The Problem With Coffee and Thyroid Medication

When it interferes with levothyroxine absorption

Daniel Kim Photography/Stocksy United

Around the world, many people start their day with a cup of coffee, a cappuccino, or an espresso. At the same time, there are many people with various thyroid conditions who rely on synthetic thyroid hormone replacement medication like levothyroxine (i.e., Synthroid, Levoxyl, and Unithroid) to treat their hypothyroidism. And following doctor's instructions, most of those people take their thyroid pills in the morning.

There is a problem, however, when coffee drinkers take their prescription thyroid medication along with their morning coffee or espresso. Several studies have found that having coffee or espresso at the same time—or shortly after—taking levothyroxine tablets can significantly lower the absorption of the thyroid medication.

In one study published in the journal Thyroid, researchers found the rise of T4—a reflection of absorption of the medication—reduced by 25 percent, and they even noticed drops by as much as 57 percent in other patients in the study. Overall, the Thyroid journal study showed that the reduction typically ranged from 23 percent to as much as 55 percent.

Consistently, researchers have found that for patients taking levothyroxine tablets, absorption is affected by drinking coffee and espresso within an hour of taking the thyroid drugs. The ability to reach targeted thyroid levels is impaired if a thyroid patient does not wait 60 minutes after taking the levothyroxine before drinking coffee or espresso.

Coffee-Resistant Levothyroxine?

Some studies have shown that the levothyroxine medication known as Tirosint, which is a liquid form of levothyroxine in a gel capsule, can bypass the effects of coffee. Tirosint—a form of levothyroxine developed primarily for people with digestive, absorption, or allergy issues appears to allow patients to take their levothyroxine at the same time as coffee, with no negative impact on absorption.

What the Study Did Not Evaluate

It's important to note that there are a number of things the study did not evaluate:

  • The study did not differentiate between regular and decaffeinated coffee.
  • The study did not test the effect of coffee on thyroid hormone replacement medications beyond levothyroxine form. So, we do not have any scientific conclusions regarding synthetic T3 (i.e., Cytomel) and natural desiccated thyroid drugs like Nature-Throid and Armour Thyroid. The study also did not include antithyroid drugs (like methimazole or PTU), which are used to treat hyperthyroidism.
  • The study did not evaluate the effects of caffeinated or herbal teas.

So, we don't know if these same negative effects would be seen with drinking tea or other beverages within an hour of taking levothyroxine.

At this point, we also do not have any conclusions regarding whether the cautions regarding coffee and espresso also apply to other thyroid hormone replacement drugs besides levothyroxine, or to antithyroid drugs.

Implications for Thyroid Patients

The recommendations by researchers are clear: You should wait at least 60 minutes after taking your levothyroxine before you drink coffee or espresso.

And if that is not possible, then patients may want to talk to the doctor about taking levothyroxine medication at night. Some studies have shown that taking levothyroxine at bedtime may improve absorption. It also allows for a thyroid patient to have a morning cup of coffee without concern for interference with thyroid medication.

If you have to have your coffee and your levothyroxine in the morning and can't wait, then you may want to ask your doctor about Tirosint as a substitute.

It's important to note, however, that any time you are finding it difficult to regulate your thyroid function while taking any thyroid hormone replacement drug, experts recommend that you take your medication consistently, ideally in the morning, at least an hour before any food or drink besides water and at least three or more hours apart from any supplements, juices, or foods that contain iron, calcium, or fiber.


Benvenga S, et al. Altered Intestinal Absorption of L-Thyroxine Caused by Coffee. Thyroid. 2008; 18(3):293-301.

Mazzaferri E. Thyroid Hormone Therapy. Clinical Thyroidology for Patients: Summaries for Patients from Clinical Thyroidology. 2008; Vol 1, Iss 1.

Sindoni A, et al. Case Report: Coffee Impairs intestinal Absorption of Levothyroxine: Report of Additional Cases. Hot Thyroidology. Article 5/09.

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