MSM FEI Ruling Info

MSM FEI Ruling Info;
Is MSM a prohibited substance under the racing and FEI regulations?

MSM or Methylsulfonylmethane is added to a lot of horse NZ feed supplements. Which is logical as there are several claims MSM has helped ease a number of ailments in horses young & old.

Please read the renewed warning for supplements in horses, humans.

The advice comes after the revision of the World Anti-Doping Code (WADA) 2015, which is effective from January 1. The FEI General Assembly has significantly amended its equine and human anti-doping rules have been significantly. Click HERE for more info.

In short; you are as a competitor, responsible for any feed supplement you give to your horse that it is within the regulations of the FEI or Racing Industry.

MSM is know under a variety of names eg;

  • methyl sulfone
  • methylsulfonylmethane
  • sulfonylbismethane
  • and the most common, methanesulfonylmethane.

Putting them through the FEI database we get a result on Dimethyl Suphone (Dimethyl Sulfone).

FEI Classification:Prohibited Substance Controlled Medication Definition:Solvent Information: It is used in the treatment and prevention of osteoarthritis, seasonal allergic rhinitis, and interstitial cystitis.


  • With all medications, a clinical judgment is essential to ensure that the welfare of the horse is never compromised by administering a drug at a time too close to an event such that it may mask symptoms and could aggravate a clinical condition. Horses with loco-motor problems in particular must always be provided with adequate rest. Common Trade Names: NatraFlex, Neosulfur, ProFLEX 750 The trade names used may be different in your country therefore it is imperative you always use the database to check for active substances rather than trade names.

Link to FEI page, click here

When we look up the product NatraFlex the FEI is referring to, as an example the ingredients are;
NatraFlex Pure “Maximum benefit for flexible healthy joints” A mix of natural Glucosamine and MSM that enhance each other’s beneficial properties. This combination effectively supports joints,muscles and connective tissue. Glucosamine is a building block of cartilage and adds to levels already present in the body. Also helps joint wear and tear and degenerative disease. MSM nutritionally aids repair of damaged tissue and helps the creation of new cells, collagens and connective tissues.

CONTENTS: No fillers, just pure Glucosamine mixed with naturally extracted MSM.
Link to example product click here

Does that mean we cannot feed MSM to our horses?
Our advice is to withhold 4 days before competition any supplement containing any form of MSM,

(see above for most used names) and to check with your own veterinarian, better safe than sorry.

To order MSM for horses click here

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