Medically reviewed by Sally Chao, MD. Last updated on Aug 22, 2023.
Official answer
by Drugs.com
Armour Thyroid contains two different thyroid hormones derived from pigs, T3 and T4, and T4 will remain in your system longer than T3.
- Most people will clear T3 from the body in around 4 days.
- T4 is eliminated in around 4 to 5 weeks for people with a normally functioning thyroid. Those with an overactive thyroid (hyperthyroidism) will clear T4 quicker (2 to 3 weeks), but it may take around 6 to 7 weeks for people with an underactive thyroid (hypothyroidism) to eliminate T4.
However, these are estimates based on the half-lives of these compounds. The processes involved in absorbing, utilizing and eliminating this combination of thyroid hormones is complex and sensitive, and can be altered by factors including your weight, age, thyroid function, underlying diseases and other medications, such as:
- Birth control pills
- Blood thinners
- Diabetes medications
- Aspirin
- Steroids
- Iodine-containing medications
The time it takes to eliminate these hormones can vary depending on these and other factors. For example, thyroid hormones are eliminated more slowly in people with hypothyroidism compared to those with normal thyroid function.
Armour Thyroid also contains other ingredients. Other ingredients include:
- Calcium stearate
- Dextrose
- Microcrystalline cellulose
- Sodium starch glycolate
- Opadry white (a film coating)
Armour Thyroid is mainly excreted through urine.
People who are prescribed Armour Thyroid or the FDA-approved synthetic thyroid hormones, such as levothyroxine, which are absorbed similarly, generally achieve steady levels of the hormone within 6 weeks of starting treatment.
References
- Allergan. Armour® Thyroid (thyroid tablets, USP). June 2018. Available at: https://media.allergan.com/actavis/actavis/media/allergan-pdf-documents/product-prescribing/06-2018-Armour-Thyroid-PI-final.pdf. [Accessed August 25, 2021].
- Drugs.com. Thyroid, desiccated. October 2020. Available at: https://www.drugs.com/ppa/thyroid-desiccated.html. [Accessed August 25, 2021].
- U.S. Food and Drug Administration (FDA). CYTOMEL®. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2002/10379s47lbl.pdf. [Accessed August 19, 2021].
- American Thyroid Association (ATA). Hypothyroidism: A Booklet for Patients and Their Families. 2019. Available at: https://www.thyroid.org/wp-content/uploads/patients/brochures/Hypothyroidism_web_booklet.pdf. [Accessed August 19, 2021].
- Colucci P, Yue CS, Ducharme M, Benvenga S. A Review of the Pharmaco*kinetics of Levothyroxine for the Treatment of Hypothyroidism. Eur Endocrinol. 2013;9(1):40-47. doi: 10.17925/EE.2013.09.01.40.
- Jonklaas J, Bianco AC, Bauer AJ, et al. Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement. Thyroid. 2014;24(12):1670-1751. doi: 10.1089/thy.2014.0028.
- Drugs.com. Armour Thyroid. May 3, 2021. Available at: https://www.drugs.com/mtm/armour-thyroid.html. [Accessed August 25, 2021].
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FAQs
Official answer. Armour Thyroid contains two different thyroid hormones derived from pigs, T3 and T4, and T4 will remain in your system longer than T3. Most people will clear T3 from the body in around 4 days. T4 is eliminated in around 4 to 5 weeks for people with a normally functioning thyroid.
What happens when you stop taking Armour Thyroid? ›
If you suddenly stop your thyroid medication, you may be at risk of potentially serious symptoms, including: Blood pressure changes. Fatigue, muscle weakness or joint pain. Depression.
How long does it take thyroid medication to leave your system? ›
Short-term effects
The half-life of levothyroxine is 6-7 days, which means it takes about 4-5 weeks for your body to rid itself of levothyroxine. Cytomel has the shortest half-life, about three days; thus, the majority of Cytomel will be out of your body within two weeks.
How long does Armour Thyroid work? ›
Does Armour® Thyroid work immediately? Armour can take 2 to 3 weeks before you feel the full benefit. We recommend re-testing your thyroid levels after eight weeks if you start a new prescription or if you have a change in dose or medication.
What to avoid when taking Armour Thyroid? ›
Food can limit the absorption of these hormones from the stomach. Examples of interacting foods include, but may not be limited to, soy protein, soy infant formulas, high fiber foods, liquid nutrition shakes, and walnuts. To avoid interactions with food, take Thyroid hormones 1 hour before any food.
Why is Armour Thyroid not recommended? ›
Taking Armour Thyroid may worsen cardiovascular disease in certain cases. This is particularly true for older adults and for those with a history of cardiovascular disease. Additionally, Armour Thyroid medication may worsen symptoms for people with diabetes.
What is the thyroid belly? ›
Sometimes, your thyroid doesn't perform as effectively as it should, producing fewer hormones and leading to a condition known as hypothyroidism [3]. An underactive thyroid not only impedes many of your body's functions, but it can also cause abdominal weight gain.
What happens if I miss 3 days of thyroid medication? ›
Thyroid hormone medications replace thyroid hormone when your body doesn't have enough. Missing one dose of your thyroid medication is usually not a big deal. But missing multiple doses can lead to symptoms like feeling cold, tired, or constipated. And stopping altogether can be dangerous to your health.
What does a thyroid storm feel like? ›
Common signs and symptoms of thyroid storm include: Having a high fever — a temperature between 104 degrees to 106 degrees Fahrenheit is common. Having a rapid heart rate (tachycardia) that can exceed 140 beats per minute. Feeling agitated, irritable and/or anxious.
Is 30 mg of Armour Thyroid a lot? ›
If your doctor prescribes Armour Thyroid for your hypothyroidism, your starting dose will likely be 30 mg. Typically, you'll take this once per day. Every 2–3 weeks, your doctor may recommend increasing your daily dose. They'll usually increase it by 15 mg until your thyroid hormone level gets to the usual range.
Thyroid medication should be taken on an empty stomach, around the same time each day. Afterwards, we recommend avoiding eating or drinking for 30-60 minutes. Most of our patients take thyroid hormone in the morning upon waking. Breakfast, including any coffee or milk, can be eaten 30-60 minutes later.
Can you switch from Armour Thyroid to levothyroxine? ›
Armour Thyroid and levothyroxine aren't interchangeable. But it's possible to switch from one medication to the other. This should be done under the supervision of a healthcare provider and will require a new prescription. Your dose will change if you switch medications.
What happens if you stop taking Armour Thyroid suddenly? ›
When your doctor asks you to stop your thyroid medication, your hormone level will decrease significantly, and this may lead to signs and symptoms of acute hypothyroidism. Weakness, lethargy, cold intolerance, paleness, dry skin, coarse hair, and constipation can occur with acute hypothyroidism.
Can I take vitamin D with my Armour Thyroid? ›
Interactions between your drugs
No interactions were found between Armour Thyroid and Vitamin D3. However, this does not necessarily mean no interactions exist. Always consult your healthcare provider.
Does caffeine interfere with Armour Thyroid? ›
This could make the drug less effective. Avoid drinking caffeine-containing drinks for at least 30–60 minutes after taking Armour Thyroid. Armour Thyroid may also interact with soy baby formula.
Does Armour Thyroid cause weight gain? ›
Weight gain is an uncommon side effect of Armour Thyroid but may occur if the dosage of Armour Thyroid is not supplementing your low thyroid levels enough. It is not uncommon for people with low thyroid levels to lose up to 10% of their body weight when starting thyroid medications, such as Armour Thyroid.
Does Armour Thyroid cause hair thinning? ›
Hair loss may occur during the first few months of treatment.
