Australia’s Altrenogest (Regu-Mate) Debate

Australia’s Altrenogest (Regu-Mate) Debate

Australia’s Altrenogest (Regu-Mate) Debate

Regu-Mate is the hot topic in Australian racing today, the debate gathered steam after a July FDA warning in the USA that was pointed towards the safe usage of the drug in regards to the human handlers, not really about the impact or performance enhancing results. But, on the eve of the Spring Racing Season the plans of owners and trainers who race mares are up in the air, even for the greats like Winx.

Altrenogest, which is a hormone in regu-mate, a drug given to control oestrogen in fillies and mares to keep them from coming into season, to help broodmares retain foals in difficult pregnancies and to help keep horses calm.

The U.S. Food and Drug Administration is alerting veterinary medical professionals, as well as those who work with horses and pigs, that a synthetic progesterone product commonly used in these animals may cause reproductive system disorders and other adverse effects in people who become exposed to the drug.


Women who are or suspect they are pregnant.
Anyone with thrombophlebitis or thromboembolic disorders or with a history of these events.
Anyone with cerebral-vascular or coronary-artery disease.
Women with known or suspected carcinoma of the breast.
People with known or suspected estrogen-dependent neoplasia.
Women with undiagnosed [unexplained] vaginal bleeding.
People with benign or malignant tumors which developed during the use of oral contraceptives or other estrogen-containing products.
Anyone with liver dysfunction or disease.

Other research in the USA has shown there is no performance enhancing side effect of the drug.

Effect of prolonged use of altrenogest on behaviour in mares.


Oral administration of altrenogest for oestrus suppression in competition horses is believed to be widespread in some equestrian disciplines, and can be administered continuously for several months during a competition season. To examine whether altrenogest has any anabolic or other potential performance enhancing properties that may give a horse an unfair advantage, we examined the effect of oral altrenogest (0.044 mg/kg), given daily for a period of eight weeks, on social hierarchy, activity budget, body-mass and body condition score of 12 sedentary mares. It was concluded that prolonged oral administration of altrenogest at recommended dose rate to sedentary mares had no effect on dominance hierarchies, body-mass or condition score.

No More Mares in the Spring Carnival

Yes, that is exactly what some say a ban on Altrenogest could mean, mares come in to season every spring, and that cycle can lead to a wide variation in the athletic performance of some mares that are related to the estrous cycle have been observed.

Estrus‐related behavioral or performance problems include difficulties during riding or training, back or flank pain, aggressiveness to other horses or people, frequent urination, colic signs and undesirable estrous behavior during competition or training. Synthetic progestins, including altrenogest (Regu‐Mate), are used to modify undesirable estrus‐related behavior or poor performance in mares.

Simply put there would be virtually no mares racing in the Spring in Australia.

Another issue is that NSW and Victoria could end up with different rules, a disaster for Australian racing, there really is no place for infighting between the states.

But in Australia the debate is on the strict rules around the use of steroids, namely trenbolone and or trendion.

As of now Victoria has stuck to the ruling that trainers and veterinarians are advised to immediately stop the use of products that contain altrenogest. Racing Victoria’s Integrity Services Department has been made aware that products containing altrenogest may contain levels of trenbolone and or trendione, which are banned substances with extended detection times.

“Since that time, RV has commissioned further analytical work and have liased with manufacturers to seek clarity on how trenbolone and/or trendione came to be present in these products.

“RV have also been in contact with several leading trainers and veterinarians to gain further understanding of the impact on fillies and mares of they are not to be administered altrenogest.

“At this stage, RV has not reached a final position on the use of products containing altrenogest and will update industry participants once a decision has been made.”

Racing NSW Chief Executive Mr Peter V’landys AM said:

“The use of altrenogest products in fillies and mares has been permitted in racing for many years. Its use helps alleviate work, health and safety issues as well as ensuring that all horses race consistently. Given the insignificant trace levels found in these oral substances and having regard to advanced testing equipment used by the Australian Racing Forensic Laboratory and the fact that it’s so miniscule it has no effect on the horses performance, the Board has introduced the local rule 44A to safeguard the NSW racing industry by allowing fillies and mares to continue to be administered oral altrenogest.”

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S. Jack Heffernan Ph.D. Funds Manager at HEFFX holds a Ph.D. in Economics and brings with him over 25 years of trading experience in Asia and hands on experience in Venture Capital, he has been involved in several start ups that have seen market capitalization over $500m and 1 that reach a peak market cap of $15b. He has managed and overseen start ups in Mining, Shipping, Technology and Financial Services.

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