June 25, 2024

Open Court


Dayana Yastremska tests positive for mesterolone



News Thursday from Dayana Yastremska, considered one of the rising stars on the WTA Tour and currently ranked No. 29.

The 20-year-old from Ukraine announced on Twitter that she had tested positive for a metabolite of mesterolone on Nov. 24, 2020.

The positive result came in the wake of an out-of-competition test, as her season ended at the Linz tournament in Austria earlier in the month.


ITF announcement follows

Just moments after Yastremska Tweeted out her statement, the ITF issued its press release announcing her provisional suspension, effective immediately.

The provisional suspension is automatic, for that class of prohibited substances.

“Dayana Yastremska has been provisionally suspended under Article 8.3.1(c) of the 2020 Tennis Anti-Doping Programme (the “Programme”), pending determination of the charge against her at a full hearing pursuant to Article 8 of the Programme.

Ms. Yastremska, a 20-year-old player from Ukraine, provided an Out-of-Competition urine sample on 24 November 2020. That sample was sent to the World Anti-Doping Agency (“WADA”) accredited laboratory in Montreal, Canada for analysis, and was found to contain mesterolone metabolite. Mesterolone is a Non-Specified substance, which is prohibited under category S1 of the 2020 WADA Prohibited List (Anabolic Agents), and therefore is also prohibited under the Programme. Positive tests for Non-Specified Substances carry a mandatory Provisional Suspension. 

On 22 December 2020, Ms. Yastremska was charged with an Anti-Doping Rule Violation under Article 2.1 of the Programme (presence of a Prohibited Substance in a Player’s Sample) and was Provisionally Suspended with effect from 7 January 2021. Ms. Yastremska had (and retains) the right to apply to the Chair of the Independent Tribunal convened to hear her case why the Provisional Suspension should not be imposed, but has chosen not to exercise that right to date.”

There have not been many well-known players suspended for doping. Unusually, even though the vast majority of the players who have been suspended are men, two of the high-profile cases involved women.

First there was Maria Sharapova, who ended up serving a 16-month suspension for meldonium that basically derailed the back end of her career. And now Yastremska.

Likely to miss the Australian Open

While it’s not unusual for an athlete to choose not to exercise her right to challenge the provisional suspension, what it typically means is that she is not debating the fact that the substance was found in her system.

While she is understandably not going into more detail, Yastremska’s statement indicates that she believes she inadvertently ingested something that was contaminated with the mesterolone.

These procedures take time – even if there is a quick exoneration (see the Robert Farah case below). So we likely won’t see Yastremska down in Australia.

Yastremska would have been seeded at the Australian Open. And she was set to play doubles with countrywoman Vera Lapko. She also would have been seeded at the 500 tournaments scheduled for the week before the main event. She was not entered in Abu Dhabi this week.

Kaja Juvan of Slovenia would have taken her spot in Melbourne. But Yastremska hasn’t yet withdrawn, so Juvan is the top seed in the qualifying and will have to earn her spot with three victories in Dubai.

Farah precedent could mean quick exoneration

Right about this time a year ago, World No. 1 doubles player Robert Farah also was provisionally suspended after a positive test for boldenone and its metabolite.

(In contrast, Yastremska’s finding was only for a metabolite, not the substance itself).

He was in Adelaide at the ATP Tour event at the time. And, suddenly, he and partner Juan Sebastian Cabal were out of that tournament, and out of the Australian Open. The reason why became clear a few days later as Farah pre-emptively announced the news on Jan. 14.

Contaminated sirloin steak to blame

Farah’s test occurred Oct. 17. He was suspended “with effect” on Jan. 21. And by Feb. 10, the ITF having accepted his explanation for how it was found in his system, he was cleared to return to play.

It was a good story: Farah, who had two clear doping tests earlier in the month (Yastremska says she had a clean test just two weeks prior to this positive test), said he sat down for a meal with his fiancée at his mother’s home in Colombia. The next day, he submitted to an out-of-competition test.

He said that the sirloin steak he ate the night before the test contained residue of “boldenone injected into the cow as a growth promoter prior to slaughter.”

The injection of cattle in Central and South America is fairly widespread, and has been both a warning issued to athletes competing in that part of the world and an explanation for some positive doping tests.

Second blow of 2021 for Yastremska

Yastremska had already had a tough blow even before the 2021 season began.

Upon arrival in Dubai to train for the upcoming campaign, she had tested negative for COVID-19.

But a few days later, she came up positive and had to self-isolate. She also had some fairly severe symptoms, in the context of the tennis players who have caught the virus.

What is mesterolone?

Sold under the brand name Proviron, mesterolone is a synthetic male sex hormone most often prescribed to for an androgen deficiency, and infertility due to low natural hormone levels (also, impotence).


It’s an old-school androgen and anabolic steroid medication that has been around since the 1960s and is used far more by men than women.

Off-label, it’s something that athletes have taken for years to increase athletic performance. Although the studies of its effect on women are less prevalent.

It is often used not by itself, but as an additional medication to enhance the effects of steroid use. “Female athletes who have no difficulties with Proviron obtain good results with 25 mg Proviron/day and 20 mg Nolvadex/day.  In combination with a diet, report an accelerated fat breakdown and continuously harder muscles.”

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