Levothyroxine is a synthetic version of a thyroid hormone called thyroxine. Doctors usually prescribe levothyroxine to help treat an underactive thyroid gland (hypothyroidism). Levothyroxine comes in the form of tablets and capsules.
Doctors generally recommend taking levothyroxine on an empty stomach. This is because food and drinks containing caffeine may interrupt or cause problems with how your body absorbs the medication. Taking levothyroxine while eating a meal or shortly afterward may prevent its desired effect.
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Your body is better at absorbing levothyroxine (Levoxyl) on an empty stomach. Therefore, doctors typically recommend taking this medication once per day before breakfast.
Having an empty stomach also reduces the risk of the drug interacting with any other medications or substances that may be in your foods and drinks.
This is because the acidity of your stomach is typically higher when you have an empty stomach. Eating can change your stomach acidity and reduce the absorption capacity of your gut. Caffeinated drinks like tea and coffee can make it more difficult for your body to absorb levothyroxine properly.
To make sure your stomach is empty when you take levothyroxine, experts recommend taking the medication about 30–60 minutes before having breakfast or any drink that contains caffeine, such as tea, coffee, or energy drinks.
Some people with gastrointestinal disorders or who work night shifts may have difficulty taking levothyroxine early in the morning. In this case, they should take levothyroxine at least 3–4 hours after dinner to ensure they are on an empty stomach.
People should aim to take levothyroxine consistently at the same time every day without missing any doses. Repeatedly forgetting to take your medication can make you feel unwell and cause symptoms to return.
Possible medication interactions
Levothyroxine can interact with several medications. If you take supplements containing iron or calcium, take them at least 4 hours before or after taking levothyroxine.
Other medications that can interact with levothyroxine may include:
antacids containing aluminum or magnesium, such as Maalox and Mylanta
drugs for treating diabetes like metformin (Riomet)
medications containing estrogen
certain medications for cancer, including fluorouracil (Carac)
You should always tell doctors you take vitamins, supplements, or herbal products to avoid possible interactions with levothyroxine. It’s also important to make doctors aware of any prescription or nonprescription medications you are taking.
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Liothyronine contains synthetic T3 hormones instead of the T4 hormones in levothyroxine. Liothyronine is a medication for helping treat hypothyroidism. Similar to levothyroxine, this drug has several possible interactions with other drugs.
Liothyronine may have a higher risk of toxicity than levothyroxine, which is rare. People who take liothyronine should have regular blood tests to check their T3 hormone levels.
DTE, also known as Armour Thyroid, is a natural alternative to levothyroxine. It contains a dried thyroid extract made from pigs’ thyroid glands. DTE contains both triiodothyronine (T3) and thyroxine (T4). A 2021 study found that people with hypothyroidism felt better from taking DTE instead of levothyroxine.
However, DTE does not have Food and Drug Administration (FDA) approval as a treatment option for hypothyroidism, and more research is necessary.
Speak with a doctor if you experience any side effects after taking levothyroxine that stop you from taking your medications daily. They can advise you about alternative treatment options for your condition and the steps you can take to improve your symptoms.
Summary
Levothyroxine is a medication for treating hypothyroidism. Doctors typically recommend taking levothyroxine on an empty stomach, as food and caffeinated drinks can affect how your body absorbs it. People should take levothyroxine at least 30 minutes before breakfast or 4 hours after dinner.
Levothyroxine can interact with several medications and supplements, including iron, calcium, antacids, proton pump inhibitors, and hormone therapies, like hormonal birth control. A person should always tell a doctor if they are taking any supplements or medications to prevent any interaction with levothyroxine.
Some alternative treatment options for hypothyroidism include liothyronine and DTE. However, levothyroxine typically remains the most popular treatment for this condition as liothyronine has higher toxicity and DTE is currently not FDA-approved.
