Professor [Wayne McLaughlin], a biochemist, responded saying that while the stimulant was of a higher concentration in the athlete s sample - 720 nanograms per millilitre - it would be difficult to say since the effects of the stimulant on an athlete vary depending on the individual. He did acknowledge, however, that the stimulant could have had a direct effect on the athlete s neurotransmitters, which could mean that the athlete may have been aware of the effects on his body.