Weight-loss injections, explained plainly.
Semaglutide (sold as Wegovy, Ozempic and several Indian makes) and tirzepatide (sold as Mounjaro and Yurpeak): what they are, how they work, how the doses go up, how much weight people lost in studies, the side effects, and what they cost in India.
Reviewed by Dr. Prabhat Arya, MBBS, MD (Internal Medicine)
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What these medicines are.
After a meal, the gut releases a hormone called GLP-1. It tells the brain you have eaten enough, slows the stomach so food stays longer, and helps the pancreas release insulin when sugar is high.
Semaglutide is a long-acting copy of GLP-1, strong enough to last a week. Tirzepatide copies GLP-1 and a second gut hormone, GIP, which seems to add to the effect.
People on them feel full sooner and think about food less. They eat less without the constant fight against hunger, and the weight comes off from that. They were first made for type 2 diabetes, which they also treat.
Which name is which.
Ozempic and Wegovy are the same medicine, semaglutide, in different doses for different uses. Mounjaro and Yurpeak are both tirzepatide.
| Medicine | Sold as | Taken | Approved in India for |
|---|---|---|---|
| Semaglutide injection | Wegovy; Ozempic; Indian makes since March 2026 | Once a week | Weight (Wegovy and some Indian makes); diabetes (Ozempic and others) |
| Tirzepatide injection | Mounjaro; Yurpeak | Once a week | Weight and diabetes |
| Semaglutide tablet | Rybelsus; Indian makes | Once a day | Diabetes only |
| Liraglutide injection | Saxenda (hard to find); Indian makes for diabetes | Once a day | Weight (Saxenda); diabetes (Indian makes). An older, weaker choice |
How the doses go up.
Every one starts low and goes up one step about every four weeks. The slow climb lets the stomach get used to it; most nausea comes in the days after a step up.
| Medicine | First four weeks | Then | Usual dose to stay on |
|---|---|---|---|
| Semaglutide injection for weight (Wegovy) | 0.25 mg | 0.5 mg, then 1 mg, then 1.7 mg | 2.4 mg once a week, from about week 17 |
| Semaglutide injection for diabetes (Ozempic) | 0.25 mg | 0.5 mg, then 1 mg | 0.5 to 2 mg once a week |
| Tirzepatide injection (Mounjaro, Yurpeak) | 2.5 mg | up by 2.5 mg at a time: 5, 7.5, 10, 12.5 mg | 5, 10 or 15 mg once a week |
| Semaglutide tablet for diabetes (Rybelsus) | 3 mg daily | 7 mg daily | 7 or 14 mg daily, on an empty stomach |
The injection goes under the skin of the tummy, thigh or upper arm, on the same day each week, with or without food. Your doctor may hold you at a lower step if it works well or the side effects are strong; you do not have to reach the top dose.
A missed dose can usually be taken within four days (tirzepatide) or five days (semaglutide); after that, skip it and take the next one on the usual day. Check your own medicine’s leaflet, or ask.
What the studies found.
In STEP 1, adults with obesity on semaglutide 2.4 mg lost on average 14.9 percent of their weight over 68 weeks, against 2.4 percent with the same advice and a dummy injection.
In SURMOUNT-1, adults on tirzepatide 15 mg lost on average 20.9 percent over 72 weeks, against 3.1 percent.
In SURMOUNT-5, the two compared directly: about 20 percent with tirzepatide and about 14 percent with semaglutide.
In SELECT, people with heart disease and overweight but no diabetes had 20 percent fewer heart attacks, strokes and heart deaths on semaglutide.
Side effects, honestly.
Common, and usually settling within weeks: nausea (in STEP 1, 44 in 100 people on semaglutide against 17 in 100 on the dummy injection), loose motions, constipation, vomiting, burping and acidity. Smaller meals, stopping when full and less fried food help.
Less common but serious: gallstones; inflammation of the pancreas (severe belly pain going through to the back); dehydration that strains the kidneys after a lot of vomiting; low sugar if you also take insulin or certain diabetes tablets; worsening of diabetic eye disease when sugar falls quickly; and, very rarely with semaglutide, a sudden loss of sight in one eye from the eye nerve.
Some of the weight lost is muscle. Protein at every meal and strength exercise protect it.
When you stop.
In the year after stopping semaglutide in STEP 1, people regained about two-thirds of the weight they had lost. In SURMOUNT-4, people who stopped tirzepatide after nine months regained about 14 percent of their weight, while those who carried on lost a further 5.5 percent.
So these medicines work while they are taken. The plan from the start should include how long, at what dose, and how to keep the weight off: food and activity habits built while the medicine makes them easier.
