Shari Bossuyt proclaims innocence, will look to try and prove contamination

Shari Bossuyt gives a press conference after doping positive

Belgian rider Shari Bossuyt gave a press conference this morning where she stated her innocence, despite the pair of in-competition positive tests for Letrozole. Bossuyt tested positive after winning the final stage of Tour de Normandie Féminin on 19th March 2023. An investigation led by AFLD (the French anti-doping authority) is still ongoing.

Talking to the press today, Shari Bossuyt stated that she hasn’t knowingly come into contact with Letrozole and was even the first time that the rider had heard of the substance. In its everyday usage, Letrozole is a breast cancer medicine that works by reducing estrogen levels. It may be used for doping to complement the use of anabolic steroids as it can help lessen some of the side effects, plus raise testosterone levels as well.


“I’ve ended up in an unreal situation, at the moment the procedure is still ongoing and I have to go to the AFLD and explain how the product got into my body. Something that turns out to be extremely difficult today since I have never come into contact with Letrozole and have never consciously used it. In fact, this was the first time I had heard of Letrozole. After some research, it turned out to be the same product that Toon Aerts was confronted with.” 

Fortunately, I am well supported by a team that has been working on it for a year. Hopefully we can quickly clarify to the necessary authorities. And above all that we can prove that we are not cheaters. 

In consultation with the team, I have decided not to race in the coming weeks. Mainly because my head isn’t in it. Everything indicates that we are dealing with a contamination. That is why I would like to appeal to all authorities that we may be dealing with an underlying problem. I will continue to train so that I can compete again soon.”

Shari Bossuyt

The substance Letrozole was also found in a doping control for the cyclocross rider Toon Aerts in early 2022. The Belgian rider has spent his time since that test trying to prove his innocence, believing the substance entered his system through contamination as well. Shari Bossuyt and Toon Aerts share the same manager, Yannick Prévost of ISEA Sports Management, the same agency that looks after stars like Wout van Aert and Fem van Empel.

Another coincidence in both cases is the positive doping controls both taking place in Normandy. For Bossuyt it was during the Tour de Normandie Féminin and for Aerts it was at the Flamanville World Cup cyclocross race. This leads the management team to suspect that local geographical factors are at play, potentially in dairy farming. They won’t rule out the possibility of the riders having local meat or milk for instance and ingesting Letrozole in that way.

Shari Bossuyt
Shari Bossuyt

That defence harks back to the case of Alberto Contador and his positive test for clenbuterol after the 2010 Tour de France. The Spanish rider’s defence was related to beef that had been consumed during the 2nd rest day of that year’s Tour, which had been transported to France from Spain where clenbuterol is used sometimes in livestock farming.

In all of the cases of Bossuyt, Aerts and Contador the levels of substances detected were minute. Bossuyt’s levels are reported as being even lower than the low result from the Toon Aerts case. The rule currently states zero tolerance for any level of Letrozole in a rider’s system, however.


“Due to Toon’s case, we have started to look into the matter and we now know that letrozole metabolite is used in livestock farming to regulate ovulation in cows. That is legal and is not checked by the food inspection, because it does not pose any health risks, but it can cause contamination in milk or meat.

Shari and Toon have nothing to do with each other: she lives in West Flanders, he in the Kempen. She rides on the track and on the road, he is a cyclo-cross rider. They have no common doctor or caregiver. There is nothing, but there will always be people who don’t believe them.”

Yannick Prévost, manager of Shari Bossuyt & Toon Aerts

Whilst the investigation is ongoing, Shari Bossuyt won’t be racing. In her statement, the Belgian says that it’s because her ‘head isn’t in it’, it’s also down to her team Canyon SRAM committing to not selecting her to race whilst the investigation continues, officially making her ‘non-active’. Another knock-on effect is her track cycling partner Lotte Kopcky. The duo are the reigning world champions in the Madison event and were set to be the favourite heading to the 2024 Olympics in Paris.

At this stage, it’s unclear what sanctions, if any, will be involved but it may see a new partner for Kopecky or even non-qualification if previous results are expunged. If a similar punishment to Toon Aerts’ case is meted out, Shari Bossuyt may be looking at a racing ban of 2 years. This would potentially begin from the last active race day, which was April 22nd 2023, a win in the Madison at the Milton World Cup race with Lotte Kopecky. The investigation is ongoing however and no sanctions are in place currently.

Canyon SRAM Shari Bossuyt Letrozole statement June 2023