Tyson Gay ban – what is oxilofrine?

US sprinter Tyson Gay has admitted that he has been tested positive for a banned substance and has pulled out of the Athletics World Championships in Moscow to be held in August 2013. – AFP

Oxilofrine is the prescription name for methylsynephrine, hydroxyephrine and oxyephrine. It is not widely used in the UK and is not a licensed drug in the US.

Some companies use oxilofrine, in the form of synephrine, in “sports nutritional supplements” as it is thought to allow people to enhance fat-burning and lose weight.