More than 80% of the people who smoke cigarettes began to smoke before the age of 18. About 5% started smoking at age 8, and another 20% started before age 13.¹

Nicotine is only one of more than 4,000 chemicals in tobacco, but it is the major component that acts on the brain. The lungs readily absorb nicotine from the smoke of cigarettes, cigars, or pipes. The tissues of the mouth can also absorb nicotine when smoking cigars or pipes, or when tobacco is chewed.

Nicotine reaches the brain within seconds and has a direct effect on the body for up to 30 minutes. When a person uses tobacco regularly, the levels of nicotine accumulate in the body during the day and persist overnight, exposing the person to the effects of nicotine for 24 hours.

In the body, nicotine acts as both a central nervous system stimulant and sedative. The person immediately feels the stimulant effect and pleasurable sensation. It increases alertness, relaxes muscles, improves memory and attention, and decreases irritability. The stimulant effect causes a sudden increase in blood pressure, breathing rate, and heart rate. The central nervous system stimulation is followed by depression and fatigue, causing the person to want another cigarette.

Nicotine is one of the most addictive substances. Some teens show early signs of addiction within days to weeks after starting to smoke. Repeated tobacco use causes a need for increasingly large amounts of nicotine to feel the same effect (tolerance) and withdrawal symptoms if the person tries to quit.

Smoking affects a person's appearance by causing bad breath, yellow teeth and fingernails, and wrinkles. Tobacco also leads to serious health problems, including:

• Long-term (chronic) cough, shortness of breath, and wheezing.
• Increased risk for heart disease, lung and other cancers, stroke, and emphysema.
• Increased risk among women for having babies with a low birth weight, which may result in the death of the baby. Women who smoke are also at risk for menstrual problems, early menopause, and osteoporosis.
• Increased risk among men for erection problems.

Signs of use

• Cigarette odor on clothing
• Cigarette or other tobacco product packages or wrappers in wastebaskets
• Sudden need for a teen to go outside or to the bathroom after meals
• Decrease in appetite

Strawberry-, cinnamon-, orange-, or chocolate-scented cigarettes called bidis, beedies, or beadies have become popular with teens in some areas of the United States. These cigarettes are made in India and are shaped like marijuana joints. They are unfiltered and have a 28% higher nicotine concentration than regular cigarettes.