Thyroxine and Triiodothyronine in Commercially Available Thyroid Supplements?
Hidden hormones could have unintended health consequences
By Tina Beaudoin, ND
About the Author
Tina Beaudoin, ND. Embracing the quote “the essence of life is to care,” Dr. Tina Beaudoin is an asset both to Emerson Ecologics customers and her patients. As part of Emerson’s Medical Education team, Dr. Beaudoin is one of the doctors on staff available for consultations to our practitioner customers. With a special interest in environmental medicine, mental health and women’s health, Dr. Beaudoin has enjoyed being in general medicine practice since 2010. Guided by a proactive healthcare model, Dr. Beaudoin does not simply treat symptoms, but rather is committed to identifying the cause of health issues by actively listening and hearing each patient’s story and then formulating individualized treatment plans.
Dr. Beaudoin received her doctorate in naturopathic medicine from Bastyr University. Just a year prior to starting naturopathic medical school, she didn’t even know the field existed. Tina began her education with a degree in psychology from Ithaca College. Raised with the strong family value of giving to the community, Tina always knew a career in service to others would be a guiding principle in her professional life. She had previously enjoyed working as a residential counselor with children in a group home setting. It was when she attended a lecture on natural medicine in Boston that she had that profound moment when she knew she had found her path, and she has loved every moment since!
Currently serving as the President of the New Hampshire Association of Naturopathic Doctors (NHAND), Dr. Beaudoin is dedicated to improving access to healthcare as well as education. She gives public and corporate lectures on a variety of integrative healthcare topics in her drive to enhance community wellness. Her passion is to create partnerships to build a foundation of health and total wellness for patients and their loved ones.
A New Hampshire native, Tina loves spending time hiking, playing tennis and kayaking in the great New England outdoors. And with two English yellow Labrador Retrievers, it’s no surprise she also enjoys swimming. Cooking whole food dishes using the herbs from her windowsill garden, Tina loves sharing food and time with friends and family. With Tina’s dedicated focus on helping all the people in her life make small, incremental changes to increase their health, she is well on her way to her goal of leaving this world a little better than when she arrived.
A study recently published in the journal Thyroid found potentially dangerous adulteration in many popular thyroid supplements that should be of concern to all integrative practitioners.1 The study looked at 10 commercially available thyroid health supplements sold via local retail stores or the Internet. Using the keywords “thyroid health,” “thyroid supplements,” and “thyroid support,” they found 5 herb-based and 5 desiccated thyroid tissue–based supplements to study. The 5 herb-based products also contained varying amounts of tyrosine and iodine and did not list or indicate that any animal tissue was used in the manufacturing of the products. The 5 products containing thyroid tissue were from bovine sources and described as including “raw thyroid” tissue, concentrate, or powder.
The authors tested 3 samples from each product for thyroid hormones T3 and T4 using high-performance liquid chromatography. Each product was given a unique product identification number to blind laboratory investigators during product testing. Levothyroxine and liothyronine obtained from a local pharmacy served as controls and standards.
The results? Nine out of 10 products tested positive for containing T3, with 4 out of 9 of those products exceeding a total daily dose of 10 µg per day. Five products contained detectable amounts of both T3 and T4. At the daily recommended dose of 4 capsules, one product contained thyroid hormone levels that reached doses restricted to availability by prescription only for both T3 (at >5 µg/d) and T4 (at 25 µg/d). All of the herb-based supplements tested positive for T3, and 2 of these 5 products also tested positive for T4 at levels of 17 µg and 91 µg per day based on daily dose recommendations. The herb-based products contained iodine ranging from 100 mg to 225 mg and L-tyrosine ranging from 150 mg to 1000 mg. The authors noted that guggul (Commiphora mukul), kelp, ashwagandha (Withania somnifera), bladderwrack (Fucus vesiculosis), Coleus forskohlii, and Schisandra chinensis were the herbs commonly found in the botanical formulas.
In the integrative community, it is commonplace to utilize dietary and botanical supplements to help support optimal health and vitality. Thyroid dysfunction is common, with nearly 5% of the US population above the age of 12 years having hypothyroidism.2 The occurrence of hypothyroidism is even greater among older people, affecting 5%-20% of women and 3%-8% of men.3 The implications of this study are significant, as many patients seek integrative care for thyroid health, and according to this study’s results, a practitioner could unknowingly be medicating a patient with active thyroid hormone when recommending a thyroid support supplement.
