Doping Dilemma: What Happened with Swiatek and Sinner?

2024 was a wild year for tennis in terms of substance abuse allegations. Not just one but both world singles #1 players, Iga Swiatek and Jannik Sinner, received heat for testing positively for prohibited, performance-enhancing drugs. Doping in tennis is a relatively new phenomenon – two of the cases you may remember the best were Maria Sharapova (2016) and Simona Halep (2022). In this blog post, we’ll cover both cases of recent doping and pose the question - are Jannik and Iga’s punishments justified?

One reason for the increased attention on this topic could be that in recent years, the game has gotten exponentially more intense – if we take a look at the US Open 2024, many players retired mid-match, including Dimitrov, Purcell, Djere, and Sakkari. Djokovic himself ended up with an awful-looking hamstring injury after crashing out vs. Popyrin:

Tweet sent out by Djokovic, defending his injury post-US Open 2024

The increasing difficulty of tennis at the pro level can be attributed to many factors, including climate change (hotter temperatures outdoors), improved access to the sport (more competition), and advancements in equipment + training. Nevertheless, players must continue to rely only on proper conditioning to overcome the brutal play that is sometimes required to beat their opponent. If not, WADA (the World Anti-Doping Association) will be waiting just around the corner. However, sometimes, “doping” can be an accident, or rather, a function of a bit of carelessness.

Iga’s Doping Case

Trimetazidine (TMZ) is a drug that’s used to treat angina caused by coronary artery disease. Angina occurs when your heart isn’t getting enough oxygen, in this case, due to a build-up of plaque in your arteries. TMZ works by inhibiting an enzyme that is involved in breaking down fat for energy. If the heart muscles can’t use fat for energy, they must use glucose, or sugar, which is a much more efficient source of energy. 

TMZ's molecular structure

Now imagine taking this drug, but without heart problems – improved heart mechanics means more blood flow, which means your cells have more oxygen to use to respirate and create a form of energy called adenosine triphosphate – also, ironically, known as ATP! In a very simplified sense, it allows you to take one less breath per point than you otherwise would have needed to – which adds up over the course of a match. 

Fun fact: TMZ is not approved in the US, due to concerns about adverse effects, including Parkinsonian symptoms. In other words, there are alternative drugs that can do the same thing but without the same dangers. 

TMZ is exactly what Iga tested positive for on August 12, 2024. The International Tennis Integrity Agency (ITIA) handed her a mandatory provisional sentence on September 12, which she then appealed on the 22nd. This was when she learned the context of the contamination – a non-prescription sleep medication from Poland that she had been using for jet lag. Unfortunately, she did not possess a Therapeutic Use Exemption (TUE), which would have prevented this situation from growing.

However, the ITIA appeared to have recognized that this was a violation at the “lowest end of the scale,” as they lifted her suspension on October 4. Following an additional one-month sanction, Swiatek returned to the WTA Finals on November 3. On January 20, WADA confirmed they would not be appealing the case - Iga had been officially vindicated. What a crazy 6 months it must have been for her! 

An aside - you might be wondering, why was there TMZ in the melatonin? It could have been as simple as the Polish manufacturing facility producing the two drugs on the same line creating cross-contamination.

Jannik’s Doping Case

Clostebol is a synthetic anabolic-androgenic steroid (AAS) that is a derivative of testosterone. Essentially, to create clostebol, scientists took testosterone, enhanced the anabolic properties (for tissue building), and reduced the androgenic properties (for sexual health). The drug binds to androgen receptors, improving nitrogen reception (better protein synthesis) and red blood cell production (better oxygen delivery). It can be given through the skin, making its way through the epidermis and dermis to the hypodermis, where it diffuses for an extended period. 

Trofodermin spray (contains Clostebol)

On March 10 and 18, 2024, Jannik tested positive for less than a billionth of a gram in his system. The explanation? His physiotherapist had been applying Trofodermin spray to himself (contains clostebol) which was purchased by his fitness coach over-the-counter in Italy to treat a small wound. 

Sinner’s punishment was quite harsh – he lost the $325k and the 400 points he accumulated at Indian Wells, where he played a great match against Alcaraz:

Given that it was his staff and not him that administered the drug, this made things much easier on Sinner. Furthermore, experts weighed in on the minimal traces of the substance that were reported:

"Even if the administration had been intentional, the minute amounts likely to have been administered would not have had any relevant doping, or performance enhancing, effect upon the player."

- Professor David Cowan, a member of the ITIA tribunal for its final ruling on the case

Sinner responded by firing both members of his staff – a mature decision on his part. On September 26, WADA appealed ITIA’s August 15 decision of “no fault or negligence.” Initially, there was to be a closed-door hearing in April 2025, but it was announced in mid-February 2025 that Sinner had agreed to a 3-month ban. Given that WADA was looking for a 1-2 year ban, Jannik probably thought the punishment was too long and decided to settle for a shorter ban period. The negotiation was a win-win; Sinner gets to return for the summer Grand Slams (and has little points to defend in the meantime; it is highly unlikely he loses the top spot), while WADA can chalk this up as a victory. 

At the end of the day, as the expert noted, no matter how much Trofodermin you’re using for recovery, it’s not going to drastically improve your play. Jannik and Iga are major draws for tennis, so suspending them could be a risky decision, especially with the growing competition from other racket sports like pickleball and padel. Similar situation with Iga on the WTA side. '

Do you think they’re actually guilty and should be punished more harshly? Tell us why in the comments! 

Works Cited

Michaels, J. (n.d.). Everything to know about the sinner and Swiatek doping cases. ESPN. https://www.espn.com/tennis/story/_/id/43363975/tennis-australian-open-jannik-sinner-iga-swiatek-doping-cases-faq-questions-next

What is the mechanism of Clostebol acetate?. Synapse. (n.d.). https://synapse.patsnap.com/article/what-is-the-mechanism-of-clostebol-acetate

Zaouali, M. (2015, April 9). Melatonin and trimetazidine cocktail for increasing fatty liver graft preservation: AMPK involvement in endoplasmic reticulum stress and autophagy modulation. ATC Abstracts. https://atcmeetingabstracts.com/abstract/melatonin-and-trimetazidine-cocktail-for-increasing-fatty-liver-graft-preservation-ampk-involvement-in-endoplasmic-reticulum-stress-and-autophagy-modulation/