Levothyroxine oral tablets dosage: A detailed guide
Levothyroxine oral tablets are a generic medication for the brand names Euthyrox, Levo-T, Levolet, Levoxyl, Synthroid, and Unithroid.
This article describes levothyroxine’s dosages, strengths, and details on how to take it. You’ll also find information on cost savings and coupon options for levothyroxine.
If you want to know more about levothyroxine, see this overview article. It covers details about the drug’s uses, side effects, ways to save on cost, and more.
Boxed warning: Not to be used for weight loss or treating obesity
Levothyroxine has a boxed warning about not using it to aid in weight loss or to treat obesity. Boxed warnings are serious warnings from the Food and Drug Administration (FDA). See the end of this article for more information.
Form and strengths of levothyroxine
Levothyroxine oral tablets come as follows:
- Form: a tablet that you swallow
- 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
Dosage of levothyroxine
This article describes the usual recommended dosages* for levothyroxine oral tablets.
If your doctor prescribes this medication, they’ll determine the dosage that’s best for you. Do not change your dosage of levothyroxine oral tablets without your doctor’s recommendation.
* The drugmaker provides these recommended dosages. If your doctor prescribes levothyroxine, be sure to take the dosage they prescribe for you.
Usual recommended dosages of levothyroxine in adults
Usually, doctors will start by prescribing a low dosage of levothyroxine oral tablets. Then, they’ll adjust the dosage over time until they reach the right dosage. Ultimately, your doctor will prescribe the smallest dosage of levothyroxine oral tablets that gives the desired outcome.
The information below describes dosages that are commonly prescribed. That said, always take the dosage your doctor prescribes for you. Your doctor will determine the dosage that best meets your needs.
Levothyroxine dosage chart for adults
Doctors prescribe levothyroxine in micrograms (mcg). This is unlike most other drugs, which are prescribed in milligrams (mg).
The dose depends on your body weight in kilograms (kg). (For reference, 1 kg equals about 2.2 pounds [lb].) Your doctor will prescribe levothyroxine oral tablets as mcg per kg body weight per day (mcg/kg/day).
The dosage chart below describes levothyroxine’s recommended dosages for adults:
|Condition||Starting dosage||Maintenance dosage||Maximum dosage|
|hypothyroidism (underactive thyroid)||1.6 mcg/kg/day||based on your thyroid stimulating hormone (TSH) level*||300 mcg/day†|
|thyroid cancer||based on your TSH level*||based on your TSH level*, but usually 2 mcg/kg/day or greater||based on your TSH level*|
* During levothyroxine treatment, your doctor will order blood tests to check the TSH level in your body. They’ll adjust your levothyroxine dose based on these test results.
† In rare cases, a levothyroxine dose above 300 mcg/day may be necessary. Always take the dosage your doctor prescribes for you.
Dosages of levothyroxine in children
Levothyroxine is prescribed to treat hypothyroidism in children. Doctors determine children’s doses by the child’s body weight and age.
Levothyroxine dosage chart by weight and age
The dosage chart below describes levothyroxine dosage in children by weight and age:
|Child’s age||Levothyroxine dosage|
|0 to 3 months||10 mcg/kg/day to 15 mcg/kg/day|
|3 to 6 months||8 mcg/kg/day to 10 mcg/kg/day|
|6 to 12 months||6 mcg/kg/day to 8 mcg/kg/day|
|1 to 5 years||5 mcg/kg/day to 6 mcg/kg/day|
|6 to 12 years||4 mcg/kg/day to 5 mcg/kg/day|
|older than 12 years before puberty and growth are complete||2 mcg/kg/day to 3 mcg/kg/day|
|older than 12 years after puberty and growth are complete||1.6 mcg/kg/day|
Dosage adjustments for levothyroxine
Your doctor will prescribe a dosage of levothyroxine oral tablets based on several factors, including:
- the specific condition being treated and its severity*
- your age†
- your body weight
- other health conditions you may have, including:
- heart disease
- hyperactivity (in children)
* For example, if you’ve had severe hypothyroidism for a long time, your doctor may prescribe a lower levothyroxine starting dose.
† Doctors may prescribe a lower levothyroxine starting dose for adults ages 65 years and older.
Missed dose of levothyroxine
Talk with your doctor or pharmacist about any missed doses of levothyroxine oral tablets. They can recommend whether you should take the missed dose or skip it and take your next dose as scheduled.
For tips on how to plan your doses of levothyroxine oral tablets and avoid missed doses, read this article. You could also try downloading a reminder app on your phone or setting an alarm.
How levothyroxine is taken
Levothyroxine oral tablets are taken by mouth. They’re taken once per day.
You should take levothyroxine on an empty stomach, preferably 30 to 60 minutes before your first meal of the day. This can help the drug work more effectively because it keeps a consistent amount of the drug in your body.
Do not split or chew the tablets. If it’s hard for you to swallow tablets, you may crush them. Then, mix them with 1 teaspoon (tsp) to 2 tsp of water. Swallow the mixture immediately.
Get tips in this article on how to swallow medications that come in pill form.