What they cost in India.
Monthly cost at the printed price, as listed by online pharmacies in October 2026. Prices have been falling since the generics came; check before you buy.
| Medicine | Per month | Note |
|---|---|---|
| Semaglutide, Indian makes | About ₹1,300 to ₹4,200 | Depends on the company and dose |
| Semaglutide (Wegovy) | About ₹5,700 to ₹16,400 | Rises with the dose; one pen lasts four weeks |
| Tirzepatide pen (Mounjaro, Yurpeak) | About ₹13,100 to ₹25,800 | Rises with the dose; one pen lasts four weeks |
| Semaglutide tablets (Rybelsus) | About ₹9,000 to ₹11,000 | Diabetes only |
Before you start.
India’s drug regulator has said these medicines are meant to be prescribed by specialists such as internal medicine physicians and endocrinologists.
A consultation looks at whether a medicine suits you at all, which one, and how to start: your BMI and waist, the illnesses that come with the weight, your other medicines, and the tests worth doing first, usually sugar (HbA1c), cholesterol, liver and kidney tests, and thyroid.
Then follow-up every few weeks while the dose goes up, to handle side effects and decide the next step.
Questions people ask.
Is Ozempic approved for weight loss in India?
No. In India Ozempic is approved for type 2 diabetes. Wegovy is the same medicine, semaglutide, in the doses approved for weight management. Several Indian companies now make semaglutide as well, since its patent ended in March 2026; some makes are approved for diabetes only.
What is the difference between Ozempic and Wegovy?
Both are weekly semaglutide injections from the same company. Ozempic goes up to 2 mg a week and is for diabetes. Wegovy goes up to 2.4 mg a week and is for weight management, and for lowering the risk of heart attack and stroke in people with heart disease.
Which works better, Mounjaro or semaglutide?
In the one study that compared them directly (SURMOUNT-5), people on tirzepatide (Mounjaro) lost about 20 percent of their weight over 72 weeks, and people on semaglutide about 14 percent. Which suits you also depends on your other illnesses, side effects, cost, and what is available.
Can I buy these medicines without a prescription?
No. They are prescription medicines. India’s drug regulator has said they are meant to be prescribed by specialists such as internal medicine physicians and endocrinologists, and it has warned about sales by gyms, slimming centres and unchecked online sellers. Fake Mounjaro pens have been seized near Delhi.
Are the Indian generic semaglutides the same?
They contain the same medicine and must meet the regulator’s standards. Brands differ in the pen, the dose steps available, the price, and whether they are approved for weight or only for diabetes. Your doctor can tell you which fits.
How soon does the weight start to come off?
Most people notice less hunger within the first weeks. Weight usually falls steadily for about a year, fastest in the first months, and then levels off.
Do I have to take it for life?
Not necessarily, but when it is stopped most of the lost weight usually returns within a year. Many people need it long term, as with a BP or diabetes medicine. Building the food and activity habits while on it helps keep the weight off.
Can I take it if I do not have diabetes?
Yes, if your BMI is in the range they are approved for: 30 or more, or 27 or more with a weight-related illness such as high BP, prediabetes, sleep apnoea or fatty liver. They are not meant for losing a few kilos at a healthy weight.
Will I lose muscle as well as fat?
Some of the weight lost is muscle, as with any weight loss. Enough protein at every meal and strength exercise two or three times a week protect it.
Are weight-loss tablets available in India?
Semaglutide tablets (Rybelsus and Indian makes) are sold for type 2 diabetes. A higher-dose semaglutide tablet and a new tablet, orforglipron, were approved for weight in the United States; as of October 2026 neither is on sale in India.
Where the numbers come from
- STEP 1: semaglutide 2.4 mg in adults with overweight or obesity (NEJM, 2021)
- SURMOUNT-1: tirzepatide in adults with obesity (NEJM, 2022)
- SURMOUNT-5: tirzepatide compared with semaglutide (NEJM, 2025)
- SELECT: semaglutide and heart attacks and strokes in people with heart disease (NEJM, 2023)
- STEP 1 extension: what happened in the year after stopping semaglutide (Diabetes, Obesity and Metabolism, 2022)
- SURMOUNT-4: continuing or stopping tirzepatide (JAMA, 2024)
- SCALE: liraglutide 3 mg for weight (NEJM, 2015)
Study numbers are averages. One person can lose more or less than the average, and studies are not a promise of any result.
Is a medicine right for you?
Dr. Arya goes through your weight, health and reports with you, explains the choices and their risks in plain words, and says plainly if a medicine is not the right step for you.
Book a video consultationDr. Prabhat Arya · MBBS, MD (Internal Medicine)