Springbok Asenathi Ntlabakanye tests positive for 'non-performance enhancing' banned substance

John Maytham, standing in for CapeTalk's Lester Kiewit, speaks to Sports Scientist Dr Ross Tucker.

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Springbok prop Asenathi Ntlabakanye (26) has tested positive for a banned substance in a random test conducted by the South African Institute for Drug Free Sport.

SA Rugby insists the substance is 'non-performance enhancing' and was taken under medical supervision for legitimate reasons.

This means Ntlabakanye will not travel with the Springboks to New Zealand for the next two rounds of the Rugby Championship.

Ntlabakanye has disputed that he has committed any anti-doping violations, and according to a statement released by the Springboks, he was 'transparent in his declarations, acted in good faith and at all times followed the medical due process as prescribed by the industry'.

The South African rugby union also specified that he 'relied on the relevant professional medical advice', and at no time did he seek to 'obtain an unfair advantage', nor take any medical substance 'without prior medical authorisation'.

The non-performance enhancing substance for which he has tested positive was reportedly prescribed by a specialist physician early in 2025 for medical reasons and then taken with the approval and the supervision of a medical doctor specifically appointed to manage the medical affairs of professional rugby players.

The case raises questions about how anti-doping rules are applied and what it means for players and the game.

"There's actually a specific group of substances on that prohibited list that's known not to be directly performance-enhancing... they're on that list as 'banned' because they might have the ability to mask other doping. The most immediate one that comes to mind is a substance called a diuretic... these are substances that dilute the urine and help hide the presence of banned substances, and that's why they're on the banned substances list. It could be that he has been prescribed a drug like that... which is on the banned list, but they are also correct in saying it's not performance enhancing... whether or not that plays well in his [Asenathi Ntlabakanye] defence is another question."

- Doctor Ross Tucker, Sport Scientist

Tucker explains what the most likely argument could be from past arbitration cases of the same nature.

"If, as they're saying, this medicine was prescribed to him by a specialist and then it was approved by the doctor's who works with the players in the rugby environment... you'd be saying that the player who's not medically qualified needs to challenge and almost override medical advice they're given in order to ensure they don't dope... he will say: 'I'm just a rugby player, I take medical advice from two different people, if those two people have said I can use it, who am I to contradict them?' When the arbitration happens, he will stand behind that and say: 'Look, I'm not contesting that the substance was not in my body, but I didn't put it there for performance enhancement and therefore, I shouldn't serve a ban.'"

- Doctor Ross Tucker, Sport Scientist

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