Originally published August 29, 2008. Updated November 17, 2014.
I used to recommend Armour thyroid to treat an underactive thyroid. This product contains both T3 and T4, a combination of two hormones produced by the gland. I find that some patients respond better to the combination than to T4 (thyroxine) alone. (The drug most often prescribed for this purpose is Synthroid (also known as levothyroxine), a synthetic form of T4.
Thyroid deficiency (hypothyroidism) can cause a number of unpleasant symptoms including low energy levels, constipation, dry, flaky skin, a sensitivity to cold, depression, weight gain, joint stiffness and hair loss. The only effective way to treat hypothyroidism is to replace the deficient hormones.
The reason I no longer recommend Armour thyroid is because it is animal derived (from pigs), which makes me a little nervous, because of the risk, however slight, of disease transmitted by animal tissue. Instead, I recommend Thyrolar, a synthetic drug that gives you both T3 and T4, and most closely approximates the natural mixture of hormones that the thyroid produces. You may find that the combination has a better effect on mood than thyroxine alone.
Since most cases of underactive thyroid are due to Hashimoto's thyroiditis, an autoimmune disorder that causes inflammation of the thyroid gland, I also suggest following my anti-inflammatory diet. In addition, be sure to exercise regularly and practice relaxation techniques.
I also advise against excessive intake of certain foods (called goitrogens) that can interfere with thyroid hormone production. These include cabbage, broccoli, cauliflower, radishes, rutabagas, turnips, peanuts and soybeans. You don't have to avoid these foods but don't overdo them.
It's best to take thyroid medication on an empty stomach because some foods (particularly those high in fiber) can interfere with absorption. Certain drugs and supplements can interact with thyroid medication as well, especially if you take them at the same time of day. These include aspirin, calcium, Coumadin and other blood thinners, estrogen, iron, psyllium and other fiber supplements, and certain antacids. You shouldn't have any problem if you take your thyroid medication two hours before or after taking any of these drugs or supplements.
You can also try performing a shoulder stand, which can help by increasing circulation to the thyroid (this isn't a good idea if you're pregnant, menstruating or have glaucoma and should be done with caution if you have high blood pressure or sinus problems). And be sure to have your thyroid function checked periodically to see whether the dosage of medication needs to be adjusted. Anyone who is or ever has been on thyroid replacement or have had a history of thyroid dysfunction should sure to tell any doctor you consult, no matter what your present symptoms.
Andrew Weil, M.D.