Unithroid (levothyroxine) is a brand-name drug prescribed for certain thyroid conditions in adults and some children. It comes as an oral tablet that’s typically taken once per day. The dosage can vary depending on certain factors.

Unithroid is approved by the Food and Drug Administration (FDA) to treat:

Unithroid belongs to a drug class called thyroid hormones. Unithroid is available in a generic version called levothyroxine.

Keep reading for specific information about the dosage of Unithroid, including its strengths and how to take the medication. For a comprehensive look at Unithroid, see this article.

Note: This article describes typical dosages for Unithroid provided by the drug’s manufacturer. When taking Unithroid, always follow the dosage prescribed by your doctor.

The information below describes Unithroid’s typical dosages and other details about the drug.

Unithroid form

Unithroid comes as an oral tablet.

Unithroid strengths

Unithroid comes in the following strengths:

  • 25 micrograms (mcg)
  • 50 mcg
  • 75 mcg
  • 88 mcg
  • 100 mcg
  • 112 mcg
  • 125 mcg
  • 137 mcg
  • 150 mcg
  • 175 mcg
  • 200 mcg
  • 300 mcg

Typical dosages

Typically, your doctor will start by prescribing you a low dosage. Then, they’ll adjust it over time to reach the amount that’s right for you. Your doctor will ultimately prescribe the smallest dosage that provides the desired effect.

The following information describes dosages that are commonly prescribed or recommended in adults. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Dosage for hypothyroidism

Doctors may prescribe Unithroid to treat hypothyroidism.

If your doctor prescribes Unithroid for hypothyroidism, your starting dose will likely be 1.6 mcg per kilogram of body weight (mcg/kg). Typically, you’ll take this once per day.

For example, if you weigh 70 kg (about 154 pounds), you’ll take 100–125 mcg per day. Your doctor will check your thyroid hormone levels during treatment. If necessary, they may increase your daily dosage by 12.5–25 mcg once every 4–6 weeks. The maximum recommended dosage of Unithroid is 300 mcg per day.

If you are pregnant or have certain health conditions, such as heart disease, your doctor may recommend a different starting dosage.

For more information about your specific dosage, talk with your doctor.

Dosage for TSH suppression

Doctors may prescribe Unithroid to suppress thyroid-stimulating hormone (TSH) in certain types of thyroid cancer.

For this use, the starting dose will likely be the same as the starting dose for hypothyroidism: 1.6 mcg/kg. Typically, you’ll take this once per day.

Once every 4–6 weeks, your doctor may increase your daily dosage by 12.5–25 mcg as necessary. The maximum recommended dosage of Unithroid is 300 mcg per day.

For more information about your specific dosage, talk with your doctor.

Children’s dosage

Unithroid is approved to treat hypothyroidism and TSH suppression in certain children ages 17 years and younger.

The dosage is based on the child’s body weight in kilograms (kg). It’s measured in milligrams per kg of body weight (mg/kg).

The table below lists the typical dosing schedule for children taking Unithroid for hypothyroidism.

Age Daily dose
0–3 months10–15 mcg/kg
3–6 months8–10 mcg/kg
6–12 months6–8 mcg/kg
1–5 years5–6 mcg/kg
6–12 years4–5 mcg/kg
more than 12 years old but still going through puberty2–3 mcg/kg
more than 12 years old and completed puberty1.6 mcg/kg

If your child is taking Unithroid for TSH suppression, their dosage may vary from the chart listed above. Talk with your child’s doctor if you have questions about their dosage.

Long-term treatment

Unithroid is meant to be taken as a long-term treatment. If you and your doctor determine that Unithroid is safe and effective for you, you’ll likely take it long term.

Before you start taking Unithroid, your doctor will discuss your treatment plan with you.

The Unithroid dosage your doctor prescribes will depend on several factors. These include:

  • your age
  • your body weight
  • how your body responds to Unithroid
  • the type and severity of the condition you’re taking Unithroid to treat
  • other medications you take
  • side effects you may experience with Unithroid

Other medical conditions you have can also affect your Unithroid dosage.

