This article outlines the common, expected side effects, less common but serious reactions, and what to do if side effects interfere with your daily life.
Common Side Effects of Ozempic
Most side effects are mild, tend to occur early in treatment, and often settle over time—especially once your dose stabilizes [2].
1. Gastrointestinal (GI) Symptoms
These are the most frequently reported [2, 3]:
- Nausea
- Vomiting
- Constipation
- Diarrhoea
- Abdominal discomfort or cramps
- Bloating or gas
- Heartburn or acid reflux
- Burping (often with an odd taste)
These occur because Ozempic slows down how quickly food moves through your stomach—a mechanism that helps with weight loss but can temporarily upset digestion [1, 2].
Tip: Eating smaller meals, avoiding greasy or spicy foods, and staying hydrated may reduce GI symptoms.
2. Headaches or Dizziness
A small number of users report headaches or feeling lightheaded, especially during the dose adjustment phase [1].
3. Fatigue
Some people feel more tired or sluggish than usual when first starting Ozempic, but this often resolves [2].
Less Common but Serious Side Effects
While rare, these side effects may be more serious and require prompt medical attention [1, 3].
1. Pancreatitis
Symptoms: Severe, persistent stomach pain (may spread to the back), nausea, and vomiting [3].
What to do: Stop the medication and contact your doctor immediately if suspected.
2. Gallbladder Issues
Includes gallstones or gallbladder inflammation.
Symptoms: Pain in the upper right abdomen, nausea, fever, or yellowing of the skin (jaundice) [1, 2].
3. Low Blood Sugar (Hypoglycemia)
More common if used with other diabetes medications like insulin or sulfonylureas [1].
Symptoms: Shaking, sweating, dizziness, confusion, or fast heartbeat.
4. Kidney Issues
Dehydration from vomiting or diarrhoea can stress your kidneys [3, 4].
Important to stay well hydrated, especially in the early stages of treatment.
5. Allergic Reactions
Symptoms: Rash, itching, swelling of the face or throat, severe dizziness, or difficulty breathing [3].
Note: These are rare but require emergency care if they occur.
Boxed Warning: Thyroid C-Cell Tumors
Ozempic carries an FDA boxed warning about a possible risk of medullary thyroid carcinoma, a rare form of thyroid cancer. This risk has mostly been seen in animal studies and has not been confirmed in humans [3].
Avoid Ozempic if you have a personal or family history of:
- Medullary thyroid cancer (MTC)
- Multiple Endocrine Neoplasia syndrome type 2 (MEN2)
If you develop a lump or swelling in the neck, hoarseness, trouble swallowing, or persistent throat discomfort, see your doctor.
Mental Health and Mood Changes
Some people have reported mood changes or thoughts of self-harm while taking GLP-1 medications like Ozempic [2].
Notify your healthcare provider if you or your loved ones notice:
- Persistent low mood
- Unusual behavioral changes
- Suicidal thoughts
When Do Side Effects Happen?
Most side effects occur when starting the medication or increasing the dose [1, 4].
- Your body usually adjusts within a few weeks.
- Some providers use a step-up dosing schedule to minimize these effects (e.g., starting at 0.25 mg weekly before increasing) [3].
When to Call Your Doctor
Call your doctor if you experience:
- Persistent nausea or vomiting
- Severe stomach pain
- Yellowing of the skin or eyes
- Rapid heartbeat
- Swelling of the face or throat
- Mood changes or thoughts of self-harm
What You Can Do to Feel Better
- Stay hydrated: Especially if you have nausea or diarrhoea.
- Eat mindfully: Avoid overeating and choose foods that are gentle on your stomach.
- Rest: Allow your body time to adjust.
- Track your symptoms: Note when they occur and what may trigger them.
Final Thoughts
Ozempic can be a powerful tool in managing type 2 diabetes and supporting weight loss, but being informed about its side effects is key to using it safely [1]. Most side effects are manageable and improve with time, but always speak to your healthcare provider if something doesn’t feel right.
Do not stop taking Ozempic without consulting your doctor.
References
- Jeong D, Priefer R. Anti-obesity weight loss medications: Short-term and long-term use. Life Sci. 2022;295:120403. doi:10.1016/j.lfs.2022.120403
- Phillips A, Clements J. Clinical review of subcutaneous semaglutide for obesity. J Clin Pharm Ther. 2022;47(8):1233–1240. doi:10.1111/jcpt.13679
- FDA Prescribing Information for Ozempic (semaglutide). U.S. Food and Drug Administration. Updated 2023.
- Australian Medicines Handbook. Semaglutide. 2023 edition.