A Guide to Nicotine

By The Fix staff 07/10/14

Nicotine is a chemical found in the leaves of the tobacco plant that is so powerful and toxic it has been widely used as an insecticide. When tobacco smoke is inhaled, nicotine is absorbed through the lungs and reaches the brain in about 10 seconds. There it works by mimicking the actions of a naturally occurring brain chemical, acetylcholine, which joins with special receptors. Some nicotine receptors in the brain activate part of the pleasure center, which is directly associated with the mild euphoric effects accompanied by nicotine use. 

How is Nicotine Used?

Nicotine is found in tobacco products: cigarettes, cigars, pipe and chewing tobacco. It is also used in a number of products that are designed to help people quit smoking tobacco products. It is absorbed through the skin and mucosal lining of the nose, mouth, or in the lungs when smoked as part of a cigarette. Cigar and pipe smokers do not inhale the smoke so the nicotine is absorbed more slowly through the mucosal membranes of their mouths. With chewing tobacco, users place the product, or “dip” as it is commonly known, inside the mouth between the cheek and gum, or upper lip. The nicotine inside chewing tobacco is ingested through the mucosal membranes of the mouth.

How Does Nicotine Affect the Brain?

Nicotine is a highly addictive stimulant that can enhance brain activity and concentration while creating an immediate dependency in the user. Nicotine imitates the action of the brain’s natural transmitter, acetylcholine, and binds to a type of acetylcholine receptor, known as the nicotinic receptor. Nicotine is not regulated within the brain or body. The drug stimulates the adrenal glands, resulting in a discharge of adrenaline. The rush of adrenaline stimulates the body and causes an increase in blood pressure, respiration, and heart rate.

A key brain chemical involved in mediating the desire to consume drugs is the neurotransmitter dopamine, and research has shown that nicotine increases levels of dopamine in the reward circuits. This reaction is similar to that seen with other drugs of abuse and is thought to underlie the pleasurable sensations experienced by many smokers. For many tobacco users, long-term brain changes induced by continued nicotine exposure result in addiction.

Nicotine’s pharmacokinetic properties also enhance its abuse potential. Cigarette smoking produces a rapid distribution of nicotine to the brain, with drug levels peaking within 10 seconds of inhalation. However, the acute effects of nicotine dissipate quickly, as do the associated feelings of reward, which causes the smoker to continue dosing to maintain the drug’s pleasurable effects and prevent withdrawal.

Nicotine withdrawal symptoms include irritability, craving, depression, anxiety, cognitive and attention deficits, sleep disturbances, and increased appetite. These symptoms may begin within a few hours after the last cigarette, quickly driving people back to tobacco use. Symptoms peak within the first few days of smoking cessation and usually subside within a few weeks. For some people, however, symptoms may persist for months.

Signs of Abuse

Users of nicotine commonly build a tolerance for nicotine infused products requiring larger quantities to achieve the same effect. Serious withdrawal symptoms occur when the user stops using the substance. These usually include: depression, anxiety, nausea, irritability, headaches, restlessness, increased appetite or weight gain, and difficulty concentrating. 

Abusers of nicotine may also exhibit the presence of dependent behaviors. Dependent behaviors for nicotine abuse include: preoccupation with tobacco, hiding or sneaking cigarettes, rituals around buying or using tobacco, and choosing lifestyles that revolve around the availability of tobacco. 

Long-Term Effects of Abuse

Aside from causing high blood pressure during use, nicotine itself has not been proven to have any other long-term negative effects. Nicotine acts as an addictive agent that binds people to smoking tobacco which then can lead to asthma, birth defects, bronchitis, cancer, diabetes, erectile dysfunction, heart disease, low bone density, pneumonia, and stroke. Long-term effects from ingesting smokeless tobacco products with nicotine include: permanent gum and tooth loss, lost or weakened sense of taste, mouth cancer, and throat cancer.


It is unlikely that a user could suffer from nicotine poisoning through smoking. Most cases of nicotine poisoning have been the result of its use as an insecticide.

Mixing with Other Drugs

Aside from the multiple long-term effects of smoking, there is no evidence that mixing nicotine use with substances such as marijuana, alcohol, or prescription pills provides any additional damage. 

Drug Tests

During a blood test for nicotine, a lab can measure either the presence or absence of nicotine or an absolute level of the toxins. A blood sample will be drawn for this test. If the lab is testing for nicotine levels, the nicotine will typically be gone within 1-3 days after you stop using tobacco.

Legal Status

Under U.S. law nicotine is a legal stimulant for people over the age of 18 years old.  

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