Formestane, 4-hydroxytestosterone and 6a-hydroxyandrostenedione
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Racing Victoria (RV) advises that it has issued charges against six licensed trainers who each presented a horse to race with formestane, 4-hydroxytestosterone and 6a-hydroxyandrostenedione within their system which is prohibited under the Australian Rules of Racing (AR).
The charges relate to samples collected on racedays between 14 April 2025 and 22 November 2025. Investigations into the samples have continued in the period since their collection with RV Stewards examining stable environments, products and practices before determining to proceed with presentation charges against each trainer pursuant to AR 240(2).
The trainers have not been charged with administering a prohibited substance, be that inadvertently or deliberately. A presentation charge means that a prohibited substance is detected in a sample taken from a horse brought to a racetrack. The circumstances that led to the detection of a prohibited substance do not need to be established for a presentation charge.
4-hydroxytestosterone and 6a-hydroxyandrostenedione are anabolic androgenic steroids, whilst formestane is an aromatase inhibitor and anti-estrogenic substance.
Pursuant to AR 248(4) a horse that presents with anabolic androgenic steroids in its system must be stood down from competing for 12 months. That mandatory ruling was enacted for each of the six horses from the date that their sample was collected.
The Australian Rules of Racing are at the heart of the sport and all decision making by RV Stewards. When substances are strictly prohibited at all times under those Rules, RV Stewards cannot shy away from their responsibility to apply them as written and uphold the integrity of the sport.
Including the six announced today, a total of 13 thoroughbred racehorses from 13 training stables were presented to race in Victoria between February 2023 and November 2025 with formestane, 4-hydroxytestosterone and 6a-hydroxyandrostenedione detected in their system.
There have been no detections confirmed in thoroughbreds presented on course to race in Victoria in the eight months since November 2025 and there are no further cases currently under investigation.
The Victorian-based Racing Analytical Services Limited (RASL) – the only racing laboratory in Australia accredited with the International Federation of Horseracing Authorities (IFHA) – detected the prohibited substances in urine samples taken on raceday. Testing by other approved racing laboratories confirmed the presence of the prohibited substances in the samples.
RASL has been screening for the presence of formestane, 4-hydroxytestosterone and 6a-hydroxyandrostenedione since 2017. There were no detections of these prohibited substances in any samples collected in the six years prior to 2023.
RASL first detected the three substances in February 2023 in a urine sample from a Chilean racehorse whose connections admitted to an oral administration of a product containing dehydroepiandrosterone (DHEA) among other substances. The only reported finding of formestane in an equine sample prior to 2023 was a detection by the Hong Kong Jockey Club in an Indian racehorse in 2011.
RASL has stated in the Victorian Racing Tribunal (VRT) and during RV’s investigations that there has been no change to any of their equipment, procedures, methodology, or sensitivity since 2017 that may have helped to explain the cluster of 24 positive samples it detected from 2023 to 2025 in thoroughbred and harness racing horses across Victoria, South Australia, Tasmania and Chile.
Since 2017, RASL has analysed over 40,000 equine urine samples across the different racing codes and jurisdictions with formestane, 4-hydroxytestosterone and 6a-hydroxyandrostenedione detected in just 0.06% of those samples.
Since the first detection in Victoria in February 2023, RV has been engaging with experts locally and internationally to better understand formestane, 4-hydroxytestosterone, 6a-hydroxyandrostenedione and DHEA to help its investigations into the samples collected with prohibited substances within.
It was established that research conducted to date on the substances was limited in its nature due to the scope of work undertaken and/or the absence of an accredited test to quantify exact levels when found to be present.
Accordingly, RV commissioned RASL in May of this year to undertake a global research study into more than 15 target compounds including formestane, 4-hydroxytestosterone, 6a-hydroxyandrostenedione and DHEA. That research study will:
Develop, validate and accredit a sensitive analytical method to detect and quantify the presence of formestane and related substances in equine urine samples;
Investigate any potential correlation of formestane prevalence to DHEA; and
Propose suitable quantitative criteria for reporting the presence of formestane in equine urine samples.
Work on the study is underway and will take at least 12 months to conclude. It will see Australian and international racing laboratories participate in a study involving a minimum of 1,000 equine urine samples representative of all genders. It will also incorporate a study of samples administered with DHEA.
Should the research study RV has commissioned determine that formestane and its metabolites are endogenous at low levels in racehorses then that would most likely require a change to the Australian Rules of Racing and a threshold to be implemented if attainable.
If that occurs in the future, it’s important to note that the Australian Rules of Racing are generally not retrospective. The Rules at the time an offence occurred are generally applied so it would unlikely change the outcome for any samples collected prior to that time.
Cases involving six of the 13 Victorian training stables have now concluded at the VRT, an independent panel with Judicial Officers appointed by the State Government.
Each of the six trainers/training partnerships pleaded guilty to breaching AR240(2) and were fined by the VRT for presenting their horse on raceday with a prohibited substance in its system. Those cases have now established a precedent for future cases in terms of what is an appropriate penalty.
Whilst each case is treated on its merits based upon the information and facts at the time, RV Stewards are proceeding with other cases on the same basis and using the VRT precedent until such time as there is verified information or evidence to the contrary, or the VRT determines an alternative precedent.
Following the 2025 removal of AR240(2) from the Serious Offence List with effect from 1 July 2025, the four trainers charged today whose positive samples were collected after this date will have their charges heard by RV Stewards. It is hoped this will occur in the next four to six weeks.
The two trainers whose positive samples were collected prior to 1 July 2025 have had their charges referred to the VRT as required under the Rules at the time. They will be heard by the VRT on a date to be fixed.
Click here to view the Stewards Reports for trainers Matthew Brown, Adam Chambers, Nathan Dunn, Lee & Shannon Hope, Lloyd Kennewell and Paul Preusker.