Can Glucagon-like peptide-1 (GLP-1) analogs, such as exenatide (Byetta) or liraglutide (Victoza), cause hair loss?

GLP-1 Receptor Agonists and Hair Loss

Based on current evidence, GLP-1 receptor agonists (GLP-1 RAs) are not directly associated with hair loss as a common or documented side effect. The most comprehensive guidelines and clinical evidence do not list alopecia among the known adverse effects of this medication class.

Known Side Effects of GLP-1 RAs

GLP-1 receptor agonists have well-documented side effect profiles that include:

• Gastrointestinal effects: The most common adverse effects are nausea, vomiting, and diarrhea 1

  • These side effects are typically transient and dose-dependent
  • Less common with long-acting formulations than short-acting ones
  • Can be mitigated by gradual dose escalation

• Other documented adverse effects:

  • Risk of hypoglycemia (minimal when used alone, increased when combined with insulin or sulfonylureas) 1
  • Increased heart rate 1
  • Potential risk of gallbladder disease, including acute cholecystitis 1
  • Rare cases of acute pancreatitis 1, 2
  • Delayed gastric emptying 1
  • Increased risk of pulmonary aspiration under anesthesia 2

Weight Loss and Potential Indirect Effects

GLP-1 RAs are known to cause significant weight loss:

• Liraglutide: 2-4% of total body weight 1
• Semaglutide: up to 10% of total body weight 1

While rapid weight loss from any cause can sometimes trigger temporary hair shedding (telogen effluvium), this is:

1. Not specific to GLP-1 RAs
2. Generally temporary
3. Not directly mentioned in any of the major guidelines for GLP-1 RAs

Clinical Implications

If a patient on a GLP-1 RA experiences hair loss:

1. Consider alternative causes:

   • Nutritional deficiencies (particularly important during weight loss)
   • Thyroid dysfunction
   • Hormonal changes
   • Stress
   • Other medications

2. Evaluate for nutritional status:

   • Rapid weight loss can sometimes lead to deficiencies in micronutrients important for hair growth
   • Consider checking levels of iron, zinc, vitamin D, and B vitamins 3

3. Management options:

   • If hair loss appears related to rapid weight loss, slowing the rate of weight loss by adjusting the GLP-1 RA dose might help
   • Ensure adequate protein intake during weight loss
   • Consider appropriate supplementation if deficiencies are identified

Conclusion

The major guidelines from the American Diabetes Association, European Association for the Study of Diabetes, and American College of Cardiology do not list hair loss as a recognized side effect of GLP-1 receptor agonists 1. While rapid weight loss from any cause can potentially trigger temporary hair shedding, this is not a direct effect of the medication class itself and would typically resolve with time or stabilization of weight.

If hair loss occurs in a patient taking a GLP-1 RA, a thorough evaluation for other causes should be conducted before attributing it to the medication.