MODERATE — Monitor Closely
FDA-documented absorption interaction. Separate administration by at least 4 hours. Take levothyroxine on empty stomach, ideally 30-60 minutes before any food or supplements.
Evidence level: STRONG
Calcium supplements (like Tums or calcium carbonate) can significantly reduce how much thyroid medication (levothyroxine) your body absorbs. This can make your thyroid medication less effective.
Calcium carbonate adsorbs levothyroxine in the GI tract, reducing its absorption by up to 25%. FDA levothyroxine label warns about calcium supplements and antacids.
Take your thyroid medication first thing in the morning on an empty stomach with water. Wait at least 4 hours before taking calcium supplements. Consistency in timing is key for stable thyroid levels.
Take Levothyroxine on an empty stomach, 30-60 minutes before food or other medications. Space Calcium Carbonate at least 1-2 hours from your thyroid dose. Thyroid medications are highly sensitive to timing — consistency is critical for stable blood levels.
Higher risk for: elderly with cardiac conditions, those with adrenal insufficiency, recent thyroid dose adjustments, concurrent calcium/iron/antacid use (absorption interference), or narrow therapeutic index sensitivity.
Fatigue, weight gain, cold intolerance, constipation, dry skin, hair loss — signs that thyroid medication is not working well enough
Discuss 4-hour separation rule. Take levothyroxine on empty stomach 30-60 min before breakfast. Get TSH checked if calcium supplement was recently started or timing changed.
Thyroid medications are sensitive to absorption interference. Take levothyroxine on an empty stomach, 30-60 minutes before food or other supplements. Space calcium, iron, and antacids at least 4 hours away. Selenium and zinc are generally safe thyroid-supporting nutrients.
Calcium supplements (like Tums or calcium carbonate) can significantly reduce how much thyroid medication (levothyroxine) your body absorbs. This can make your thyroid medication less effective.
Take Levothyroxine on an empty stomach, 30-60 minutes before food or other medications. Space Calcium Carbonate at least 1-2 hours from your thyroid dose. Thyroid medications are highly sensitive to timing — consistency is critical for stable blood levels.
Fatigue, weight gain, cold intolerance, constipation, dry skin, hair loss — signs that thyroid medication is not working well enough
Thyroid medications are sensitive to absorption interference. Take levothyroxine on an empty stomach, 30-60 minutes before food or other supplements. Space calcium, iron, and antacids at least 4 hours away. Selenium and zinc are generally safe thyroid-supporting nutrients.
Discuss 4-hour separation rule. Take levothyroxine on empty stomach 30-60 min before breakfast. Get TSH checked if calcium supplement was recently started or timing changed.
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