What Is the Connection Between Melatonin and Your Thyroid?


Melatonin is a hormone released at nighttime by the pineal gland, which is a tiny gland located deep within your brain. The pineal gland is considered the master controller of your body's day-to-day circadian clock, telling you when to sleep and when to wake.

Based on its role in circadian rhythm, nighttime melatonin supplementation is commonly used to treat various sleep-related disorders or problems, such as insomnia, delayed sleep phase syndrome, jet lag, or shift work sleep disorder. However, as experts investigate further about melatonin, they are discovering a potential larger-than-expected "melatonin" influence on the body (other than just regulating your circadian rhythm).

One area of interest is the link between melatonin and thyroid disease, specifically how melatonin affects thyroid hormone production.

Melatonin and Your Thyroid

One animal study in the Journal of Physiology and Pharmacology showed that C cells (which are thyroid cells that release a hormone called calcitonin) actually make melatonin, and this production of melatonin is controlled by thyroid-stimulating hormone (TSH). Furthermore, it was found that melatonin regulates thyroid hormone production in the follicular cells (which are thyroid cells that make thyroid hormone).

Other scientific data available suggests that melatonin serves as an antioxidant, protecting the thyroid gland from oxidative stress, which occurs in the course of thyroid disease.


Keep in mind that while the role of melatonin as an antioxidant and thyroid hormone regulator is interesting, it has not been fully deciphered, so does not translate into the fact that patients with thyroid disease should take melatonin—a far stretch at this time.

Instead, experts believe that the connection between your thyroid health and melatonin is complex and dependent on a number of factors like the dose of melatonin, your immune system (whether it is healthy or suppressed), and whether you have any underlying health conditions, amongst others.

Nevertheless, if you have thyroid disease, your doctor may recommend low doses of melatonin more for the goal of helping you sleep (not for its other roles as an antioxidant or thyroid hormone regulator), since we know quality sleep can help balance and restore your hormone system.

Supplementing with Melatonin

If your doctor recommends melatonin, at the minimum amount necessary to improve your sleep quality, he will likely advise you to take a low dose (between 0.1 and 0.5 mg), around 11 p.m. at night, or an hour before you go to bed (whichever is earlier). This allows you to have a "melatonin surge" at the time the body would naturally produce it. Higher doses of melatonin may actually alter your body's normal day/night melatonin levels.

Of course, it's essential to only take melatonin under the care of your doctor. Melatonin may not be safe for people taking Coumadin (warfarin) or antiseizure medications. Be sure to not take melatonin liberally or administer to your children simply because it's "natural" or available over-the-counter. 

Side Effects

Melatonin is not FDA-approved, meaning it has not gone through a rigorous scientific process confirming its safety and effectiveness. That said, melatonin is generally well-tolerated, although there are some potential side effects that you should review with your doctor before taking a dose.

It's also recommended that pregnant or lactating women not take melatonin.

Some of the main side effects from melatonin supplementation include:

  • Morning grogginess
  • Vivid dreams and nightmares
  • Headache
  • Confusion
  • Fragmented sleep

If you are experiencing these side effects, and they are only mild, talk with your doctor, as lowering your dose may be a sensible next step. 

A Word From Verywell

Melatonin has received a lot of hype within both the medical community and even on social media. Keep in mind, though, besides its role in managing sleep disorders, it's unclear how it affects any one person's thyroid health. Until then, be sure to only take melatonin under the care of your doctor. 

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