How does GLP-1 (Glucagon-Like Peptide-1) receptor agonist therapy, such as liraglutide (Victoza) or semaglutide (Ozempic), affect iron absorption in patients?

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Last updated: June 3, 2025View editorial policy

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From the Guidelines

GLP-1 receptor agonists may compromise iron absorption, including oral supplementation, due to their effects on gastric emptying and gastrointestinal side effects, and thus patients on these medications should be monitored for signs of iron deficiency anemia. The use of GLP-1 receptor agonists, such as liraglutide and semaglutide, can cause delayed gastric emptying, as shown in a study by Umapathysivam et al. 1, which may alter the transit time of food through the duodenum and upper jejunum where iron absorption primarily occurs. Additionally, these medications can cause gastrointestinal side effects such as nausea, vomiting, and reduced food intake, which may decrease iron consumption and absorption 1.

Key Considerations

  • Patients on GLP-1 receptor agonists, particularly those already at risk for iron deficiency, should be monitored for signs of iron deficiency anemia, including fatigue, weakness, and pale skin.
  • Regular blood tests to check iron levels, ferritin, and complete blood counts may be warranted in at-risk individuals 1.
  • The standard dosing of these medications should not be altered solely due to iron absorption concerns, but rather iron supplementation should be considered if deficiency develops.

Management Strategies

  • Patients on GLP-1 receptor agonists should be advised to consume iron-rich foods and consider iron supplementation if they are at risk of iron deficiency 1.
  • Healthcare providers should be aware of the potential for iron deficiency anemia in patients taking GLP-1 receptor agonists and monitor them accordingly.
  • Further research is needed to fully understand the effects of GLP-1 receptor agonists on iron absorption and to determine the best strategies for managing iron deficiency in patients taking these medications 1.

From the Research

GLP-1 Receptor Agonists and Iron Absorption

  • The available evidence does not directly address the impact of GLP-1 receptor agonists on iron absorption, including oral supplementation 2, 3, 4, 5, 6.
  • GLP-1 receptor agonists, such as liraglutide and semaglutide, are known to delay gastric emptying, which could potentially affect the absorption of nutrients, including iron 5.
  • However, there is no specific information available on how GLP-1 receptor agonists affect iron absorption in patients.
  • The primary mechanisms of action of GLP-1 receptor agonists include augmentation of hyperglycemia-induced insulin secretion, suppression of glucagon secretion, deceleration of gastric emptying, and reduction in calorie intake and body weight 2.
  • While GLP-1 receptor agonists have been shown to have various benefits, including improved glycemic control, weight loss, and reduced cardiovascular risk, their effects on iron absorption are not well understood 2, 3, 6.
  • Further research is needed to determine the potential impact of GLP-1 receptor agonists on iron absorption and to provide guidance on the use of oral iron supplements in patients taking these medications.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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