GLP-1 Weight Loss Medications: Semaglutide Side Effects
Medically reviewed by Randall P. Brewer, MD, Medical Director.
GLP-1 medications such as semaglutide and tirzepatide can be effective tools for weight management, and most side effects are mild and short-lived. But it helps to know what’s common, what you can do about it, and which symptoms mean you should call your provider right away.
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This article is general information and doesn’t replace advice from your own provider. At Dixi’s MediSpa in Marshall, TX, patients in our physician-supervised program are monitored with monthly follow-up visits, and dose adjustments are made when appropriate.
Common side effects
The most frequently reported side effects of GLP-1 and GLP-1/GIP medications involve the digestive system, especially in the first weeks or after a dose increase:
• Nausea
• Diarrhea
• Constipation
• Vomiting
• Stomach pain or bloating
• Indigestion, belching, or heartburn
• Headache and fatigue
• Reduced appetite (which is part of how the medication works)
• Injection-site redness or irritation
These are usually manageable and improve over time.
Why do they happen?
These medications slow digestion and act on appetite signals in the brain. MedlinePlus has a plain-language explainer on GLP-1 agonists. Slower stomach emptying is part of why you feel full, and also why nausea or reflux can show up, especially when the dose goes up.
How to manage common side effects
Symptom | What often helps |
Nausea | Smaller meals, eat slowly, avoid very greasy or sugary foods, stop eating when you feel full |
Constipation | Water, fiber, movement; ask your provider before adding a laxative |
Diarrhea | Fluids and bland foods; call if it’s severe or lasts |
Heartburn or reflux | Smaller meals, avoid lying down right after eating |
Fatigue | Adequate protein and hydration; mention it at your visit |
Low appetite | Prioritize protein first, even when you’re not hungry |
When side effects are bothersome, tell your provider. Often the answer is to adjust the dose or pace, rather than to tough it out.
When to call your provider
Contact the clinic if you have:
• Vomiting or diarrhea that is severe, or that keeps you from keeping fluids down (dehydration can strain the kidneys)
• Persistent or severe stomach pain, especially if it spreads to your back, with or without vomiting. This can signal pancreatitis
• Pain in the upper right abdomen, fever, or yellowing of the skin or eyes. These can signal gallbladder problems
• A lump or swelling in the neck, trouble swallowing, or hoarseness that doesn’t go away
• Signs of low blood sugar if you take diabetes medicines: shakiness, sweating, confusion
• Vision changes
• Mood changes or thoughts of self-harm
When to get emergency help
Call 911 or go to the nearest emergency room for signs of a severe allergic reaction (swelling of the face, lips, or throat, trouble breathing, fainting) or severe, unrelenting abdominal pain.
Important safety information
Semaglutide and tirzepatide carry a boxed warning about the risk of thyroid C-cell tumors seen in animal studies. They are not used in people with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2. They are also not appropriate during pregnancy. Your provider reviews your history before prescribing. The FDA-approved labels for Wegovy (semaglutide) and Zepbound (tirzepatide) list the full boxed warning and contraindications.
Do side effects mean it isn’t working?
Not necessarily. Side effects and weight loss are separate things. Some people have few side effects and lose weight steadily; others feel more side effects early and settle. What matters is a plan with regular follow-up. The NIDDK also has a guide to prescription medications for overweight and obesity.
Frequently asked questions
How long do GLP-1 side effects last?
Early digestive side effects commonly improve over time and may come back briefly after a dose increase.
Do semaglutide and tirzepatide have the same side effects?
They share many, especially digestive ones. Your provider can explain differences relevant to you.
Can I take a GLP-1 if I’m pregnant or planning pregnancy?
No. Tell your provider if you are pregnant, planning to be, or breastfeeding.
Will I regain weight if I stop?
Weight regain is more likely if lifestyle changes are not maintained. Our program includes nutrition guidance and monthly check-ins.
Talk to our team
Dixi’s MediSpa: (318) 734-7086
Mon–Fri 9:00 AM–5:00 PM · Sat 9:00 AM–2:00 PM (every other Saturday, by appointment only)
Book a weight loss consultation
This article is for information and is not medical advice. Call your provider about any concerning symptom.
Sources: FDA prescribing information for Wegovy (semaglutide) and Zepbound (tirzepatide); MedlinePlus: GLP-1 agonists; NIDDK: prescription medications to treat overweight and obesity.
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