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Hormones Present in Weight Loss Supplements Warn Health Experts

Tim Boyer's picture
Thyroid hormone hidden in weight loss pills

Do you use over-the-counter weight loss supplements marketed on their labels as containing a "thermogenic weight-loss agent" or "hard-core thermogenic," or “metabolic fat burner”? If so, then you may be at risk of seriously overdosing on this one hormone that health experts are discovering is hidden in some weight loss supplements.


According to a new study presented at the 2015 International Thyroid Congress and Annual Meeting of the American Thyroid Association in Orlando, Florida last week, health experts report that while investigating what is actually inside some of the more-popular brands of OTC weight loss supplements, that they detected unsafe levels of thyroid hormones that could be toxic to unsuspecting consumers.

The meeting’s abstract about the study, states that nearly one-third of the sampled nonprescription U.S. weight loss products tested contained unlabeled thyroid hormone content in doses that may result in clinically significant thyrotoxicosis. The researchers concluded that increased regulation of weight loss supplements is needed to ensure the safety of consumers ingesting nonprescription weight loss aids.

So what is it about thyroid hormones that can be unsafe? Thyroid hormones produced naturally in the body or as a prescription by a licensed physician can be safe and beneficial for many patients with a thyroid problem.

The thyroid gland is a butterfly-shaped endocrine gland located at the base of the neck that produces a number of thyroid hormones of which one is called “Thyroxine” or “T4.” The thyroid is of special importance in running your body like a well-oiled machine, especially due to its primary job of regulating your cellular metabolism. If your thyroid is sluggish, then so will be your metabolism; and as a result, you will experience weight gain and difficulty in getting it off.

However, extra thyroid hormone in the wrong hands (and body) can be harmful rather than helpful. According to a quote by one of the study’s co-authors attributed to a Medscape interviewed article about the supplement study presentation, if someone is being treated for a thyroid problem or has relatively normal thyroid hormone levels in their body and begins taking a supplement with added thyroid hormone, the body can reach toxic levels that can result in a medical emergency.

"Effects may include signs and symptoms of thyrotoxicosis, such as weight loss, palpitations, heat intolerance, menstrual irregularities, and if they are used over a prolonged period of time or in high doses acutely, atrial fibrillation and bone loss," states senior author Angela Leung, MD of UCLA. “Thyroid hormones are prescription-only medications that should be used only in the setting of conditions requiring thyroid-hormone replacement, such as hypothyroidism and thyroid cancer management."

So why are some makers of weight loss supplements slipping thyroid hormones into their products? It is likely due to TV show episodes from The Dr. Oz Show and other media about how that having a sluggish thyroid gland may be a cause of weight gain.


According to The Dr. Oz Show, you may have a sluggish thyroid, if you have the following common symptoms that may indicate that your thyroid is not working as well as it should:

• Fatigue

• Weight gain

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• Cold Sensitivity

• Brittle skin, hair and nails

• Constipation

In addition, you can also look into a mirror and see if you pass the eyebrow test and the neck test to see if you may be suffering from a sluggish thyroid.


There are also reports of studies that show that inducing hyperthyroidism in obese rodents has led to substantial weight loss—even while on a high-fat diet. Some researchers speculate that brief periods of hyperthyroidism may be feasible in some patients.

However, inducing hyperthyroidism has both its good points and its bad points. The bad points include an increased heart rate, increased body temperature, muscle fatigue, osteoporosis and unwanted mood changes. The good points of hyperthyroidism are that it results in reduced circulating cholesterol levels and weight loss, making it a potential treatment for metabolic syndrome and obesity.

The makers of weight loss supplements are likely viewing exogenous thyroid hormone or a chemical mimic of thyroid hormone as a way to make their products appear not only effective, but can carry the moniker of “natural” since the human body makes its own thyroid hormone.

But again, the researchers presenting the study stress that only a physician can determine and prescribe safe levels of supplemental thyroid hormone, and that taking weight loss supplements containing thyroid hormone can be dangerous and thus avoided altogether.

For an informative article about how you can safely insure that you are getting enough thyroid hormone in case you suspect your weight gain may be due to a sluggish metabolism, here are some recommended foods from Dr. Oz. for your thyroid gland that may boost your metabolism.


2015 International Thyroid Congress and Annual Meeting of the American Thyroid Association; Orlando, Florida. Short Call Poster 54, presented October 22, 2015. “THYROID HORMONE CONTENT OF NONPRESCRIPTION U.S. WEIGHT LOSS PRODUCTS”; C.D. Seger, X. He, L. Braverman, M.W. Yeh, C. Rhee, and A.M. Leung (note: scroll down to page 23 of the 28-page pdf for the abstract).

Medscape News: “Thyroid Hormone Common Contaminant in Weight-Loss Supplements