What are the side effects of GLP-1 weight loss medications?
The most common side effects of semaglutide and tirzepatide are nausea, constipation, diarrhea and reduced appetite, usually mild and worst in the first weeks and after dose increases. Less common are fatigue, reflux and injection-site reactions. Rare but serious risks include pancreatitis and gallbladder problems. They are not used in people with a personal or family history of medullary thyroid cancer.
Most side effects come from the medication doing its job: slowing digestion. Starting at a low dose and increasing gradually, eating smaller meals, and avoiding greasy food keep them manageable.
Tips that help
- Eat slowly and stop at the first sign of fullness
- Prioritize protein and fiber; stay hydrated
- Hold the dose increase an extra week if nausea is significant
- Report severe abdominal pain, vomiting or vision changes right away
Dr. Darvish monitors every patient in the medical weight loss program with regular check-ins so the dose can be adjusted to your tolerance.
Related
More about medical weight loss
How does a medical weight loss program work?
A medical weight loss program is physician-supervised weight loss using prescription medications such as semaglutide and tirzepatide (GLP-1 agonists), phentermine, phendimetrazine or Qsymia, alongside nutrition and lifestyle guidance and regular check-ins. After an evaluation and any needed labs, Dr. Darvish prescribes the medication that fits your health and goals and adjusts the dose over time. Read more
Semaglutide or tirzepatide: which is better for weight loss?
Tirzepatide (Mounjaro, Zepbound) produced greater average weight loss in clinical trials, around 20 percent of body weight versus about 15 percent for semaglutide (Ozempic, Wegovy), because it acts on two gut hormone receptors rather than one. Both are weekly injections with similar side effects, mainly nausea early on. Cost, availability, insurance and your health history often decide which is prescribed. Read more
How much weight can you lose on semaglutide or tirzepatide?
In clinical trials, patients lost an average of about 15 percent of their body weight on semaglutide and about 20 percent on tirzepatide over roughly 16 months, with some losing considerably more. Weight loss is gradual, typically one to two pounds per week after the first month. Results depend on dose, consistency, and the diet and activity changes made alongside the medication. Read more
What is Ozempic face and how do you fix it?
Ozempic face is the gaunt, hollow or sagging look that can follow rapid weight loss from GLP-1 medications, caused by loss of facial fat and reduced skin elasticity. It is corrected by restoring volume with Sculptra and hyaluronic acid fillers in the cheeks, temples and jawline, and by tightening the skin with Forma or Fractora. Slower weight loss and adequate protein reduce the effect. Read more
Phentermine or GLP-1 medication: which is right for me?
Phentermine is an oral appetite suppressant that is inexpensive, works quickly and is approved for short-term use; it is best for patients who need a modest, fast start and have no heart or blood pressure issues. GLP-1 injections like semaglutide and tirzepatide produce larger, more sustained loss and are safer long term. Dr. Darvish prescribes both and sometimes combines approaches. Read more