How is nicotine excreted?

Nicotine is primarily metabolized in the liver, where it is converted into several metabolites, with cotinine being the most prominent. Once metabolized, nicotine and its metabolites are excreted primarily through the kidneys in urine. A smaller amount may also be eliminated through saliva, sweat, and breast milk. The excretion rate can be influenced by factors such as pH levels, age, and individual metabolic differences.