How Coffee Interferes With Thyroid Medication

Many people like to drink a cup of coffee before heading to work or getting the day started. But if you do so before or within an hour after taking certain thyroid medications, it can make the drugs less effective.

The drug levothyroxine, known by the names Synthroid, Levoxyl, Unithyroid, and others, is a thyroid drug that can be affected by coffee. When taken with coffee, the drug may not be properly absorbed, which lowers the amount of levothyroxine that enters the bloodstream.

This article looks at how caffeine affects levothyroxine in its different forms and whether switching to a different thyroid drug is an option.

Effects of drinking coffee in close succession to thyroid medication.

Verywell / Melissa Ling

Caffeine and Levothyroxine

Levothyroxine is used in people with hypothyroidism whose thyroid glands are not producing enough of a hormone called T4 to keep the body functioning normally. Levothyroxine is a synthetic compound identical to T4 that is used when the thyroid gland isn't working correctly or has been removed.

Doctors generally recommend that you take your thyroid drugs in the morning on an empty stomach and that you wait an hour before eating. Eating before levothyroxine has time to be fully absorbed in the intestines can lower the amount of the drug that enters the bloodstream.

Coffee and other caffeinated beverages affect the absorption of the drug in a different way. Studies have found that drinking coffee with levothyroxine decreases absorption by increasing the speed at which the drug passes through the intestines.

Caffeine is a stimulant that can increase intestinal motility, the muscle contractions that move food through the digestive tract. Caffeine also has a mild laxative effect and increases the amount of fluid in stools.

Both of these things can cause levothyroxine to move through the intestines too quickly, before it has the chance to be absorbed. When this happens, your thyroid hormone levels can drop and lead to symptoms of hypothyroidism, including fatigue, muscle weakness, weight gain, hoarseness, and sensitivity to cold.

Levothyroxine absorption may also be decreased when taken with black teas, hot cocoa, or caffeinated soft drinks.

Other types of thyroid drugs, including triiodothyronine (T3) and antithyroid drugs, are not affected by caffeine.


Caffeine in coffee, tea, and other caffeinated beverages decreases the absorption of levothyroxine by causing the drug to move too quickly through the intestines before it has the chance to be absorbed.

Forms Not Affected by Caffeine

Certain non-tablet formulations of levothyroxine are designed to be absorbed quickly in the digestive tract and are not affected by caffeine in the same way as tablets.

Tirosint is a soft gel form of levothyroxine, and Tirosint-Sol is the liquid form. These medications are absorbed more rapidly than the standard formulations. The gel and liquid forms were developed for people who have digestive disorders such as celiac disease that prevent the proper absorption of nutrients.

Studies have also shown that Tirosint or Tirosint-Sol can be taken at the same time as coffee without any problems with absorption or effects on T4 hormone levels.


Tirosint and Tirosint-Sol are soft gel and liquid formulations of levothyroxine that are not affected by caffeine.

Switching Medication

Switching from your current levothyroxine formulation to another is not generally recommended because it can cause your thyroid levels to fluctuate.

However, if you are having problems with absorption due to conditions like chronic diarrhea or celiac disease and experiencing fluctuations in your T4 levels, switching to another form may be a solution. Speak with your healthcare provider to see if Tirosint or Tirosint-Sol may be a reasonable option for you.

If you do switch, be sure to take your medications as prescribed and follow up with routine blood tests to ensure that the dose is correct and your T4 levels are normal.


Caffeine in coffee and other caffeinated beverages can affect the absorption of the thyroid drug levothyroxine by making the drug pass through your gut too quickly. This can cause your T4 hormone levels to drop or fluctuate.

To avoid this, levothyroxine should be taken on an empty stomach and you should wait an hour before eating anything or drinking a caffeinated beverage.

If you have trouble controlling your thyroid hormones and your doctor believes that intestinal absorption is to blame, you may be switched to the soft gel or liquid formation of levothyroxine called Tirosint and Tirosint-Sol.

A Word From Verywell

A thyroid drug works best if you take it correctly and consistently. This means taking it every day, ideally at the same time in the morning on an empty stomach. Taking your drugs at different times or with food can cause your hormones levels to fluctuate.

You should also not take levothyroxine within four hours of a calcium supplement or two to four hours of an iron supplement as these can also affect absorption. Separating the doses can ensure you get the best results from your thyroid drugs.

Frequently Asked Questions

  • What foods and supplements can interfere with thyroid medication?

    Besides coffee, some other foods, supplements, and medications can affect how well levothyroxine works. These include:

    • Foods containing soy and cottonseed meal
    • Walnuts
    • Dietary fiber
    • Grapefruit juice
    • Iron supplements
    • Calcium supplements
    • Antacids

  • Can you take levothyroxine in the evening?

    It may be OK to do so but talk with your doctor first. The usual recommendation is to take it on an empty stomach in the morning. However, you can take it in the evening at least three to four hours after you've eaten.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Mary Shomon
Mary Shomon is a writer and hormonal health and thyroid advocate. She is the author of "The Thyroid Diet Revolution."