coffee

[alia72]

after how much time the caffien concentration level in blood reaches half? wat is caffein half life?

[qapmoc]

Hi alia72,   Caffeine is  absorbed through the stomach and small intestine into the bloodstream.   The amount of caffeine in the blood reaching the brain determines the severity of its effects on the body. Caffeine is metabolized by the liver and eventually its metabolites are excreted in urine, although caffeine can also be secreted in saliva, semen, and breast milk. Caffeine will continue to have an effect on the body as long as it remains in the blood. The time required for the body to eliminate one-half of the total amount of caffeine consumed this varies from several hours to several days.   For the average non-smoking adult the effects last about five to seven hours. Several factors can lengthen caffeine's half-life, such as some medications, liver diseases, pregnancy. The half-life of caffeine in a pregnant women is 18-20 hours; the half-life in women taking oral contraceptives is up to 13 hours. Other factors, such smoking and age can shorten caffeine's half-life. For example, in children and smokers the half-life averages about 3 hours.