Also, be sure to talk with your doctor or pharmacist if you’re having difficulty taking your medication. They can offer recommendations about taking it.
Visit this page to access Optum Perks coupons and get price estimates for levothyroxine when you use the coupons. These coupons can provide significant savings on your prescription costs.
Note: Optum Perks coupons cannot be used with any insurance copays or benefits.
Frequently asked questions
Below are answers to some commonly asked questions about levothyroxine oral tablets and their dosage.
Is there a recommended levothyroxine dosage for weight loss?
Levothyroxine does not have a recommended dosage for weight loss. It should not be taken for weight loss. In fact, the drug has a boxed warning about not using it for weight loss or to treat obesity. Boxed warnings are serious warnings from the Food and Drug Administration (FDA).
Recommended doses for levothyroxine are not effective for weight management in people with typical thyroid function. And taking higher than recommended doses of levothyroxine can cause serious or even life threatening side effects.
View this article for details about the drug’s side effects. Also, the “Overdose of levothyroxine” section below has a list of possible symptoms from taking too much levothyroxine.
Talk with your doctor if you want to learn about safe and effective methods for weight management.
What should I know about calculating levothyroxine doses?
Levothyroxine doses are calculated using your body weight in kilograms (kg). (For reference, 1 kg equals about 2.2 pounds [lb].)
Your doctor may use a dose calculator to determine your levothyroxine dose. A dose calculator helps doctors quickly calculate your starting dose based on the recommended dose for your weight. See the “Dosage of levothyroxine” section above for details.
You can ask your doctor or pharmacist for more information about how they calculate doses of levothyroxine.
Will my doctor be adjusting my levothyroxine dose based on my TSH level? Are there adjustment guidelines to follow?
Yes, your doctor will adjust your levothyroxine dose based on your thyroid stimulating hormone (TSH) level.
While you’re taking levothyroxine, your doctor will order blood tests to check your TSH level. Your doctor may adjust your dose every 4 to 6 weeks based on your test results. Always follow your doctor’s instructions for lab tests and dosage.
Talk with your doctor or pharmacist if you have more questions about levothyroxine dosing and TSH tests. You can learn more about recommended levothyroxine dosages in the “Dosage of levothyroxine” section above.
What is the lowest dose, highest dose, and ‘normal’ dose of levothyroxine?
The lowest available dosage of levothyroxine oral tablets is 25 micrograms (mcg) per day. The highest dosage is 300 mcg per day.
There’s no “normal” dose for levothyroxine. A person’s levothyroxine dose depends on the level of thyroid stimulating hormone (TSH) in their body. (See the question about TSH just above to learn more.) It also varies based on age and body weight.
You can see a list of levothyroxine oral tablet strengths in the “Form and strengths of levothyroxine” section above. For the usual recommended dosages, check out the “Dosage of levothyroxine” section above.
You can also talk with your doctor or pharmacist to learn more.
Is levothyroxine used long term?
Yes, doctors typically prescribe levothyroxine oral tablets as a long-term treatment.
If you and your doctor determine that it’s safe and effective for your condition, you’ll likely take the medication long term.
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Overdose of levothyroxine
It’s important that you do not take more levothyroxine oral tablets than your doctor prescribes. Doing so can lead to serious side effects.
Symptoms of levothyroxine overdose
Symptoms caused by an overdose can include:
- excessive sweating
- feeling anxious or irritable
- tremors (shaky limbs or shakiness)
- muscle spasm
- fast, slow, or irregular heart rate
- feeling confused or disoriented
- heart attack
- cardiac arrest
- bleeding in your head
In rare cases, death has occurred due to levothyroxine overdose.
What to do in case you take too much levothyroxine
If you think you’ve taken too much levothyroxine, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at the American Association of Poison Control Centers. You can also use its online resource. If you have severe symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.
What to ask your doctor
This article describes the usual recommended dosages for levothyroxine oral tablets. If your doctor prescribes this medication, they’ll determine the dosage that’s best for you.
Do not change your dosage of levothyroxine oral tablets without your doctor’s recommendation. You should take levothyroxine oral tablets exactly as your doctor prescribes. You can review the recommended dosages in the “Dosage of levothyroxine” section above.
Let your doctor know if you have concerns or questions about your treatment plan.
Here’s a list of some possible questions you may want to ask your doctor:
- If I have side effects from levothyroxine, is there a lower dose I can take?
- How often will I need my levothyroxine dosage adjusted during treatment? Is it possible to reach a “steady” dose with this drug?
- If I’m taking other medications, will I need a different levothyroxine dosage?
Levothyroxine should not be used for weight loss or treating obesity. Recommended doses of levothyroxine are not effective for weight loss in people with typical thyroid function. And taking more than the recommended doses of this medication can cause serious or even life threatening side effects.
Talk with your doctor for more information about levothyroxine’s boxed warning.
Disclaimer: Optum Perks 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.
- Levothyroxine sodium tablets, for oral use. (2022). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/55cebc88-0514-4940-b974-ec7f0467d10e/spl-doc