Version July 2025
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Can medicines help with weight loss? —
Sometimes. Prescription weight loss medicines work by reducing your appetite or by changing the way you digest food.
If you want to lose weight, start by talking to your doctor or nurse. They can help you make a plan to do this in a healthy way. The first step is to make changes to your diet and exercise habits. Sometimes, doctors recommend medicines in addition to these changes.
Doctors use a measure called "body mass index," or "BMI," to help understand a person's weight. Your BMI tells you which category you are in based on your weight and height (figure 1). Your doctor might recommend medicine if you have not been able to lose weight in other ways and you:
●Have a BMI of 30 or greater, or
●Have a BMI between 27 and 29.9, and also have a weight-related medical problem, like diabetes, heart disease, or high blood pressure
If you are interested in trying medicine for weight loss, talk to your doctor or nurse. They can help you understand the benefits and risks.
What are the different weight loss medicines? —
When doctors prescribe medicines for weight loss, they most often choose "GLP-1" medicines. These usually come as shots that go under the skin. They were originally used in treating diabetes. But they can also help with weight loss in some people without diabetes. Examples include:
●Tirzepatide (sample brand names: Zepbound, Mounjaro)
●Semaglutide (sample brand names: Wegovy, Ozempic)
●Liraglutide (sample brand name: Saxenda)
These medicines do not all work exactly the same way. But they all affect a hormone called GLP-1. They increase the amount of insulin your body releases after eating. (Insulin is a hormone that helps control your blood sugar level.) They also slow digestion and make you feel full more quickly.
For people who cannot take the above medicines, doctors sometimes recommend other medicines that come as pills. Examples include:
●Phentermine-topiramate (brand name: Qsymia)
●Naltrexone-bupropion (brand name: Contrave)
●Orlistat (brand names: Xenical)
●Phentermine (brand names: Adipex-P, Lomaira)
Do weight loss medicines cause side effects? —
Yes. All these medicines can cause side effects.
Side effects depend on the medicine. For example, the incretin-based (GLP-1) medicines can cause nausea, vomiting, diarrhea, and constipation. The other medicines can also have other side effects.
Talk to your doctor about your medicine's possible side effects. You should also read all the information that comes with your prescription.
Can I reduce the cost of weight loss medicines? —
Many weight loss medicines can be expensive. There are sometimes ways to lower the cost. For example, you can check the medicine company's website. They sometimes offer ways to buy the medicine from them directly, instead of getting it from a pharmacy.
Be careful about companies or websites offering "compounded" versions of weight loss medicines. These have risks. For example, they do not have to meet the same safety and quality requirements as other medicines.
If you are worried about cost, or if you have questions about other ways to get your medicine, ask your doctor or nurse.
What else should I know?
●Weight loss medicines can be a helpful part of treatment for some people. But even if your doctor does prescribe medicine, they will also still recommend making lifestyle changes. This can help improve your overall health.
●For most medicines to work, you probably need to keep taking them long term. Otherwise, you will likely gain back the weight you lose.
●If you take medicine that can cause weight gain to treat a health condition, your doctor can work with you to try to find one that will not cause weight gain. This can be an important part of a weight loss plan.
●Be careful about herbs and supplements that claim to help with weight loss. Many of these products do not work, and some are unsafe. Check with your doctor or pharmacist before you take any non-prescription ("over-the-counter") medicines for weight loss.
Patient education: Weight loss treatments (The Basics)
Patient education: Understanding body mass index (BMI) (The Basics)
Patient education: Losing weight through diet (The Basics)
Patient education: Health risks of obesity (The Basics)
Patient education: How to use an autoinjector (The Basics)
Patient education: How to use a pen injector (The Basics)
