Bodybuilders Take Breast Cancer Drug

Tamoxifen, an endocrine therapy for women with breast cancer, is found in a supplement marketed to bodybuilders.

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Tamoxifen pillsWIKIMEDIA, NCIFor decades, some bodybuilders who’ve taken steroids to help increase their muscle mass have illegally purchased the breast cancer drug tamoxifen to prevent breast enlargement. But according to new research from Liverpool John Moores University in the U.K., others may simply have bought the dietary supplement Esto Suppress, which was found to contain the drug in three out of four samples tested by the investigators, who published their results last week (February 13) as a letter in the British Medical Journal (BMJ).

“Since the 2000s, a growing number of off-the-shelf ‘food,’ ‘herbal,’ or ‘dietary’ ‘supplements’—aimed at gym goers and people wanting to lose weight or enhance their sex lives—have contained pharmacologically active substances,” the authors wrote. “Most users will be unaware that they are taking these substances.”

The amount of tamoxifen varied by sample, with one sample containing 3.8 mg per pill. The suggested dose of Esto Suppress is two pills per day; when the drug is prescribed for early-stage breast cancer, patients typically take 20 mg a day. The researchers noted, however, that their samples were purchased two years ago, and it is not known whether the supplement still contains tamoxifen.

“This research highlights the need for consumers to be aware when choosing their sports supplements,” ...

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Meet the Author

  • Jef Akst

    Jef Akst was managing editor of The Scientist, where she started as an intern in 2009 after receiving a master’s degree from Indiana University in April 2009 studying the mating behavior of seahorses.
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