Key takeaways:
Thyroid medications like levothyroxine (Synthroid) are used to treat low thyroid levels (hypothyroidism).
If you have borderline hypothyroidism, you may be able to stop your thyroid medication after some time. But most people need thyroid medications long term.
Talk to your prescriber before making any changes to your thyroid medications. This can help you avoid serious health problems and symptoms of hypothyroidism.
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If you have a low level of thyroid hormones in your body, you might have hypothyroidism. Hypothyroidism is a medical condition that can occur when your thyroid gland is underactive or doesn’t work as well as it should.
If you’ve been diagnosed with hypothyroidism, your primary care provider might prescribe medication. This medication will help replace your missing thyroid hormones. The most common medication used to treat hypothyroidism is levothyroxine (Synthroid, Levoxyl, Tirosint). In fact, levothyroxine is one of the most commonly prescribed medications in the U.S.
It’s important to take levothyroxine, and other thyroid medications, exactly as prescribed. These medications help your body function properly. Stopping them suddenly can lead to symptoms of hypothyroidism. And this can lead to some serious health problems. So, make sure to talk with your healthcare team before stopping your thyroid medication.
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What is levothyroxine used for, and how does it work?
Levothyroxine is a synthetic thyroid hormone. It’s the most common medication used to treat hypothyroidism. Thyroid hormones help regulate many of your bodily functions, including metabolism, weight, and body temperature. If you don’t have enough of this hormone, you can develop a range of symptoms including:
Levothyroxine replaces the hormone thyroxine (T4), which converts to the active form of thyroid hormone, triiodothyronine (T3).Taking levothyroxine to replace your missing hormone will bring your thyroid hormones into balance. And it can help relieve these symptoms.
What happens when you stop taking thyroid medication?
If you stop your thyroid medication all of a sudden, symptoms of hypothyroidism will likely return. If hypothyroidism is left untreated, it can lead to many complications including serious health problems. You may experience symptoms like:
Mood swings
Irritability
Slowed thoughts
Weight gain
Dry skin
Cold intolerance
Hair loss
Constipation
Hypothyroidism can also damage your nerves, raise your risk of heart problems, and affect your fertility. Hypothyroidism is also one of the reversible causes of dementia.
And hypothyroidism is especially dangerous if you’re pregnant. It can cause risks to both the pregnant mother and fetus.
Severe hypothyroidism can be life-threatening. In rare cases, your body could slow down so much that you enter a coma. This can even lead to death.
What are the different types of thyroid medications?
Here are the main categories of medications for hypothyroidism:
Synthetic T4 medication: Levothyroxine is the most common synthetic thyroid medication. It’s a lab-made version of the T4 hormone. Levothyroxine has several brand-name products available, including Synthroid, Levoxyl, and Tirosint.
Synthetic T3 medication: A synthetic version of the active T3 hormone is also available. It’s called liothyronine (Cytomel). T3 doesn’t last as long in the body. Also, it needs to be taken more often and can cause more side effects.
Natural T3 and T4 thyroid products: These include desiccated thyroid products. They come from dried animal thyroid glands (usually pigs). These products — including Armour Thyroid and NP Thyroid — naturally contain T3 and T4 hormones. They aren’t approved by the FDA, but they’re still available by prescription only. There aren’t as many studies on these products as there are for levothyroxine. They may also cause more side effects.
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It’s important to remember that levothyroxine remains the first-choice medication to treat hypothyroidism for most people, according to the American Thyroid Association.
Is it possible to stop taking thyroid medication in a safe way?
Yes, there can be a safe way to stop taking thyroid medication. Research shows that some people can safely stop taking thyroid medications. In this review of over 17 individual studies, up to 1 in 3 people were able to stop their thyroid medication. But this was mostly in people with “borderline” hypothyroidism, also called subclinical hypothyroidism. In subclinical hypothyroidism, T4 levels are normal. People with this condition sometimes don’t need thyroid medications at all.
But you should always check with your healthcare team first. Whether or not you’re able to safely stop taking thyroid medication may depend on the reason you’re taking it. If your prescriber decides it’s safe for you to decrease or stop taking your medication altogether, they may suggest you taper your dose. This means that you lower your dose slowly over several weeks, giving your body enough time to adjust.
What happens if you stop taking levothyroxine?
