Drinking Coffee with Synthroid Undermines a Morning Dose

How do you take your Synthroid, the levothyroxine medication used to treat an underactive thyroid gland? Usually, people are urged to take it first thing in the morning. Ideally, it is taken at least half an hour to an hour before eating or drinking anything else. That’s because quite a few things interfere with Synthroid absorption. But not everyone is willing to give up morning coffee with Synthroid. What else can you do? Some people have found that taking levothyroxine at bedtime is an option.

What Is the Problem of Coffee with Synthroid?

Q. I take levothyroxine for hypothyroidism and have done so for 20 years. Usually I take it with my morning coffee.

I started on 75 mcg, but the dose has gradually been increased over the years. It’s gone from 75 to 100, 150 and now 175 mcg. That dose seems high to me. Could I be having trouble absorbing this thyroid hormone?

A. Coffee can interfere with the absorption of levothyroxine such as Synthroid (Thyroid, March 2008).  Coffee is not the only thing that could cause trouble for thyroid absorption. So can tea (Frontiers of Endocrinology, Sep. 12, 2022).

Taking Levothyroxine at Breakfast:

Taking levothyroxine with a healthy high-fiber breakfast such as oatmeal or a bran muffin could also limit absorption. So could antacids, acid-suppressing drugs or mineral supplements such as iron, calcium or magnesium. Even a simple multivitamin could interfere with your thyroid medication. You can learn more about the best ways to take your thyroid medicine from our eGuide to Thyroid Hormones.

We agree that 175 mcg might be a high dose. Too much thyroid hormone can weaken bones and affect cardiovascular health. It might also lead to diarrhea, insomnia, anxiety or tremor. If you experience any of these symptoms, you may wish to discuss this with your healthcare provider.

Can You Improve Levothyroxine Absorption?

Q. I have been taking levothyroxine for a few years to treat an underactive thyroid. You have written about not drinking coffee while you take this pill because it reduces absorption. Is there anything I can take that will improve absorption?

A. Coffee and tea can both interfere with the absorption of levothyroxine pills, such as Synthroid. Experts generally recommend allowing at least an hour to pass after taking levothyroxine tablets before enjoying a cup of either beverage.

Research suggests that vitamin C might improve absorption. A study found that hypothyroid people had a higher rate of vitamin C insufficiency than healthy folks (Frontiers in Endocrinology, Oct. 23, 2025). The researchers then tested supplements of 1 gram of vitamin C daily for those on levothyroxine. They found a benefit, but they caution that their placebo-controlled study was too small to be definitive. As far as we can tell, there is no research to suggest that vitamin C could overcome the effects of coffee or tea on levothyroxine absorption.

Is It Essential to Take Synthroid in the Morning?

Q. I was told to take my Synthroid before breakfast. Some of my favorite healthy breakfast choices have a lot of fiber, like oatmeal and granola and walnuts. I read that fiber can interfere with Synthroid absorption.

When I discovered coffee also was prohibited for at least an hour after taking the pill, that did it! No more morning Synthroid for me. Why don’t doctors know these things?

Alternate Dosing Avoids Coffee with Synthroid

A. That is a good question. The FDA includes a warning about fiber reducing levothyroxine (Synthroid) absorption in its prescribing information available to every doctor.

Quite a few foods can affect Synthroid absorption. Coffee and soybeans can significantly reduce the amount of levothyroxine that is absorbed, while vitamin C increases absorption (Skelin et al, Clinical Therapeutics, Feb. 2017). If you like a latte, or put milk on your bran flakes, the plot thickens. Cow’s milk also interferes with optimal levothyroxine absorption (Chon, Endocrine Society, April 1, 2017).

Taking Synthroid at Bedtime

Many people have concluded, just as you did, that no coffee in the morning is a non-starter. Instead, they take their Synthroid in the evening. That eliminates the problem of coffee with Synthroid and works just as well, if not better (Bolk et al, Archives of Internal Medicine, Dec. 13, 2010). A randomized controlled trial concluded that bedtime administration also works equally well for older adults (Frontiers in Medicine, June 23, 2022). The advantage is they don’t have to worry about coffee with Synthroid.

Learn More

We discuss many ways of dealing with hypothyroidism in our eGuide to Thyroid Hormones. You can learn more about the pros and cons of levothyroxine and the best ways to take it.