title: Thyroxine and triiodothyronine content in commercially available thyroid health supplements.
abstract: BACKGROUND
  As defined by the Dietary Supplement Health and Education Act 1997, such substances as herbs and dietary supplements fall under general Food and Drug Administration supervision but have not been closely regulated to date. We examined the thyroid hormone content in readily available dietary health supplements marketed for "thyroid support."
  
  
  METHODS
  Ten commercially available thyroid dietary supplements were purchased. Thyroid supplements were dissolved in 10 mL of acetonitrile and water with 0.1% trifloroacetic acid and analyzed using high-performance liquid chromatography for the presence of both thyroxine (T4) and triiodothyronine (T3) using levothyroxine and liothyronine as a positive controls and standards.
  
  
  RESULTS
  The amount of T4 and T3 was measured separately for each supplement sample. Nine out of 10 supplements revealed a detectable amount of T3 (1.3-25.4 μg/tablet) and 5 of 10 contained T4 (5.77-22.9 μg/tablet). Taken at the recommended dose, 5 supplements delivered T3 quantities of greater than 10 μg/day, and 4 delivered T4 quantities ranging from 8.57 to 91.6 μg/day.
  
  
  CONCLUSIONS
  The majority of dietary thyroid supplements studied contained clinically relevant amounts of T4 and T3, some of which exceeded common treatment doses for hypothyroidism. These amounts of thyroid hormone, found in easily accessible dietary supplements, potentially expose patients to the risk of alterations in thyroid levels even to the point of developing iatrogenic thyrotoxicosis. The current study results emphasize the importance of patient and provider education regarding the use of dietary supplements and highlight the need for greater regulation of these products, which hold potential danger to public health.
authors.affiliation: 1 Department of Endocrinology, Landstuhl Regional Medical Center , Landstuhl, Germany .
authors.forename: Grace Y
authors.initials: GY
authors.lastname: Kang
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Parks
authors.forename: Bader
authors.initials: B
authors.lastname: Fileta
authors.forename: Audrey
authors.initials: A
authors.lastname: Chang
authors.forename: Maged M
authors.initials: MM
authors.lastname: Abdel-Rahim
authors.forename: Henry B
authors.initials: HB
authors.lastname: Burch
authors.forename: Victor J
authors.initials: VJ
authors.lastname: Bernet
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003257:Consumer Product Safety; D019587:Dietary Supplements / Q000009:adverse effects / Q000032:analysis* / Q000191:economics / Q000592:standards; D055664:Electrochemical Techniques; D005506:Food Contamination; D005515:Food Labeling; D006801:Humans; D020407:Internet / Q000191:economics; D008396:Maryland / Q000453:epidemiology; D010353:Patient Education as Topic; D012306:Risk; D013962:Thyroid (USP) / Q000737:chemistry; D013959:Thyroid Diseases / Q000178:diet therapy / Q000517:prevention & control*; D013961:Thyroid Gland / Q000737:chemistry; D013971:Thyrotoxicosis / Q000139:chemically induced / Q000453:epidemiology / Q000209:etiology; D013974:Thyroxine / Q000009:adverse effects / Q000032:analysis* / Q000506:poisoning; D014284:Triiodothyronine / Q000009:adverse effects / Q000032:analysis* / Q000506:poisoning; D014481:United States / Q000453:epidemiology
chemical_list: D013962:Thyroid (USP); D014284:Triiodothyronine; D013974:Thyroxine