About 12% of the US population will experience thyroid issues in their lifetime – and many of these patients will try thyroid support supplements to help manage symptoms. Be prepared to explain common ingredients in these products, and help patients understand why they aren’t a great idea.
Ashwagandha is typically found in supplements marketed for thyroid support. Early clinical research in people with subclinical hypothyroidism shows that taking ashwagandha root extract 300 mg twice daily for 8 weeks increases triiodothyronine (T3) and thyroxine (T4) levels by 42% and 20%, respectively, and reduces thyroid stimulating hormone (TSH) levels by 17%. But it’s not clear how ashwagandha will affect people with clinical hypothyroidism, or those already taking prescription thyroid medications. Advise these patients to steer clear – ashwagandha might increase both the effects and side effects of prescription therapy.
Also watch out for thyroid extract. It’s derived from animal thyroid gland tissue and contains both T3 and T4 – however, the potency of these hormones varies, making dose titration difficult. Clinical research shows that many patients treated with thyroid extract experience abnormally high levels of T3 and/or T4, raising safety concerns. Plus, some supplements might contain dried or ground raw tissue from animal thyroid glands. Educate patients to avoid supplements with thyroid extract.
Finally, tyrosine is another common ingredient. It’s a precursor for thyroxine and theoretically might boost thyroid hormone levels. But there isn’t any good clinical evidence showing it benefits thyroid conditions. And there are concerns that it might worsen hyperthyroidism and Graves' disease, or alter the treatment of hypothyroidism. Tell patients with thyroid conditions to avoid supplements containing tyrosine.
In addition to specific concerns with many of these ingredients, there have been reports of “thyroid support” products being tainted with clinically significant amounts of thyroid hormones, which can pose additional risks for patients already taking prescription treatments. Advise patients to avoid these types of products, and remind them to always update their healthcare team on any products they try to ensure appropriate monitoring.
The information in this brief report is intended for informational purposes only, and is meant to help users better understand health concerns. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions. Copyright © 2025 NatMed. Commercial distribution or reproduction prohibited. NatMed is the leading provider of high-quality, evidence-based, clinically-relevant information on natural medicine, dietary supplements, herbs, vitamins, minerals, functional foods, diets, complementary practices, CAM modalities, exercises and medical conditions. Monograph sections include interactions with herbs, drugs, foods and labs, contraindications, depletions, dosing, toxicology, adverse effects, pregnancy and lactation data, synonyms, safety and effectiveness.
