GLP-1 medications are remarkably effective, but they're not appropriate for everyone. Some conditions are absolute contraindications. Others require careful consideration and monitoring.
Absolute Contraindications
Do NOT take GLP-1 medications if you have:
Personal or Family History of Medullary Thyroid Cancer (MTC)
GLP-1 medications caused thyroid C-cell tumors in rodents. While not proven in humans, anyone with MTC or a family history should not take these drugs.
Multiple Endocrine Neoplasia Syndrome Type 2 (MEN 2)
This genetic syndrome increases thyroid cancer risk. GLP-1 medications are contraindicated.
Pregnancy
Animal studies show fetal harm. Stop at least 2 months before trying to conceive. If you become pregnant while taking, stop immediately.
Known Hypersensitivity
If you've had a serious allergic reaction to semaglutide, tirzepatide, or any component, do not take again.
Use With Caution
These conditions require careful consideration and monitoring:
⚠️ History of Pancreatitis
GLP-1s may increase pancreatitis risk. If you've had pancreatitis, discuss carefully with your doctor. Stop immediately if you develop severe abdominal pain.
⚠️ Diabetic Retinopathy
Rapid blood sugar improvement can temporarily worsen diabetic eye disease. Get baseline eye exam; monitor closely.
⚠️ History of Eating Disorders
Appetite-suppressing medications can be triggering. Requires careful psychological support and monitoring.
⚠️ Severe GI Disease
Gastroparesis, inflammatory bowel disease, or severe GERD may be worsened by slowed gut motility.
⚠️ Kidney Disease
Dehydration from GI side effects can worsen kidney function. Close monitoring and hydration are essential.
May Not Be Appropriate
Situations Where GLP-1s May Not Be the Right Choice
- BMI under threshold: FDA approval is for BMI ≥30 or BMI ≥27 with comorbidity. Lower BMI = different risk/benefit calculation.
- Underweight or malnutrition: Further appetite suppression is dangerous.
- Planning surgery soon: Need to stop 1-4 weeks before anesthesia.
- Breastfeeding: Unknown if passes into breast milk; not recommended.
- Type 1 diabetes: Not approved for T1D; different mechanism.
- Children under 12: Limited safety data in pediatric populations.
The Bottom Line
Absolute contraindications: personal/family history of medullary thyroid cancer, MEN 2 syndrome, pregnancy, and known hypersensitivity. Use caution with: history of pancreatitis, diabetic retinopathy, eating disorders, severe GI disease, and kidney disease. May not be appropriate for: those below BMI thresholds, underweight individuals, those planning surgery, breastfeeding mothers, type 1 diabetics, and young children. Always disclose your full medical history to your prescriber.
Sources
- FDA prescribing information for semaglutide and tirzepatide.
- Endocrine Society clinical guidelines.
- American Diabetes Association standards of care.