What Is Nicotine? - Facts, Addiction & Withdrawal Symptoms

Instructor: Marisela Duque

Marisela teaches nursing courses at the college level. She also works as a unit educator, teaching experienced nurses about changes in nursing practice.

Upon completion of this lesson, you will be able to define what nicotine is, identify why nicotine is addictive, and describe withdrawal symptoms. A short quiz follows the lesson.

Tobacco and Nicotine

Nicotine is a naturally-occurring chemical found in tobacco plants. This substance can be found in products that contain tobacco such as cigars, cigarettes, and chewing tobacco. It is highly addictive and, in its purest form, deadly. A single drop of pure, liquid nicotine on the tongue is enough to kill you. In fact, its lethality is why nicotine was used as a very effective and organic pesticide for hundreds of years!

Why is Nicotine Addictive?

When you use tobacco products, the nicotine gets absorbed through your lungs into your blood, quickly reaching your brain. It affects the human body by stimulating a type of protein receptor in the brain called a nicotinic acetylcholine receptor. Once the receptor has been activated, a release of adrenaline is triggered, causing you to feel more energized and focused. With the release of adrenaline and other chemicals in the body, blood vessels constrict and the heart rate increases. In the central nervous system, the receptors release dopamine, a feel-good hormone that contributes to the adrenline 'buzz'.


The buzz of pleasure that follows using nicotine products, including chewing tobacco or even electronic cigarettes, is a main consideration in the addictiveness of nicotine. That pleasurable sensation fades relatively quickly after it nicotine enters your blood stream and its departure can leave you feeling run down and tired. This 'down' sensation, quite the opposite of the adreneline/dopamine buzz, is what makes smokers want to light up another cigarette.

Individuals who inhale or absorb nicotine on a regular basis soon build up a tolerance to the effects of the drug and find themselves lighting up (or chewing) more frequently in order to feel that buzz. The cycle of up and down repeats over and over again, leading to addiction. Once you become addicted to nicotine, it can be very difficult to quit. Research shows that the younger you start smoking, the more addictive nicotine can be. As of 2013, about 75% of high school smokers become adult smokers.

Health and Withdrawal

Nicotine addiction can lead to many chronic health problems. Persons that use nicotine products are at an increased risk for cancer, heart disease, emphysema, and hypertension, to name a few. According to the National Cancer Institute (2011), smoking causes about 443,000 deaths a year, including 49,000 deaths due to secondhand smoke.

Since nicotine is addictive, quitting will cause symptoms of withdrawal. Persons going through withdrawal may experience:

  • Anxiety
  • Irritability
  • Headache
  • Hunger and weight gain
  • Nicotine cravings

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