GCSE Biology

boost bodily functions , including heart rate and brain activity

cocaine

they stimulate muscle growth and can allow athletes to train harder and recover more quickly

morphine heroine

they are painkillers used to control pain from injuries or allow athletes to train for longer . If they are being used in order to ignore an injury then athletes obviously risk doing further damage

they are a naturally occuring substance that circulates in the blood , and can imporve muscle growth , change the balance of other hormones and increase the production of red blood cells . which increases oxygen delivery

• insulin
• human growth hromone

when inhaled they relax the airways , allowing more oxygen to reach the blood .

not performance enhancing drugs on their own , but they are used to get rid of traces of other drugs

water as a temporary wieght loss measure in sports with weight categories

that there are other "undectable" drugs in use

skins patches can deliver a steady dosage of the drug which is harder to detect

of injecting genes deirectly into muscles , lungs or other targets may be used an this means that they will be almost impossible to detect