Those who have definite hypothyroidism may not be able to stop taking levothyroxine. Stopping levothyroxine usually leads to the return of hypothyroidism symptoms. In the review mentioned above, only about 1 in 10 people with overt hypothyroidism were able to stop their thyroid medications successfully.
If you’ve had your thyroid completely removed, you’ll need thyroid medications for life. These medications will help your body function normally. If your thyroid was removed due to cancer, treatment may also lower the risk of your cancer coming back.
Talk with your healthcare team before making changes to your thyroid medication. They can help make sure that you’re making the best decision for your health.
What happens if you miss a dose of thyroid medication?
If you miss a dose of thyroid medication, take it as soon as you remember. It’s possible to experience symptoms of hypothyroidism (like fatigue) after a missed dose. If you experience any symptoms, call your primary care provider.
If you miss a dose and it’s almost time for your next dose, skip the missed dose. Take your next dose at your regularly scheduled time. It’s usually not advised to take 2 doses of thyroid medication at the same time. Too much thyroid medication can cause symptoms of hyperthyroidism, including shakiness, sweating, and fast heartbeat.
But if you forget to take your medication for several days, let your prescriber know. They may want to adjust your dose for a few days.
Frequently asked questions
There are a few important thyroid hormones to be aware of:
Thyroid-stimulating hormone (TSH): This is the hormone most frequently checked to monitor your thyroid function and response to medication. TSH tells the thyroid how much thyroid hormone to make.
Triiodothyronine (T3): T3 is the active form of thyroid hormone that binds to thyroid receptors.
Thyroxine (T4): T4 is the inactive form of thyroid hormone that’s converted to the active form, or T3.
In rare cases, untreated hypothyroidism can be fatal. This usually occurs due to the long-term complications of low thyroid hormone on body systems and functions. If you’re thinking about stopping your levothyroxine, talk to your prescriber first to make sure it can be done safely.
How you can safely wean off levothyroxine will depend on your medication dose and your medical history. Your prescriber can help you come up with a plan to safely decrease your levothyroxine to avoid any major effects from stopping the medication. Typically, weaning will involve slowly decreasing your dose over several weeks to allow your body to adjust to the tapering doses.
There are a few important thyroid hormones to be aware of:
Thyroid-stimulating hormone (TSH): This is the hormone most frequently checked to monitor your thyroid function and response to medication. TSH tells the thyroid how much thyroid hormone to make.
Triiodothyronine (T3): T3 is the active form of thyroid hormone that binds to thyroid receptors.
Thyroxine (T4): T4 is the inactive form of thyroid hormone that’s converted to the active form, or T3.
In rare cases, untreated hypothyroidism can be fatal. This usually occurs due to the long-term complications of low thyroid hormone on body systems and functions. If you’re thinking about stopping your levothyroxine, talk to your prescriber first to make sure it can be done safely.
How you can safely wean off levothyroxine will depend on your medication dose and your medical history. Your prescriber can help you come up with a plan to safely decrease your levothyroxine to avoid any major effects from stopping the medication. Typically, weaning will involve slowly decreasing your dose over several weeks to allow your body to adjust to the tapering doses.
The bottom line
Thyroid medications like levothyroxine can help treat hypothyroidism. If you’re interested in stopping levothyroxine and other thyroid medications, talk with your healthcare team first. They can help you decide if this is a safe option for you.
Many people with hypothyroidism can’t stop their thyroid medications without symptoms of hypothyroidism returning. Missing doses of thyroid medication can cause symptoms of hypothyroidism to return. Taking your medication as prescribed can help avoid this.
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References
American Cancer Society. (2024). Thyroid hormone therapy.
Burgos, N., et al. (2021). Clinical outcomes after discontinuation of thyroid hormone replacement: A systematic review and meta-analysis. Thyroid.
Jonklaas, J., et al. (2014). Guidelines for the treatment of hypothyroidism: Prepared by the American Thyroid Association task force on thyroid hormone replacement. Thyroid.
Leung, A. M. (2016). Thyroid emergencies. Journal of Infusion Nursing.
MedlinePlus. (2024). Thyroxine (T4) test.
MedlinePlus. (2024). TSH (thyroid-stimulating hormone) test.
MedlinePlus. (2024). Triiodothyronine (T3) tests.
Safran, M. (2021). A third of patients treated for hypothyroidism may not require thyroid hormone therapy. Clinical Thyroidology for the Public.
