Yes, but keep them at least 4 hours apart.
Levothyroxine is easy to block: calcium, iron, antacids, and magnesium supplements bind it in the stomach so less of your dose gets absorbed. MedlinePlus says to take calcium carbonate (Tums) or iron at least 4 hours before or after levothyroxine, and the NHS lists antacids, indigestion treatments, calcium, and iron as interfering products. Magnesium is not named on the levothyroxine label, but it acts the same way, which is why pharmacists apply the same 4-hour rule. Watch out for hidden magnesium too: many multivitamins, sleep powders, and antacids contain it. A clean routine is levothyroxine with water on an empty stomach in the morning, magnesium with a later meal.
Can I take magnesium with levothyroxine? What to do
Common questions
Can I take magnesium with levothyroxine?
Yes, you can take magnesium if you take levothyroxine, but not at the same time of day. Minerals like calcium and iron are proven to bind levothyroxine in the gut and stop it being absorbed, and magnesium supplements and antacids behave the same way. MedlinePlus advises taking calcium carbonate or iron at least 4 hours before or after levothyroxine, and the NHS lists antacids, indigestion remedies, calcium, and iron as products that interfere with it. The practical rule most pharmacists give: keep a 4-hour gap between levothyroxine and any magnesium supplement, multivitamin containing magnesium, or antacid. The simplest routine is levothyroxine first thing in the morning with water, then magnesium at lunch or dinner. You do not need to stop magnesium. If your thyroid levels suddenly look off after starting a supplement, tell your doctor, because your levothyroxine dose may need adjusting.