Bad Side Effects of Weight Loss Therapies (Ozempic, Mounjaro, Saxenda, and Bariatric Surgery) - Updated 2025

If you're considering weight loss therapies, it's important to understand both their benefits and the potential side effects. While these treatments can help with significant weight loss, they come with risks that should be carefully considered. Below is a summary of the bad side effects associated with the most commonly used weight loss therapies: Ozempic (semaglutide), Mounjaro (tirzepatide), Saxenda (liraglutide), and Bariatric Surgery.


Ozempic (Semaglutide)

Ozempic is a medication that has been approved for weight loss in addition to its use for type 2 diabetes management. It works by mimicking a natural hormone in the body that helps regulate blood sugar and appetite.

  1. Bad Side Effects:
    • Gastrointestinal Issues: The most common side effects include nausea, vomiting, diarrhea, and constipation. These can be severe for some people, especially when starting the medication.
    • Risk of Pancreatitis: There is a rare but serious risk of pancreatitis (inflammation of the pancreas). Symptoms include severe abdominal pain, vomiting, and fever.
    • Thyroid Tumors: Animal studies have shown that semaglutide could increase the risk of thyroid tumors, including a type called medullary thyroid carcinoma, though this risk has not been conclusively proven in humans
    • Kidney Problems: Some people may experience kidney problems, particularly those who already have kidney issues
    • Hypoglycemia: When combined with other diabetes medications, especially insulin, the risk of low blood sugar (hypoglycemia) may increase
    • Dehydration and Electrolyte Imbalance: Due to the gastrointestinal side effects (nausea, vomiting, diarrhea), dehydration and an imbalance of electrolytes (like potassium) can occur.
Mounjaro (Tirzepatide)

Mounjaro is a newer medication used for weight loss and type 2 diabetes management. It works by stimulating two hormones, GLP-1 and GIP, which regulate blood sugar levels and hunger

  1. Orlistat
    • Bad Side Effects:
      1. Gastrointestinal Issues: Similar to Ozempic, the most common side effects include nausea, vomiting, diarrhea, constipation, and stomach pain. These side effects tend to be more common when starting the medication
      2. Risk of Pancreatitis: As with Ozempic, there is a potential risk of pancreatitis, though rare.
      3. Thyroid Cancer: Animal studies have shown that tirzepatide might increase the risk of thyroid tumors, although this hasn't been conclusively confirmed in humans
      4. Kidney Issues: Kidney problems may develop in some people, particularly those with pre-existing kidney conditions
      5. Hypoglycemia: There is a risk of low blood sugar, especially when combined with other diabetes medications like insulin or sulfonylureas.
      6. Increased Heart Rate: Some people may experience an increase in heart rate, which should be monitored closely.
Saxenda (Liraglutide)

Saxenda is another medication used for weight loss. It is a GLP-1 receptor agonist that works by reducing appetite, making it easier for people to stick to a calorie-controlled diet.

  1. Bad Side Effects:
    • Gastrointestinal Disturbances: The most common side effects include nausea, vomiting, diarrhea, constipation, and abdominal pain. These issues may reduce over time but can be bothersome in the short term.
    • Thyroid Tumors: Like other GLP-1 medications, there is a potential risk of thyroid tumors, including medullary thyroid carcinoma, though this is based on animal studies.
    • Pancreatitis: Although rare, Saxenda can increase the risk of pancreatitis. Seek immediate medical attention if you experience severe abdominal pain.
    • Kidney Problems: Some individuals may develop kidney issues, especially if they become dehydrated due to gastrointestinal side effects.
    • Hypoglycemia: In combination with other medications used for diabetes, Saxenda may increase the risk of low blood sugar
Bariatric Surgery

Bariatric surgery includes several procedures such as gastric bypass, sleeve gastrectomy, and adjustable gastric banding. These surgeries help with weight loss by restricting food intake or altering nutrient absorption

  1. Bad Side Effects:
    • Surgical Risks: As with any major surgery, bariatric procedures carry risks of complications such as infection, bleeding, blood clots, or reactions to anesthesia.
    • Nutritional Deficiencies: After surgery, patients must follow strict dietary guidelines and take supplements for life. Without these, patients may suffer from deficiencies in vitamins and minerals such as vitamin B12, iron, calcium, and vitamin D, leading to anemia, osteoporosis, or neurological problems
    • Dumping Syndrome (in gastric bypass): This occurs when food moves too quickly from the stomach into the intestines. It can cause nausea, vomiting, diarrhea, dizziness, and rapid heart rate.
    • Gallstones: Rapid weight loss after surgery can increase the risk of gallstones. Some patients may need additional treatments to remove the gallstones.
    • Weight Regain: Some individuals may regain weight after bariatric surgery if they do not adhere to lifestyle changes such as diet and exercise. The surgery may also lose some of its effectiveness over time.
    • Psychological Effects: Emotional adjustments after surgery can be difficult. Some patients may experience depression, anxiety, or body image issues following dramatic weight loss
Conclusion: Understanding the Risks

While weight loss therapies like Ozempic, Mounjaro, Saxenda, and Bariatric Surgery can be highly effective, they are not without their risks. It's crucial to weigh the potential benefits and side effects carefully with your healthcare provider. For any medication or surgery, always follow the recommended guidelines and report any side effects to your doctor.
If you're considering weight loss therapy, it's important to discuss:

  1. Your medical history
  2. Any existing health conditions
  3. The type of treatment that would best suit your lifestyle and goals

By staying informed and working closely with your healthcare team, you can make an educated decision about the best approach for achieving your weight loss goals.



Join Heart Club: If interested in personalized specialist care and access to a cardiologist at all times
//