Experimental Drug Ostarine Plagues Elite Sports

Banned performance enhancer complicates doping rules and athletes' careers

Published on Feb. 8, 2026

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A drug designed to help patients build muscle, called ostarine, has become a persistent problem in elite sports as a banned performance enhancer. Despite never being approved for human use, ostarine has spread through the supplement market and led to a wave of positive drug tests, often due to accidental exposure through contaminated products. This has collided with anti-doping agencies' zero-tolerance policies, resulting in suspensions and derailed careers for some athletes.

Why it matters

Ostarine's potency in tiny doses, tendency to contaminate other supplements, and ability to be transferred through sweat or sexual contact has created a challenging situation for anti-doping officials. The unintentional positive tests have highlighted the complexities of enforcing doping rules around an unapproved drug that was originally intended for medical purposes.

The details

Ostarine was originally developed by pharmacologist James Dalton in 2000 as part of a class of drugs called SARMs, or selective androgen receptor modulators, which aim to provide the muscle- and bone-building benefits of testosterone and steroids without the masculinizing side effects. Before the drug was ever approved for medical use, it started appearing in elite athletes' urine samples, leading to it being banned by the World Anti-Doping Agency. Overseas labs began producing ostarine, and it spread to various sports as a performance enhancer, despite never receiving regulatory approval.

  • In 2000, pharmacologist James Dalton was testing the compound that would later be called ostarine.
  • The World Anti-Doping Agency banned ostarine after it started appearing in elite athletes' urine samples.
  • In 2024, American bobsledder Sydney Milani tested positive for a trace amount of ostarine, which investigators concluded she likely ingested unintentionally through a contaminated energy drink.

The players

James Dalton

A pharmacologist who was testing the compound that would later be called ostarine in 2000, with the goal of capturing the muscle- and bone-building benefits of testosterone and steroids without the masculinizing side effects.

Sydney Milani

An American bobsledder who tested positive for a trace amount of ostarine in 2024, which investigators concluded she likely ingested unintentionally through a contaminated energy drink.

World Anti-Doping Agency

The organization that banned ostarine after it started appearing in elite athletes' urine samples.

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What’s next

A former collaborator of James Dalton is still pursuing ostarine, now under the name enobosarm, as a companion to GLP-1 weight-loss drugs to preserve muscle.

The takeaway

The case of ostarine highlights the challenges anti-doping agencies face in enforcing rules around an unapproved drug that was originally intended for medical purposes but has become a persistent problem in elite sports as a banned performance enhancer, often leading to unintentional positive tests.