Letrozole metabolite was found in Toon Aert’s out-of-competition urine sample on January 19.

Though the drug may sound unfamiliar to some of us, it’s been in the headlines before.

Jon Jones, an MMA fighter, was caught with Letrozone in his test sample back in 2016. Moving even further back, Canadian wrestler Ilya Manukhov was banned from wrestling for two years when Letrozole was found in his drug test.

Italian tennis star Sara Errani blamed her mom’s tortellini and breast cancer fight for a positive for the same substance.

Why a Breast Cancer Drug?

According to USADA, “Letrozole is in medications used to fight estrogen-dependent breast cancer in women.”

Why would a male athlete use such a drug? USADA lists Letrozole as an aromatase inhibitor, meaning that it blocks an enzyme that is responsible for the conversion of androgens (e.g., testosterone) into estrogens. Take a steroid? You want the testosterone benefits, not higher estrogen.

According to Peter Van Eenoo, head of the anti-doping lab in Ghent, the drug speeds up muscle build and recovery.

“It inhibits the breakdown of testosterone and anabolic steroids.” – Peter Van Eenoo

Eenoo assures us that it’s not an obscure drug. There were 17 cases just in 2020.,

“In 2020 there were 17 cases worldwide, if you know that there were 28 EPO cases, that puts everything in perspective. Letrozole comes back quite often .” – Peter Van Eenoo

Van Eonoo also went on to explain the benefits. “These products are obviously very important in muscle building and promote recovery during periods of intense training or when many competitions follow in close succession,” he said. “Periods of intense training” could accurately describe the pre-Worlds timeframe.

Read the full story here.

Toon Aerts’ Sample History

The sample was taken 10 days before the UCI Cyclo-cross World Championships. If found guilty, his sixth-place finish at the Fayetteville World Championship, his victory in 2022 X2O Trofee Lille – Krawatencross, and third place in the 2022 Gavere Superprestige will be stripped.

According to Sporza, Aerts had no idea what the drug was. He claims that it entered his body unconsciously and he will fight to prove his innocence. Read the full article here.

“The product Letrozole Metabolite was found in my urine sample. A product I had never heard of until yesterday and I don’t know how it got into my body.” – Toon Aerts

He has consulted his team and will be suspending his season until he has more information. Once Aerts’ B sample has been tested, it will shed more light on the situation.

The UCI has not suspended Aerts at this time.

Food Contamination?

Aerts maintains his innocence and awaits his B sample result, and isn’t sure how it got in his body. A toxicologist states it’s been found in “food supplements sold via the Internet.

Contamination of supplements is a common defense, and has been used with mixed success. Denise Betsema shortened her ban by convincing authorities that contaminated supplements were to blame for her positive steroid test. Katie Compton could not avoid such a ban from her positive test for testosterone.

A female boxed successfully blamed sexual transmission on her positive test for Letrozole.

We’ve seen other cyclocrossers, including Masters racers, test positive for steroids and other substances, but hope that the shorter duration of races and smaller budget of our sport in the U.S. keep it the cleanest of the major cycling disciplines.