Nicotine is the active ingredient in cigarettes, cigars, chewing tobacco, and other tobacco products. It’s a stimulant, which means it increases the activity of your central nervous system.
When nicotine enters your bloodstream, it promotes the release of two neurotransmitters: dopamine and epinephrine. The release of these brain chemicals can lead to a pleasurable “rush” or “kick.” Because nicotine also stimulates the reward centers of your brain, it’s highly addictive.
Nicotine can be linked to a variety of side effects. One of these is headache.