The New Way Athletes Are Beating Drug Tests

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by Cy Willson​

An Update to the Doping Arms Race​

When it comes to doping in sports, some scientists are trying to catch the cheaters; others are helping them cheat. Here’s the latest trickery.

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In sports, athletes looking for a chemical advantage are pitted against the anti-doping agencies tasked with catching them. The use of androgens is, aside from amphetamines, one of the oldest forms of modern doping.

Carbon isotope ratio analysis (GC-IRMS) was once thought to be the greatest weapon against doping. However, underground labs are now producing nandrolone and testosterone with carbon isotope ratios in the same range as those found in their endogenous or naturally occurring counterparts.

The Cat and the Mouse​

Analytical chemistry methods have evolved over the years. Athletes using androgens are more likely to be caught. However, the agencies responsible for keeping androgens out of sports publish their methodology, so it’s always only a matter of time before someone exploits those methods.

For instance, knowing that endogenous testosterone (T) and its epimer, epitestosterone (E), are produced within a fairly narrow range in humans, allows for a determination for further testing for possible exogenous T if the T/E ratio is beyond 4. However, some of the more clever individuals began administering E along with their T to keep a more believable ratio that wouldn’t be flagged for additional testing.

What’s the Best Way to Catch a Cheater?​

For years now, it’s been gas chromatography coupled to isotope ratio mass spectrometry, or GC-IRMS. This method determines whether androgens occur from endogenous (natural or internal) production or exogenous (outside) production.

GC-IRMS is used to measure the carbon isotope ratio of testosterone and nandrolone based on the notion that if these substances are produced endogenously, they’ll have a C13/C12 ratio. That’s different than those produced synthetically. This is because the source for most synthetically produced steroids today is phytosterols from soy.

Before we go any further, a quick review.

If you remember from high school biology, plants obtain carbon dioxide (CO2) from the air and use it to make carbohydrates as part of photosynthesis. The carbon in this CO2 consists of carbon-12 and carbon-13, which are stable isotopes. Plants are classified as belonging to C3 (using a pathway resulting in a three-carbon atom molecule), C4 (using a pathway resulting in a four-carbon atom molecule), or crassulacean acid metabolism or CAM (plants using both C3 and C4 pathways).

Due to a large isotope effect during photosynthesis, C3 plants such as soy produce significant C13 discrimination, resulting in reduced C13 content as compared to C4 plants yielding an isotope ratio that’s clearly distinct from endogenously produced androgens. These are produced from a diet consisting of both C3 and C4 plants.



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CAM Plants: How the Unnatural Seem Natural​

Some clever individuals realized that instead of using soy phytosterols for raw material to synthesize testosterone and nandrolone, using CAM plants, (which use both C3 and C4 pathways) yields a carbon isotope ratio more consistent with that seen in a human producing the androgen naturally.

Some scientists hypothesize that agave and sapogenins within the plant may be the source material in question (1). Sapogenins from yams were originally used for steroid synthesis decades ago before cheaper methods using soy were discovered. While these alternative methods are more expensive than soy-derived raw materials, those looking to cheat the system find the price worth it.

A recently published study found the vast majority of samples from individuals flagged for drug use showed use of nandrolone with an endogenous carbon isotope ratio profile (2). Nonetheless, the authors demonstrated that other methods (like nandrolone metabolite levels and endogenous reference compounds) would still have been able to catch those individuals, or at least flag them for more investigation.

Nonetheless, if someone put a lot of time and effort into it and the timing was right, it seems possible they could use nandrolone or testosterone while avoiding detection, even with GC-IRMS.

In short, the cat-and-mouse game continues, and the mice are getting smarter.