"Thyroxine and Triiodothyronine Content in Commercially Available Thyroid Health Supplements"
From that article: Dietary and herbal thyroid supplements marketed to improve thyroid health or support thyroid function so as to improve energy and/or promote weight reduction appeal to many patients who are under the misconception that herbalproducts are safer than conventional medications.
Herbscommonly found in the active ingredients were iodine-richsubstances such as kelp or bladderwrack (F. vesiculosus), or substances believed to be thyroid stimulants, Ashwagandha
root (W. somnifera),C. forskohlii, or guggul based on animalstudies. Kelp or bladderwrack are used as a source of iodine in herbal medicine to treat patients with underactive thyroidglands. Large doses of iodine may occasionally precipitate a reversible hyperthyroidism in patients with underlying autoimmune thyroid autonomy.