GLP-1 Side Effects: How to Ease Nausea, Constipation and Fatigue
Nausea, constipation and tiredness are the most common side effects of semaglutide and tirzepatide. Here's why they happen, simple ways to ease them, and when to call your provider.
Published 2026-11-13 by Avere Beauty
Most people who start semaglutide or tirzepatide notice something in their stomach in the first few weeks. That's normal, and in most cases it's manageable. The same thing that makes these medications work, slowing digestion and quieting hunger, is what causes the most common side effects.
Here's what to expect and the simple changes that help most.
Written by the Avere Beauty weight loss team · November 2026
Why side effects happen
GLP-1 medications slow how quickly your stomach empties, so food stays with you longer. That's why you feel full sooner. But if you eat the way you used to (big portions, rich food, eating fast), your stomach can feel overloaded. Side effects are usually strongest right after you start or move up to a higher dose, and they often ease as your body adjusts.
That's also why every good program starts low and goes slow. At Avere, your nurse practitioner raises your dose step by step and checks in weekly, so we can slow down if your body needs more time.
Nausea
- Eat smaller meals. Stop at the first sign of fullness, not when the plate is empty.
- Slow down. Put your fork down between bites. Fullness signals take a few minutes to arrive.
- Go easy on greasy, fried and very sweet foods. They sit heavier and are the most common trigger.
- Don't lie down right after eating. Give yourself a couple of hours.
- Keep bland options on hand: crackers, toast, rice, broth, applesauce.
- Sip water steadily instead of drinking large amounts at once.
Constipation
- Drink more water than you think you need. Eating less often means drinking less too.
- Add fiber gradually: berries, pears, beans, oats, vegetables and chia seeds.
- Move every day. Even a short walk after meals helps things along.
- Ask before you take anything. Your provider can tell you which over-the-counter options are a good fit for you.
Diarrhea
Keep up your fluids, choose simple foods for a day or two, and limit greasy food, dairy and sugar alcohols (common in "sugar-free" snacks). If it lasts more than a couple of days or you feel lightheaded, let your provider know.
Feeling tired
Fatigue usually comes from eating much less than before, especially too little protein and too little water. Aim for protein at every meal, stay hydrated and keep moving. Our guide to what to eat on semaglutide or tirzepatide covers easy ways to get enough protein when your appetite is small.
When to call your provider right away
Most side effects are mild, but some need attention. Contact your provider right away, or call 911 in an emergency, if you have:
- Severe stomach pain that won't go away, with or without vomiting, especially if it spreads to your back
- Vomiting you can't stop or being unable to keep fluids down
- Signs of dehydration: dizziness, a racing heart, or very little urine
- Pain in the upper right side of your belly, fever, or yellowing of your skin or eyes
- Swelling of your face, lips or throat, or trouble breathing
These medications aren't right for everyone. They aren't used in people with a personal or family history of medullary thyroid cancer or MEN 2, or during pregnancy. That's one reason we review your full health history before prescribing.
You don't have to push through it alone
Side effects are one of the main reasons people stop GLP-1s early. Having a provider who checks in every week makes a real difference. At Avere, your nurse practitioner can adjust your dose, slow down increases, or talk through another option like Contrave if a GLP-1 isn't a good fit.
Frequently asked questions
What are the most common side effects of semaglutide and tirzepatide?
The most common side effects are stomach-related: nausea, diarrhea, constipation, vomiting, burping and stomach discomfort. Many people also feel more tired in the first weeks. They're usually strongest when you start or raise a dose and often ease as your body adjusts.
How long does GLP-1 nausea last?
For many people, nausea is worst in the first few days after starting or increasing a dose and settles within a few weeks. If it doesn't, your provider can slow down dose increases or keep you at a lower dose longer.
What helps with nausea on a GLP-1?
Smaller meals, eating slowly, stopping at the first sign of fullness, avoiding greasy or very rich food, and sipping water through the day help most people. Bland foods like crackers, toast and broth can help on harder days.
When should I call my provider about side effects?
Call right away for severe or ongoing stomach pain (especially pain that spreads to your back), vomiting you can't stop, signs of dehydration such as dizziness or very little urine, pain in the upper right belly, or any allergic reaction. For an emergency, call 911.
This article is general education, not medical advice. Weight loss medication is prescribed only after a provider reviews your health history, and results vary from person to person.
Ready to talk it through? Book a $50 weight loss consultation, call 412-952-7592, or read how our program works.
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