Can you take thyroid supplements with levothyroxine?
Taking any other medication or supplement with levothyroxine may cause you to need a higher or lower dose of levothyroxine. Even supplements like calcium or iron can affect absorption of levothyroxine.
According to the complete prescribing information for levothyroxine, many drugs can change the absorption, breakdown or response to levothyroxine. That could mean you get too much effect or too little.
The main problem with over-the-counter supplements is that they are not regulated. They may not contain what they say on the label, or the amount may be higher or lower than stated. According to a review of thyroid supplements in the journal Nutrients, 70% of supplements on the market don’t have the ingredients stated on the label or they have contaminants.
The most common thyroid supplements are:
- L-carnitine
- Myoinositol
- Melatonin
- Resveratrol
- Selenium
Although all of these may have some effect on thyroid hormone, none have been studied enough in people to know exactly how they affect levothyroxine in your body.
If you are taking levothyroxine, it is important to let your doctor know about any new drug or supplement you may take.
References
- American Thyroid Association (ATA). Thyroid Hormone Treatment. Available at: https://www.thyroid.org/thyroid-hormone-treatment/. [Accessed August 9, 2021].
- Benvenga S, Feldt-Rasmussen U, et al. Nutraceutical Supplements in the Thyroid Setting: Health Benefits beyond Basic Nutrition. Nutrients. 2019;11(9):2214. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6770945/.
- U.S. Food and Drug Administration (FDA). Levothyroxine Sodium Tablets. April 2019. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/021116s017lbl.pdf. [Accessed August 9, 2021].
Read next
Does levothyroxine cause weight gain or loss?
In most cases, levothyroxine causes some weight loss. According to the American Thyroid Association, when this medication is started, you may lose up to 10% of your weight. This weight is mainly water weight, since being hypothyroid makes you retain water. Continue reading
What can I eat for breakfast after taking levothyroxine?
Most foods are considered fine to eat for breakfast as long as they are eaten 30 to 60 minutes after taking levothyroxine. Levothyroxine should be taken once a day on an empty stomach in the morning. Continue reading
Can I take other medications with levothyroxine?
Levothyroxine is known to interact with many other medications (called a drug-drug interaction), but there are different kinds of drug-drug interactions. Some interactions require that drugs not be taken at the same time, while other interactions require more frequent laboratory testing or monitoring of your disease symptoms. Continue reading
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Drug information
- Levothyroxine Information for Consumers
- Levothyroxine prescribing info & package insert (for Health Professionals)
- Side Effects of Levothyroxine (detailed)
Related support groups
- Levothyroxine (154 questions, 598 members)