Many people don’t realize that coffee and several other foods may partially block absorption of the thyroid medicine Synthroid (Benvenga et al, Thyroid, March 2008). Over-the-counter medicines such as calcium carbonate (Tums, for example) can also interfere with levothyroxine absorption (Singh, Weisler & Hershman, Thyroid, Oct. 2001). This doesn’t seem to be due to reduced acid in the stomach, though: famotidine (Pepcid) and esomeprazole (Nexium) both are more powerful acid suppressors than calcium carbonate, and neither one alters levothyroxine absorption (Ananthakrishnan et al, Thyroid, May 2008).
Taking Thyroid Medicine With Coffee Every Day:
Q. You wrote recently that coffee can interfere with levothyroxine absorption. I drink two cups of coffee with milk every morning right after taking my levothyroxine pill. My doctor says that is fine because I do it every morning. As a result, my thyroid levels stay very consistent. Taking it at nighttime makes it more difficult for me to stay on a regular schedule.
A. Thank you for sharing your experience. So long as you are consistent, your doctor can adjust your dose appropriately, and it sounds like that is happening.
Does All Thyroid Medicine React to Coffee?
Q. I’ve been on levothyroxine for years to treat hypothyroidism. I did not know that “take on an empty stomach” meant no coffee as well as no solid food.
When I learned that, I also read that with Tirosint you could have caffeine and even solid food. I persuaded my doctor to switch me to Tirosint. Now I don’t have to wait an hour after taking my thyroid medicine before having breakfast.
Tirosint in the Morning:
A. Tirosint capsules were developed to be better absorbed than levothyroxine tablets such as Synthroid. This medicine can be taken with breakfast and there is no effect on absorption (Cappelli et al, European Journal of Endocrinology, Jan. 2014). In general, this soft-gel form of thyroid medicine and a liquid form are better absorbed and less likely to interact with food than the usual levothyroxine pills (Fallahi et al, Expert Opinion on Drug Delivery, May 2017).
You pay for this convenience, of course: Tirosint costs more than Synthroid and about ten times as much as generic levothyroxine.
A Reader Wonders About Coffee and Levothyroxine:
Q. I was alarmed to hear about the interaction of coffee and levothyroxine. My doctor instructed me to take this medication daily “upon rising,” so that is what I do.
Usually I have a cup of coffee after 30 or 45 minutes. Does this mean I have been undoing the benefits of my medicine all this time? The only warnings I was given are to: take levothyroxine on an empty stomach and not to take it with magnesium or aluminum.
I drink three or four cups of coffee a day. My doctor checks my blood every six months and tells me to continue the medication at the same dosage because there has been no change in the level.
A. The Italian researchers who uncovered this interaction found that after an hour there was no problem, but when coffee is drunk right around the same time that levothyroxine is taken, it can reduce the absorption of this thyroid hormone.
Consistency Is Key:
The most important point when it comes to taking thyroid medication is to be consistent, however, and you are doing that admirably. That is why your doctor has not found variations in your blood level of TSH (thyroid stimulating hormone), the indicator used to assess thyroid function. Our advice: keep doing what you are doing.
Certain other foods could interfere with levothyroxine absorption, however. In addition to antacids containing magnesium or aluminum, people should avoid eating bran at the same time they take this thyroid medicine. Bran muffins or bran cereal could block absorption even more than coffee.
Watch Out for Minerals and Supplements:
Taking minerals such as calcium, iron or zinc around the same time as levothyroxine can also interfere with proper absorption of the hormone (Thyroid, May, 2011). Chromium picolinate also reduces levothyroxine absorption (Thyroid, Aug., 2007). One way to avoid such conflicts would be to take levothyroxine at bedtime (Archives of Internal Medicine, Dec. 13, 2010).
You will find greater detail about when and how levothyroxine tablets should be taken for greatest efficacy in our Guide to Thyroid Hormones.
You’ll find more information in our interviews with Dr. Antonio Bianco, one of the country’s leading biomedical researchers on thyroid disorders and thyroid patient advocate Mary Shomon. It is Show 1096: What You Need to Know about Treating Thyroid Disease.