What to Expect When Starting Semaglutide or Tirzepatide?

Semaglutide and tirzepatide are 2 drugs that are frequently used to manage type 2 diabetes. Semaglutide is marketed as either Ozempic or Wegovy and tirzepatide is marketed as either Mounjaro or Zepbound. They are excellent glucose lowering drugs and may also lower blood pressure. They also typically lower weight, reduce appetite and food cravings, with higher doses usually causing more weight loss. Most importantly they reduce long term risks of heart attacks, strokes, heart failure, kidney disease and even death.

When starting one of these drugs it’s important to remember several things:

1. Everything that medicine knows about any drug is based on studies that show what it does on average to the average person. No individual is an average person and so it’s impossible to predict beforehand how any one person will respond, how much their blood sugar will go down, how much weight they will lose (if any), or any other effect. That’s why the drug is started at a low dose, and patients are advised to increase it slowly. This allows both patients and their healthcare providers to get a sense of how they are individually responding.
2. The drug works on the brain, the stomach, the gut, and other parts of the body. At the stomach, it slows emptying during a meal. This makes many people feel full after only a few bites and can sometimes cause nausea and rarely vomiting. That’s why it’s important to slow the speed of eating when starting one of these drugs and to stop eating when feeling full.
3. About 1 in 5 people complain of loose bowel movements, diarrhea, or constipation. This tends to get better after a few months but it’s important to be aware of it.
4. The drugs don’t cause hypoglycemia themselves. However, if people are taking insulin or a sulfonylurea drug, the gentle lowering of glucose by either semaglutide or tirzepatide might reduce the need for insulin or a sulfonylurea. Therefore, doses of insulin or sulfonylureas may need to be reduced to avoid hypoglycemia if it emerges after starting semaglutide or tirzepatide. Occasionally blood pressure drug doses might need to be reduced as well to avoid light headedness because both semaglutide and tirzepatide generally lower blood pressure.
5. Whenever someone loses weight, whether by diet, bariatric surgery, or with a drug like semaglutide or tirzepatide, muscle tends to be lost along with the weight. That’s because lighter people need less muscle to move their body than heavier people, so muscle tends to be lost along with weight. Staying as active as possible after starting semaglutide or tirzepatide can help maintain muscle strength and muscle mass.

Drugs like semaglutide or tirzepatide have truly revolutionized diabetes care. Although they are generally safe and have both short- and long-term health benefits, they are prescription drugs and are powerful. Only Health Canada approved versions of these drugs, and they should only be used under the guidance of one or more qualified healthcare professionals.

About the author

Hertzel Gerstein

Hertzel is an endocrinologist and professor at McMaster University who is in high demand as a speaker, advocate, and educator on diabetes-related topics. His research focuses on using large, international randomized trials to identify and test new ways of preventing type 2 diabetes, reducing serious health outcomes like strokes and death, and achieving type 2 diabetes remissions.