The Interaction: Magnesium can interfere with the absorption of thyroid medications such as levothyroxine. Since thyroid hormone levels require precise management, even small changes in absorption can affect treatment outcomes.
What to Do: Levothyroxine should usually be taken on an empty stomach, first thing in the morning. Magnesium should be taken several hours later—typically in the afternoon or evening—to ensure optimal absorption of both.
Medications to Watch: Levothyroxine (Synthroid, Levoxyl), liothyronine (Cytomel).
Diuretics (Water Pills)
The Interaction: Diuretics affect magnesium levels in complex ways. Some diuretics (like loop and thiazide diuretics) increase magnesium loss through urine, potentially leading to deficiency. Others (like potassium-sparing diuretics) may cause the body to retain magnesium, potentially leading to elevated levels.
What to Do: Regular medical checkups and blood tests can help determine whether magnesium supplementation is appropriate. Never supplement without medical guidance if you take diuretics long-term.
Medications to Watch: Furosemide (Lasix), hydrochlorothiazide, spironolactone, triamterene.
Practical Strategies for Safe Magnesium Supplementation
