Thyroid medication provides the thyroid hormone you need when your thyroid malfunctions. When your thyroid fails to produce enough hormone, you suffer from hypothyroidism, which can cause weight gain, a rise in cholesterol, hair loss and other symptoms. Taking thyroid medication daily resolves this problem, but for the medication to work properly, you shouldn't take it at the same time you take calcium supplements.
Calcium Supplement Interaction
Calcium supplements, particularly calcium carbonate, interfere with your body's ability to absorb thyroid hormone. In 2001, researchers with the Veterans Affairs Greater Los Angeles Health Care System measured thyroid hormone levels in seven study volunteers when levothyroxine, a common thyroid medication, was given both alone and with 2 g of calcium carbonate. When the subjects took levothyroxine by itself, they had absorbed 83.7 percent of the hormone after two hours, but taking the medication with calcium carbonate reduced absorption levels to 57.9 percent.
Consequences
Thyroid medication comes in a variety of strengths. The right strength for you depends on a variety of factors, including how much hormone your thyroid makes. The proper dosage ensures that your body functions properly and you feel your best. Getting the dosage wrong limits the effectiveness of the medication. Your doctor will conduct regular blood tests to check your medication's effectiveness. If you're at the proper dose but calcium supplements inhibit the medication's absorption rate, you're not getting enough of the medication into your body to do its job.
Other Forms of Calcium Carbonate
Calcium carbonate is also a common ingredient in many forms of antacid, so doctors advise patients who are taking thyroid medication to avoid taking antacids within several hours of taking thyroid medication. No standard has been set for how long you should wait between taking thyroid medication and any form of calcium carbonate. Most doctors advise you take these medications as far apart as possible. For instance, take your thyroid medication in the morning and calcium in the evening.
Thyroid Medication
Thyroid medications are sold under a variety of brand names and formulations. These include Armour thyroid, or natural thyroid; levothyroxine, sold as Levoid, Levothroid, Levoxine, Levoxyl or Synthroid; dextrothyroxine, or Choloxin; thyroglobulin, also known as proloid; liotrix, brand name Euthroid or Thyrolar; and liothyronine, sold as Cytomel or Triostat. If you're taking any of these medications and a calcium supplement, ask your doctor when you should take the two medications.
References
- Washington State University; Calcium to Treat and Prevent Osteoporosis; September 2010
- New York University Langone Medical Center; Thyroid Hormone; February 2011
- "Thyroid"; The Acute Effect of Calcium Carbonate on the Intestinal Absorption of Levothyroxine; N. Singh, S.L. Weisler and J.M. Hershman; October 2001
