When Should You Take Your Thyroid Medication?

taking thyroid medication at night, thyroid drugs at bedtime
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Readers frequently write to Verywell with thyroid-related questions. Here's a very common one, asking about what time of day is best to take your thyroid hormone replacement medication, along with some thoughts on the subject.

"Is it okay to take the thyroid medication the doctor has prescribed at bedtime, 2 hours after dinner, or even when I wake up in the middle of the night, around 3 to 4 am? I'm always in a rush when I get up in the morning..." 

When Should You Take Your Thyroid Pill?

Standard guidelines recommend that you take your thyroid pill first thing in the morning, on an empty stomach, and wait at least an hour before eating or drinking coffee. You should also wait at least three to four hours before taking any supplements that contain iron or calcium. 

But are the standard guidelines for everyone? Here are some factor to consider. 

First, discuss with your doctor what she/he thinks is the best time to take your medication. Keep in mind, however, that studies have shown that the key with thyroid medication is taking it consistently. That means that you should take it around the same time each day, and in the same way, for example, without food, or several hours apart from eating.

Second, if you have a busy morning, and a tendency to forget your thyroid medication, or need to eat or drink coffee right away, talk with your physician about switching to taking your thyroid medication at bedtime.

Research reported in the journal Clinical Endocrinology found that taking the same dose of levothyroxine at bedtime, as compared to first thing in the morning, might be better for some patients.

A small pilot study (described in Should You Take Your Thyroid Medication at Night?) was prompted by observations that some patients had improved thyroid hormone profiles after they switched from taking their levothyroxine in the morning to bedtime.

The purpose was to look at the impact on thyroid hormone profiles by changing the time levothyroxine was taken from early morning to bedtime. They also evaluated the impact of this change on the circadian rhythm of TSH and thyroid hormones and thyroid hormone metabolism.

The small study was fairly conclusive in its findings. Researchers reported that taking medication at bedtime, rather than the morning, results in "higher thyroid hormone concentrations and lower TSH concentrations." TSH decreased and Free T4 levels rose in all patients by changing thyroxine ingestion from early morning to bedtime and T3 levels rose in all but one subject. And TSH decreased irrespective of the starting TSH levels, suggesting better absorption of the thyroid medication when taken in the evening. Interestingly, the researchers found that the circadian TSH rhythm, the typical daily fluctuations of TSH that occur during a 24-hour period, did not vary.

The researchers suggested several explanations for the results:

  • Even when waiting at least 30 minutes to eat, breakfast may be interfering with the intestinal absorption of thyroid medication
  • "Bowel motility is slower at night," which means that it takes longer for the levothyroxine tablet to transit through the intestinal system, resulting in longer exposure to the intestinal wall, and therefore, better absorption of the medication.
  • The conversion process of T4 to T3 may be more effective in the evening.

The researchers said these results were "striking" and have "important consequences for the millions of patients who take l-thyroxine daily."

The researchers have suggested that given the results of this pilot study, a large double-blinded randomized study will need to be performed to confirm their results.

Should You Take Your Medication at Bedtime?

Taking medication at bedtime instead of in the morning could have major implications for many thyroid patients.

  • First, it's easier, as you don't have to worry about when to eat breakfast.
  • Second, you can drink coffee as soon as you get up (which is surprisingly important to many Americans!) 
  • Third, it's easier to avoid interactions with medications, high-fiber foods, and supplements like calcium and iron that interfere with thyroid medication absorption.
  • Fourth, it might offer some improvement in symptoms if you are not getting optimal absorption by taking your thyroid medication during the morning.

While this was a small study, it confirms what many patients anecdotally have been reporting for years: they feel better if they take their thyroid medication in the evening, rather than the morning.

What About T3 Drugs?

Studies of nighttime thyroid medication were conducted with levothyroxine. The T4 in levothyroxine must first be converted in the body to the active T3 form, a process that can take days. Thyroid drugs that contain T3 such as liothyronine (Cytomel), and natural desiccated thyroid drugs can by used directly by the body within hours. T3 drugs were not evaluated in the study.

Anecdotally, some thyroid patients have reported improvement in symptoms when taking their T3-based thyroid hormone replacement medications in the evening. But some thyroid patients also find that if they take a medication with T3 later in the day or in the evening, the stimulatory effect of the T3 medication can make it difficult to sleep.

So keep in mind that while it's possible that if a similar study were conducted with T3 drugs, the results could be similar as far as improved absorption. Still, there is some chance that it could impact your sleep quality. Only make such a change after discussing it with your doctor.

Optimally, some doctors have suggested that patients who take medications with T3 split their doses to take them throughout the day, leaving a dose for bedtime. This approach seems to minimize sleep interference.

Again, if you do make a change to how you take your T3 thyroid medication, you'll want to have a reevaluation of blood levels and symptoms after several weeks, to determine if you need to adjust the dosage or timing of your medication.

A Word from Verywell

If you and your physician decide to change to taking your thyroid medication in the evening, be sure to have your thyroid levels evaluated around 8 to 12 weeks after you've made the switch. The blood test results, along with any improvements or worsening of symptoms, will help you and your doctor determine if you need to adjust the dosage or timing of your medication.

Source:

Bolk, Nienke et. al. "Effects of evening vs morning thyroxine ingestion on serum thyroid hormone profiles in hypothyroid patients." Clinical Endocrinology 66 (1), 43–48

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