If you use thyroid support dietary supplements in your practice, ask the manufacturer if the product or its component ingredients have been tested for T3 and T4 adulteration.
This study suggests intentional adulteration of thyroid support supplements with T3 and T4 hormones in 9 out of 10 products sampled. It was alarming to note that the greatest levels of T3 were found not in thyroid glandular extracts but rather in the botanical supplements sampled. Every one of the botanical products sampled tested positive for T3, with the total daily dose ranging from 2.73 µg to 32.13 µg. Four of the products fall within range of or exceed prescription dosing treatment recommendations. The occurrence of only T3 in 4 of the products leads to speculation of selective adulteration of the hormone in these products. The authors also cited cases of adulteration in dietary supplements for weight loss; while not surprising, it is no less concerning. There are also well-documented instances of adulteration among popular botanicals, including ginkgo biloba, saw palmetto, and black cohosh, as well as other product categories such as sexual health and body-building supplements.4-6
This study presents several issues of clinical importance. First is the potential danger of thyrotoxicosis secondary to adulterated thyroid support supplements. Second, this study demonstrates the need for clinicians to ask their patients for a complete list of dietary supplements and recognize the potential dangers that some of these products can pose. Third, clinicians need to discern whether or not the supplements recommended in clinical practice are exactly what they purport to be. Becoming familiar with and confident of the quality practices of preferred supplement manufacturers is of utmost importance.
The study design would have been stronger if it had included a third category of products that contained only tyrosine and iodine. As thyroid hormones are built upon iodine and tyrosine, the authors should ensure that the methods used to evaluate hormone content adequately differentiate between iodine, tyrosine, and true T3/T4 content. This was not discussed in the study but could indicate a potential study flaw.
Ensuring Quality and Purity
In 1994, the Dietary Supplement Health and Education Act (DSHEA) passed historical legislation that granted the US Food and Drug Administration the authority to prohibit unsafe and mislabeled dietary supplements. As of June 2010, all manufacturers are required to be compliant with DSHEA guidelines set for safety, consistency, quality, purity, and potency. However, there is clearly a need for manufacturers to exceed requirements set forth by DSHEA as the 800 plus–page document of guidelines does not guarantee all aspects of quality. Utilizing third-party certifications to verify current Good Manufacturing Practices compliance is one opportunity that manufacturers can employ to raise the bar on quality practices.
There is also latitude in the DSHEA guidelines on frequency of batch testing of raw materials and finished products for purity and potency. Asking manufacturers how often they are testing their materials is another way to help discern quality practices. Does the manufacturer rely on the validity of the certificate of analysis provided by a supplier when purchasing raw materials, or does it utilize in-house or third-party testing laboratories to verify and guarantee quality?
These are just a few of the questions one might consider when trying to determine their level of investment and commitment to quality practices. If you use thyroid support dietary supplements in your practice, ask the manufacturer if the product or its component ingredients have been tested for T3 and T4 adulteration. While there are many very high-quality dietary supplement manufacturers, this article serves as a reminder and opportunity to hold steadfast to quality practices in the dietary supplement industry as we strive to offer our patients the very best care.
This article was a part of the August 2014 special Natural Medicine Journal issue on endocrinology. To see the rest of the special issue, click here.
- Kang GY, Parks JR, Fileta B, et al. Thyroxine and triiodothyronine content in commercially available thyroid health supplements. Thyroid. 2013;23(10):1233-1237.
- Golden SH, Robinson KA, Saldanha I, Anton B, Ladenson PW. Prevalence and incidence of endocrine and metabolic disorders in the United States: a comprehensive review. J Clin Endocrinol Metab. 2009;94(6):1853-1878.
- Laurberg P, Andersen S, Bülow Pedersen I, Carlé A. Hypothyroidism in the elderly: pathophysiology, diagnosis and treatment. Drugs Aging. 2005;22(1):23-38.
- Masada-atsumi S, Kumeta Y, Takahashi Y, Hakamatsuka T, Goda Y. Evaluation of the botanical origin of black cohosh products by genetic and chemical analyses. Biol Pharm Bull. 2014;37(3):454-60.
- Little DP, Jeanson ML. DNA barcode authentication of saw palmetto herbal dietary supplements. Sci Rep. 2013 Dec 17;3:3518.
- Wohlmuth H, Savage K, Dowell A, Mouatt P. Adulteration of Ginkgo biloba products and a simple method to improve its detection. Phytomedicine. 2014;21(6):912-918.