Bodybuilders Take Breast Cancer Drug

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

Written byJef Akst
| 1 min read

Register for free to listen to this article
Listen with Speechify
0:00
1:00
Share

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,” ...

Interested in reading more?

Become a Member of

The Scientist Logo
Receive full access to more than 35 years of archives, as well as TS Digest, digital editions of The Scientist, feature stories, and much more!
Already a member? Login Here

Related Topics

Meet the Author

  • Jef (an unusual nickname for Jennifer) got her master’s degree from Indiana University in April 2009 studying the mating behavior of seahorses. After four years of diving off the Gulf Coast of Tampa and performing behavioral experiments at the Tennessee Aquarium in Chattanooga, she left research to pursue a career in science writing. As The Scientist's managing editor, Jef edited features and oversaw the production of the TS Digest and quarterly print magazine. In 2022, her feature on uterus transplantation earned first place in the trade category of the Awards for Excellence in Health Care Journalism. She is a member of the National Association of Science Writers.

    View Full Profile
Share
December digest cover image of a wooden sculpture comprised of multiple wooden neurons that form a seahorse.
December 2025, Issue 1

Wooden Neurons: An Artistic Vision of the Brain

A neurobiologist, who loves the morphology of cells, turns these shapes into works of art made from wood.

View this Issue
Stacks of cell culture dishes, plates, and flasks with pink cell culture medium on a white background.

Driving Innovation with Cell Culture Essentials

Merck
Stacks of cell culture dishes, plates, and flasks with pink cell culture medium on a white background.

Driving Innovation with Cell Culture Essentials

MilliporeSigma purple logo
Abstract wireframe sphere with colorful dots and connecting lines representing the complex cellular and molecular interactions within the tumor microenvironment.

Exploring the Inflammatory Tumor Microenvironment 

Cellecta logo
An image of a DNA sequencing spectrum with a radial blur filter applied.

A Comprehensive Guide to Next-Generation Sequencing

Integra Logo

Products

brandtech logo

BRANDTECH® Scientific Announces Strategic Partnership with Copia Scientific to Strengthen Sales and Service of the BRAND® Liquid Handling Station (LHS) 

Top Innovations 2026 Contest Image

Enter Our 2026 Top Innovations Contest

Biotium Logo

Biotium Expands Tyramide Signal Amplification Portfolio with Brighter and More Stable Dyes for Enhanced Spatial Imaging

Labvantage Logo

LabVantage Solutions Awarded $22.3 Million U.S Customs and Border Protection Contract to Deliver Next-Generation Forensic LIMS