Can Ibuprofen, Naproxen and and Aspirin Affect Your Thyroid?

pain relievers, nsaids, ibuprofen, naproxen, thyroid
Bjarte Rettedal / Getty Images

Nonsteroidal anti-inflammatory drugs, or NSAIDs (pronounced en-saids), are drugs used to reduce inflammation and pain. They can also lower fevers. 

When you have an ache or pain, you may reach for a common over-the-counter NSAID like aspirin, ibuprofen, or naproxen. Or if you have more significant pain and inflammation, your doctor may give you a prescription NSAID. But do they affect your thyroid? 

Researchers set out to answer that question. A study was carried out to determine the effects of NSAIDs on thyroid levels.

The NSAIDs tested as part of the research study were:

  • Over-the-Counter NSAIDS
    • Aspirin     
    • Ibuprofen (Brand name: Advil) 
    • Naproxen (Brand names: Aleve, Naprosyn, Anaprox)
  • Prescription NSAIDs
    • Salsalate (Brand names: ‎Disalcid, Salflex) 
    • Meclofenamate (Brand name: Meclomen)
    • Indomethacin ( Indocin, Tivorbex)

Twenty-five healthy subjects underwent a single-dose study and/or a one-week study. Total and free T4 and T3 thyroid hormones as well as thyroid stimulating hormone (TSH) levels were analyzed over an eight-hour period after a single dose, and daily in the one week study.

The Results

The researchers found that:

  • Ibuprofen, naproxen, and indomethacin either as a single dose or over a week did not change the levels of any of the hormones measured.
  • Various total and free thyroid hormone measurements were decreased by single doses of aspirin and salsalate and increased by meclofenamate.
  • Treatment for one week with aspirin or salsalate decreased total T4, total T3, free T3, and TSH. Only the salasate lowered free T4 levels, 

The study confirmed that aspirin, salsalate, and meclofenamate affect total and free thyroid hormone measurements.

What This Means for Patients

Was this page helpful?
Article Sources
  • While more studies are needed to evaluate longer-term effects on thyroid function, if you need to use an NSAID drug, you may want to choose over-the-counter ibuprofen or naproxen or have your physician prescribe indomethacin. And, if you are taking aspirin, salsalate, or meclofenamate regularly, you should discuss the possible implications for your thyroid test results and thyroid function with your physician. 
  • Samuels, MH et al. "Variable Effects of Nonsteroidal Antiinflammatory Agents on Thyroid Test Results," The Journal of Clinical Endocrinology & Metabolism, Vol. 88, No. 12 5710-5716 December, 2003