What is the primary addictive substance found in tobacco?

The primary addictive substance found in tobacco is nicotine. Nicotine is a natural stimulant that is highly addictive when consumed through tobacco products such as cigarettes, cigars, or chewing tobacco. It is absorbed into the bloodstream through the lungs or oral mucosa, reaching the brain within seconds and resulting in increased production of dopamine, a neurotransmitter associated with pleasure and reward. This pleasurable sensation reinforces the desire to continue using tobacco, leading to dependency and addiction. Additionally, nicotine withdrawal symptoms can arise when trying to quit, further reinforcing the addictive nature of this substance.