The FEI would like to warn the equestrian community regarding synephrine, a substance listed as a Banned Substance (Specified Substance*) on the Equine Prohibited Substances List.

Note: Synephrine is also a banned substance under United States Equestrian Federation Drugs and Medications rules

A high number of samples taken from horses under the Equine Anti-Doping and Controlled Medication Programme have tested positive for the substance. Although investigations into the sources of the positive cases are still ongoing, the FEI would like to warn stakeholders of synephrine which may be found in the horse’s environment and advise on measures that can be taken to prevent a positive finding.

Synephrine is a stimulant which can cause vasoconstriction, an increased heart rate and is used as a weight loss aid.

In certain parts of the world, synephrine can be found in plants such as common rush (Juncus usitatus), Mullumbimby couch (Cyperus brevifolus) and the leaves of citrus trees (e.g. mandarin, orange and lemon). Synephrine has also been detected in Teff grass hay in some countries.

It can also be found as an ingredient of herbal and nutritional supplements, and commonly found in the peel extract of bitter orange (also known as Seville orange) which is used as a flavouring agent.

Measures that can be taken to prevent positive findings include using reputable suppliers of hay, feed and supplements, checking the horse’s environment for plants containing synephrine, and ensuring that any personnel taking supplements or other products containing synephrine wash their hands thoroughly after coming into contact with the substance. Additionally, it is recommended that samples are kept of batches of hay, feed and supplements given to competition horses to enable a thorough investigation to take place should the horse test positive for synephrine.

Further information concerning contamination prevention can be found here.

The FEI urges stakeholders to be vigilant of possible sources of synephrine in the horse’s environment and implement management practices to prevent contamination or inadvertent ingestion of the substance.

* Prohibited Substances that are identified as Specified Substances should not in any way be considered less important or less dangerous than other Prohibited Substances. Rather, they are simply substances which are more likely to have been ingested by Horses for a purpose other than the enhancement of sport performance, for example, through a contaminated food substance.