Caffeine's physical properties

Caffeine is both fat and water soluble. Caffeine is absorbed into the bloodstream from the intestine and is both fat and water soluble, meaning that it can enter the brain through the blood-brain barrier. This alkaloid is converted in the liver by enzymes which remove methyl groups from the molecule, resulting in theobromine, which gives various physiological effects such as anxiety, alertness, stamina, and withdrawal symptoms. The extent of the effects depends on the dose consumed. Caffeine is excreted via urine and the substance has a half-life of 3-6 hours.