Posted 20th September 2017
Proposed additions to the FEI Prohibited substances list in 2018
The FEI will shortly publish its list of prohibited substances for 2018. In June, when the provisional list was published, concerns were raised regarding the naming of MSM as a banned substance.
The proposed amendment for 2018 proposed a reclassification of Dimethyl Sulphone (DMS), from “Banned Substance” to “Banned Substance and Specified Substance”. The accompanying guidance stated “Dimethyl sulphone is often referred to as MSM”; this was the first mention of MSM in relation to prohibited substances, even though it had been on the list for some time under its little used alias of Dimethyl Sulphone
Given that MSM use is commonplace in equine diets, and feed rates can be up to 20g per day, and there have been no positives in the time that DMS has been listed as a banned substance, this suggested that there has always been a generous screening limit.
The FEI has since confirmed this – they use a high Harmonised Performance Level, which is an agreed reporting level between the different FEI testing laboratories, for monitoring DMS/MSM in blood and urine samples. The FEI’s principal reason for listing DMS/MSM appears to be that MSM is also the major metabolite of a compound known as DMSO, that is also a banned substance, and which is used in some therapeutic preparations, such that a very high level of MSM could indicate inappropriate use of DMSO.
The FEI has stated that it would be highly unlikely that the normal use of MSM would cause a positive MSM finding, which means that riders can continue to use MSM-containing products in their competition horse diets, such as Equilibrium FlexiMunch