Seen the ads for no-prescription-needed thyroid supplements and wondered if they can help you shed pounds more easily? Don't risk your health, warn endocrinologists who analyzed the supplements and found ingredients that can harm your heart, hormonal balance and even cause anxiety, reported MedPage on Dec. 18.
To conduct the study, Grace Kang, MD, chief of endocrinology at Landstuhl Regional Medical Center in Germany, and colleagues evaluated 10 popular thyroid supplements. Of those supplements, which required no prescription, nine of the 10 supplements had detectable levels of thyroid hormones.
If taken at recommended daily doses, those supplements would result in higher levels than recommended by doctors. The result: Side effects such as high heart rate, sweating, and anxiety, according to Stephanie Lee, MD, PhD, director of the thyroid health center at Boston Medical Center.
"Over-the-counter thyroid supplements are not supposed to contain any thyroid hormone," Lee said. "But there's no truth-in-labeling in these supplements."
As a result, people who think that they are getting safe doses of herbs "can become significantly and severely hyperthyroid."
It's dangerous both for people who don't need thyroid medication as well as those who are already taking it, she added.
These supplements have become popular for those hoping for a boost in weight loss. However, Lee contends that less than 10 percent of women actually are hypothyroid and need hormone replacement. In such cases, physicians perform tests and prescribe a carefully calculated amount.
The FDA classifies thyroid drugs as having a narrow therapeutic index.
"That means the amount of medication is so important to have just right, that it requires physicians monitor and measure hormone levels," Lee explained.
Accentuating the danger of these supplements: Added ingredients. Some pills contain iodine, while others are manufactured from seaweed. The result: Contamination with heavy metals, particularly arsenic, Lee said. Seaweed is exposed to these compounds in seawater and when it's dried out, the arsenic and other contaminants can concentrate.
"It's dangerous to take these supplements," Lee said. "You just don't know what's in there."
And the Mayo Clinic warns that although some people use holistic versions of thyroid medication, they are "are available by prescription only and shouldn't be confused with the glandular concentrates sold in natural foods stores. These products aren't regulated by the Food and Drug Administration, and their potency and purity isn't guaranteed."
Bottom line: If you think that you might have thyroid problems, talk with your doctor rather than self-prescribe supplements. Symptoms include weight gain, fatigue, constipation and depression.
Learn more about how your thyroid impacts your weight by clicking here to read Dr. Mehmet Oz's explanation.