 Our guide to Ozempic side effects explains the warning signs.

Two differences are worth knowing:

• Heart evidence: semaglutide has a large heart trial. In 17,604 people with heart disease and excess weight, it cut heart attacks, strokes and heart deaths from 8.0% to 6.5% over about three years.⁴
• The pill: tirzepatide can make birth-control pills less reliable. Use a barrier method as well, or a non-pill method, for 4 weeks after starting and after each dose increase.³

Mounjaro vs Ozempic price in Pakistan

At our clinics, Ozempic costs from Rs 45,000 a month. We quote the Mounjaro price at your free consultation, because it depends on the dose your doctor prescribes. Lower-cost options contain the same active medicines, made by other pharmaceutical companies: tirzepatide injection from Rs 12,495 a dose, and semaglutide injection from Rs 6,995 a dose. Prices are the same at all 12 clinics, and you can compare every weight loss injection price in Pakistan in one place.

Which one should you choose?

Mounjaro may suit you if you want the biggest average weight loss shown in trials, and you don’t rely on the pill for contraception (or can switch).

Ozempic may suit you if you have heart disease, you rely on the pill for contraception, or you want the medicine with the longest track record.

Either way, the injection works best with eating and activity changes, and the weight tends to return if you stop. After stopping semaglutide, people regained about two-thirds of their lost weight within a year.⁵ In a tirzepatide trial, people who stopped regained 14% of their weight, while those who carried on lost a further 5.5%.⁶

Questions people ask

Is Mounjaro stronger than Ozempic?

For weight loss, yes on average: 20.2% against 13.7% in the head-to-head trial. “Stronger” doesn’t mean better for everyone, though. The right medicine is the one you can stay on.

Can I switch from Ozempic to Mounjaro?

Yes, with a doctor’s plan. Never use the two together. Your doctor chooses the starting dose of the new medicine and how fast to raise it.³

Which has fewer side effects?

Both mainly cause stomach side effects during dose increases. The labels show lower rates for tirzepatide, but those come from separate trials, so they can’t settle the question.

Do you need a prescription?

Yes. Both are prescription medicines for adults whose weight affects their health. Buy only from a licensed pharmacy or clinic: DRAP has warned about fake weight-loss pens.⁷

Get a doctor’s view

Weight-loss consultations are free at all 12 of our clinics. A doctor checks your BMI, health and medicines, explains which injection suits you and its full cost, and follows you up at each dose step. See Mounjaro in Islamabad or Ozempic in Karachi, or message us on WhatsApp and we reply.

Medically reviewed by Dr Sadaf Saleem, Dermatologist, FCPS (Dermatology), PM&DC 62494-P; Dr Junaid Rabbani, Dermatologist, PM&DC 44510-S; and Dr Shegref Mushtaq, Dermatologist, FCPS (Dermatology), PM&DC 19827-N

1. Aronne LJ, et al. Tirzepatide as compared with semaglutide for the treatment of obesity (SURMOUNT-5). N Engl J Med, 2025.
2. US National Library of Medicine. WEGOVY (semaglutide) injection: prescribing information. DailyMed.
3. US National Library of Medicine. ZEPBOUND (tirzepatide) injection: prescribing information. DailyMed.
4. Lincoff AM, et al. Semaglutide and cardiovascular outcomes in obesity without diabetes (SELECT). N Engl J Med, 2023.
5. Wilding JPH, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension. Diabetes Obes Metab, 2022.
6. Aronne LJ, et al. Continued treatment with tirzepatide for maintenance of weight reduction in adults with obesity (SURMOUNT-4). JAMA, 2024.
7. Drug Regulatory Authority of Pakistan. Rapid Alert I/S/07-23-24: suspected falsified GLP-1 receptor agonists. 2023.

Treatments in this article

Sessions, downtime and results for each, on its own page.

Mounjaro Injection for Weight LossAppointment: A few seconds per injection · Downtime: None; nausea is common at firstOzempic & Wegovy InjectionsAppointment: Under a minute, at home · Downtime: None; tummy upset early onTirzepatide InjectionAppointment: A 30-minute visit; the injection takes seconds · Downtime: None; nausea is common at first

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