Dosage adjustments

Your doctor may need to adjust your dosage if you take certain medications, such as liver enzyme inhibitors or inducers. (A liver enzyme is a type of protein in the liver that breaks down medications.) These drugs can affect the level of Unithroid in your body.

Your doctor may also need to adjust your dosage if you are pregnant, have certain health conditions, or are 65 years old or older.

Before you start treatment with Unithroid, be sure to tell your doctor about any medications you take and any health conditions you may have.

Unithroid comes as an oral tablet that you swallow whole. Your doctor will likely recommend taking Unithroid on an empty stomach, 30 minutes to 1 hour before breakfast. Taking Unithroid around the same time each day helps maintain a steady level of the drug in your body so it can work effectively.

If you or your child has trouble swallowing the tablets, you can crush the tablet and mix it with 5–10 milliliters (1–2 teaspoons) of water. Swallow the mixture right away, using a dropper or syringe if needed. For more tips on how to swallow pills, see this article.

Do not take Unithroid tablets within 4 hours of taking a supplement containing iron or calcium, such as an antacid. These supplements can affect how well your body absorbs Unithroid.

If you have questions or concerns about how to take Unithroid, talk with your doctor or pharmacist.


Some pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.

If you’re having trouble opening medication bottles, ask your pharmacist about putting Unithroid in an easy-open container. They also may recommend tools that can make it easier to open bottles.

If you miss a dose of Unithroid, call your doctor or pharmacist as soon as you remember. They’ll let you know whether you should take the missed dose or skip it and take your next scheduled dose.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or putting a note where you’ll see it, such as on your bathroom mirror or bedside table. You could also download a reminder app on your phone.

It’s important that you don’t take more Unithroid than your doctor prescribes. For some medications, taking more than the recommended amount may lead to harmful effects or overdose.

Effects of an overdose

Effects of a Unithroid overdose can include:

  • shortness of breath
  • anxiety or nervousness
  • confusion or disorientation
  • blood clot in the brain
  • coma

If you take more than the recommended amount of Unithroid

Call your doctor right away if you believe you’ve taken too much Unithroid. Another option is to call America’s Poison Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.

Below are some frequently asked questions about Unithroid.

Is the dosage of Unithroid similar to the dosage of Synthroid (levothyroxine)?

Yes, the dosages of Unithroid and Synthroid (levothyroxine) are similar. This is because both drugs are oral tablets that contain the same active ingredient, levothyroxine. They also come in the same strengths. As such, with either drug, you’ll likely take it once per day.

To learn more about how these drugs compare, talk with your doctor. For more information about Synthroid’s dosage, see this article.

Can Unithroid be used for Hashimoto’s disease? If so, what’s the dosage?

Yes, Unithroid is approved to treat hypothyroidism, which may be caused by Hashimoto’s disease. Hashimoto’s disease is an autoimmune disease that affects the thyroid gland. It can cause your body to produce too much thyroid hormone. Over time, this causes the thyroid gland to stop working as it should, which leads to hypothyroidism.

For details about the dosage of Unithroid for hypothyroidism caused by Hashimoto’s disease, see “Dosage for hypothyroidism” above.

If you have questions about other treatments for Hashimoto’s disease, talk with your doctor.

The dosages in this article are typical dosages provided by the drug’s manufacturer. If your doctor recommends Unithroid for you, they will prescribe the dosage that’s right for you. Always follow the dosage that your doctor prescribes.

As with any drug, never change your dosage of Unithroid without your doctor’s recommendation. If you have questions about the dosage of Unithroid that’s best for you, talk with your doctor.

Besides learning about dosage, you may want other information about Unithroid. These additional articles might be helpful:

  • More about Unithroid. For information about other aspects of Unithroid, refer to this article.
  • Drug comparison. To find out how levothyroxine (the active drug in Unithroid) compares with Synthroid, read this article.
  • Cost. If you’d like to learn about Unithroid and cost, see this article.
  • Details about hypothyroidism. For details about hypothyroidism, see our list of hypothyroid articles.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.