Supplement stacks / Iron + Levothyroxine
Can You Take Iron with Levothyroxine?
Iron supplements can interfere with the absorption of levothyroxine, potentially reducing its effectiveness. It is generally recommended to separate the intake of these two substances by at least 4 hours to minimize interaction risks. Both iron and levothyroxine have limited evidence quality regarding their interactions, and consulting a healthcare provider is advised for personalized guidance.
Conservative, AI-assisted reading of publicly available medical sources (NIH, Mayo Clinic, WebMD, Examine.com). Informational only — it can't account for your medications, conditions, or genetics.
Suggestion: Take iron and levothyroxine at least 4 hours apart.
Generally safe when taken as directed; excessive intake can lead to toxicity.
Typical dosage: 18-45 mg daily, depending on individual needs.
- Constipation
- Nausea
- Stomach upset
- Monitor for gastrointestinal side effects; consult healthcare provider if experiencing severe symptoms.
Safe when taken as prescribed; requires regular monitoring of thyroid levels.
Typical dosage: Typically 1.6 mcg/kg body weight daily, adjusted based on thyroid function tests.
- Increased heart rate
- Nervousness
- Weight loss
- Regularly monitor thyroid hormone levels; adjust dosage as needed.
Iron should be taken at a different time than levothyroxine to ensure optimal absorption of both.
- Consult with a healthcare provider before starting iron supplements.
- Consider timing of iron and levothyroxine to avoid absorption issues.
- Calcium, iron, and magnesium bind thyroid medication (levothyroxine) and block its absorption, which can leave your thyroid under-treated. Separate them by at least 4 hours: take levothyroxine on an empty stomach (ideally 30-60 minutes before breakfast) and take the mineral or multivitamin later in the day. Ask for a TSH recheck if you start or change the mineral.
- Take iron and levothyroxine at least 4 hours apart to avoid absorption interference.
Can you take Iron and Levothyroxine together?
Iron supplements can interfere with the absorption of levothyroxine, potentially reducing its effectiveness. It is generally recommended to separate the intake of these two substances by at least 4 hours to minimize interaction risks. Both iron and levothyroxine have limited evidence quality regarding their interactions, and consulting a healthcare provider is advised for personalized guidance.
How safe is the Iron and Levothyroxine combination?
Our analysis of publicly available medical sources scores this combination 6/10 (medium risk). This is an informational estimate, not medical advice — always confirm with a healthcare professional.
When should you take Iron and Levothyroxine?
Iron should be taken at a different time than levothyroxine to ensure optimal absorption of both.
What should you watch out for when combining Iron and Levothyroxine?
Calcium, iron, and magnesium bind thyroid medication (levothyroxine) and block its absorption, which can leave your thyroid under-treated. Separate them by at least 4 hours: take levothyroxine on an empty stomach (ideally 30-60 minutes before breakfast) and take the mineral or multivitamin later in the day. Ask for a TSH recheck if you start or change the mineral. Take iron and levothyroxine at least 4 hours apart to avoid absorption interference.
Taking more than these two? Run your complete supplement list — plus any medications — through the live checker for a combined analysis.
Analyze my stackGenetics change how you process supplements like these. Upload raw 23andMe or Ancestry data for a personalized supplement report.
See the DNA reportNot medical advice
Analysis generated August 10, 2026 · Sources include NIH, Mayo Clinic, WebMD, and Examine.com · How our analysis works