Any substance, which increases or improves work production, can be described as ergogenic. In the case of a human or animal athlete such improvements may result in increased speed, endurance and strength.
Such nutritional ergogenic products function in one of the following ways;

• Affect the nervous system by recruiting muscle fibres and affecting co-ordination
  
• Delay or reduce the effects of end product build up, such as heat or lactic acid
  
• Act as a supplementary fuel source for energy production
  
• Affect the flux of fuels through energetic metabolic pathways