What is clomifene? Conor Benn returns ‘adverse’ drugs test ahead of Chris Eubank Jr fight

The highly-anticipated fight between Chris Eubank Jr and Conor Benn was thrown into doubt on Wednesday when confirmation arrived that the latter had returned an ‘adverse’ drug test result.

A joint-statement from promoters Matchroom Boxing and Wasserman confirmed Benn returned a result with ‘trace amounts of a fertility drug’.

Wasserman promoter Kalle Sauerland confirmed the substance was clomifene while also revealing that “a trace finding of a female fertility drug” was found in Benn’s result “at the end of August or start of September” during the Vada testing scheme as agreed during negotiations for the fight.

Sauerland also told Talksport: “It’s a non-performance enhancing drug, but it can raise testosterone.”

But despite the news – and the British Boxing Board of Control ‘prohibiting’ the fight – Eubank Jr “wishes to proceed” with Saturday’s catchweight main event at London’s O2 Arena. Here is everything we know about the drug involved:

The drug is recognised as “a female fertility drug” and is a type of medication used by women who do not ovulate, including those with polycystic ovary syndrome.

Clomifene is a selective estrogen receptor modulatorunder (SERM) and can be found on Wada's Prohibited Substance List, which is sourced by the Ukad website, it is located under the S4 sub-section "Hormone and Metabolic modulators" as an anti-estrogenic substance.

While another anti-doping agency Usada detail how clomifene can result in increased muscle mass.

The US governing body also outlines the potential side effects, including risk of negative cardiovascular events, liver damage, and gastrointestinal discomfort. However, the side effects in men are yet to be determined through long-term studies.

Benn and Eubank Jr are set to face each other in a 157lbs catchweight contest, which will see the latter cut three pounds more than usual while Benn moves up two weight classes.

Wasserman’s Kalle Sauerland, who represents Eubank Jr, told Talksport on Wednesday: “The instant reaction is, ‘The fight is off...’ [but] the fight on Saturday is on.

“You have to look into what it is; a banned substance is a banned substance, end of. The scenario around it... how it could come to that, why are the other tests not positive? There’s been a big mistake here.

“Has it been done as a PED [performance-enhancing drug]? No – that’s the medical opinions we have had.”

Benn and Eubank Jr’s fathers engaged in one of the most storied rivalries in British boxing history, with Chris Eubank stopping Benn in the ninth round of their first clash, in 1990, before they fought to a split draw in 1993 – almost 29 years to the day before this Saturday’s scheduled bout.