Taking Thyroid Medicine Properly

Millions of people suffer from an underactive thyroid gland. That is why the synthetic thyroid hormone levothyroxine (Synthroid, Levothroid, Levoxyl, Unithroid, etc.) is one of the most widely prescribed medications in the pharmacy. This can be a relatively simple fix for a difficult problem, but only if you are taking thyroid medicine properly. Many readers would like to know how to do that.

Taking Thyroid Medicine at Daybreak

Q. I have taken Synthroid for decades to treat hypothyroidism. Occasionally my TSH has been elevated, with depressed free T4 or free T3.

So now I set my alarm for 6:30 am, take my Synthroid, then snooze a little more before starting my day. I have two pug dogs, so I’ve devised a morning routine to take care of their needs first before I drink my coffee. I take my vitamins and calcium with lunch.

When I started a vegan diet, my lab values quickly went off the rails. I traced the cause to my diet: lots of tofu, products containing soy isolate, high fiber and, of all things, my evening snack of walnuts or pecans! I’m now back on a Mediterranean diet. My doctor has added a low dose of T3 (liothyronine) to my Synthroid. Getting used to the T3 took persistence, but I certainly feel better.

Problems with Coffee

A. Your story brings out a lot of potential pitfalls in taking thyroid medicine. Scientists have found that taking Synthroid around the same time as coffee, high-fiber foods or grapefruit juice can interfere with its absorption (Medicina, 2025).  They recommend allowing three to four hours between consuming any of these and taking the pill. That was presumably what your morning ritual was designed to accomplish.

How About Tea?

Others have found that tea also interferes with absorption (Frontiers in Endocrinology, Sep. 12, 2022).  Some people may find it more convenient to take their thyroid hormone in the evening so long as they don’t eat before bedtime.

An interaction with soy was detected years ago, but there has not been much follow-up research (Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences, Sep. 25, 2002). Experts have, in some cases, downplayed the potential for harm (Nutrients, Aug. 2010).

Why Add T3 to the Mix?

Taking liothyronine in addition to levothyroxine is not standard practice, but some patients report they feel better taking both hormones (Journal of Clinical Endocrinology and Metabolism, Oct. 21, 2021). You can read more at this link.

Be Alert for Interactions with Minerals

Q. My thyroid gland doesn’t work very well, so I have been taking levothyroxine. My new doctor has suggested a multivitamin and a calcium supplement. Can I take all these pills at once? I know some things don’t agree with the thyroid hormone.

A. You’ve been paying attention. Calcium can interfere with the absorption of levothyroxine (Pharmaceuticals, March 2, 2021).  If your multivitamin contains iron, that might also pose a problem.

It isn’t hard to get around this difficulty, though. Simply take your nutritional supplements at a different time. When you check the label on your multivitamin, also look to see if it contains biotin. That B vitamin can interfere with accurate thyroid test results, so you may want to discontinue the multi for a couple of days before your regular blood work.

Avoiding Interactions with Levothyroxine

Q. I’ve been taking levothyroxine for more than a dozen years. I just recently learned I’ve been taking it at the wrong time–along with breakfast and coffee, not to mention vitamins, minerals, probiotics, Citrucel and other medications. Can you clear up my confusion about how to take it properly?

A. Taking your thyroid medicine with coffee, mineral supplements (especially iron or calcium) or fiber such as bran cereal or Citrucel can interfere with its absorption (Thyroid, March 2008).  Using a calcium-fortified fruit juice to take the medication could severely limit how much gets into your bloodstream. So could a high-calcium food like Greek yogurt. Other foods that may cut absorption of levothyroxine include grapes, soybeans and papaya (European Review for Medical and Pharmacological Sciences, 2014).

Watch Out for Drugs

Drug interactions can be troublesome. There are several medications, especially those intended to moderate stomach acid, that can also interfere with proper absorption (Journal of Pharmacy & Pharmaceutical Sciences, 2015). Proton pump inhibitors (esomeprazole, omeprazole, etc.) at high doses may affect absorption. So do antacids taken at the same time as the thyroid pill.

One supplement that you might want to include with your thyroid is vitamin C. In one randomized controlled study, swallowing the pill with water containing 500 mg ascorbic acid dissolved in it improved absorption as determined by lower TSH and higher levels of T4 and T3 (Journal of Clinical Endocrinology and Metabolism, June, 2014).

Taking Thyroid Medicine at Bedtime

Why not take your levothyroxine at bedtime? A small study showed that the drug is absorbed better in the evening (Clinical Endocrinology, Jan., 2007). As long as you don’t eat within two or three hours of retiring, your thyroid medication should work fine and nothing else will interfere with it.

An alternative to that would be Tirosint. This liquid formulation is designed to be absorbed much better, without interference from breakfast beverages such as coffee or a latte (Pharmaceutics, Dec., 2013).

Learn More:

You can learn more about how diet, including high-fiber foods and soy, affects thyroid treatment in our eGuide to Thyroid Hormones. You will also learn how to interpret lab values as well as the pros and cons of adding T3 to the regimen. For more discussion of the nuances of treatment of hypothyroidism, you may wish to listen to our interview with Dr. Antonio Bianco. It is Show 1330: Rethinking Hypothyroidism.