Nicotine

Tobacco smoke has hundreds of harmful chemicals in it and its effects on human health are well documented.  Tobacco smoke is synonymous with nicotine, one of the chemicals in tobacco plants, which begs the question: Is it the nicotine component of tobacco smoke that is so extremely harmful?

What is nicotine?

Nicotine is a nitrogen-containing chemical found in the tobacco plant, and it can also be created synthetically.  Nicotine comes from the Nicotiana species, which are tobacco plants that form part of the nightshade family, along with eggplant, red peppers, tomatoes, and potatoes.

Tobacco plants originated in South America where it was cultivated by indigenous people, who used the leaves to chew, smoke, or for use in religious rituals.   It was later introduced to Europe and other parts of the world and became widely cultivated globally.

Any product containing tobacco also contains nicotine. 

Effects of nicotine on the body:

Most smokers use tobacco regularly because they are addicted to nicotine.  Nicotine levels peak within 10 seconds of inhalation.  As cigarette smoke enters the lungs, the nicotine component is absorbed rapidly into the bloodstream and delivered quickly to the brain.   The acute effects of nicotine dissipate quickly, resulting in smokers continuing smoking to maintain the pleasurable effects of nicotine and to prevent withdrawal symptoms.

Nicotine impacts various parts of the body in different ways, as it acts as both a sedative and a stimulant.

• Nicotine as sedative: Once nicotine reaches the brain, and depending on the dose, it can trigger the release of beta-endorphin, which is a hormone that has the ability to reduce anxiety, also creating a sense of well-being, and easing emotional distress.
• Nicotine as stimulant: Similarly to drugs such as heroin or cocaine, nicotine causes dopamine (a brain chemical that affects movement, emotions, and sensations of pleasure and pain) to be released in certain brain regions, which leave the smoker feeling happier and more satisfied.  The surge in the reward circuits of the brain causes a slight, brief euphoria, which is much briefer than the ‘high” associated with other drugs.  Nicotine also often results in experiencing a “kick”, which is partly caused by nicotine stimulating the adrenal glands, releasing the hormone adrenaline.  This surge in adrenaline stimulates the body, as it causes an immediate release of glucose and increased blood pressure, heart rate, and breathing activity.  Nicotine also causes the pancreas to release less insulin, resulting in a slight increase in blood sugar (glucose) levels.
• Nicotine addiction: Repeated exposure to nicotine reduces the sensitivity of the circuits in the brain to dopamine.  Long-term brain changes from continued exposure to nicotine result in addiction, which leads to withdrawal symptoms when not smoking.  It makes it difficult to quit smoking and statistics in the USA indicate that only about 6% of smokers manage to quit permanently in a given year.
• Benefits of nicotine: Nicotine is associated with the harmful effects of smoking, but cigarette smoke contains hundreds of harmful chemicals, some carcinogenic, apart from the nicotine component.  Nicotine can offer some benefits, such as reduced anxiety due to increased levels of beta-endorphin, increased levels of euphoria, alertness, and relaxation, as well as improved concentration and memory due to increased activity of certain neurotransmitters in the brain.

Other sources of nicotine:

Apart from smoking tobacco products, an increasingly popular trend amongst younger generations is vaping, which involves inhaling a vapour created by using an electronic cigarette (e-cigarette).  Using an e-cigarette will in many cases still expose the user to nicotine.  Depending on the regulations of different countries, the ingredients in e-cigarettes may not be well regulated and often contains harmful ingredients such as diacetyl (a food additive used to flavour e-cigarettes that can damage small passageways in the lungs); acrolein (a chemical commonly used as weed killer that can damage the lungs); and formaldehyde (a toxic chemical that can cause lung- and heart disease).  Diacetyl is one of the chemicals associated with inflammatory obstruction of the tiniest airways in the lung called bronchioles, a condition commonly known as “popcorn lung”. 

As e-cigarette fluids often contain oils, vaping may cause a condition called lipoid pneumonia, which is caused when fat or oil gets into the lungs and results in the air sacs becoming inflamed and filled with fluid.

Many of the chemicals commonly found in e-cigarettes, such as formaldehyde, toluene, and nitrosamines, have carcinogenic properties which may cause cancer over the longer term. 

However, at this point in time not enough is known about the potential long-term risks of e-cigarette use.

Nicotine dependence:

Nicotine dependence describes the condition when your body craves nicotine, and you can’t stop using it.  Nicotine is the chemical in smoked tobacco that is responsible for the urge to smoke in order to experience pleasant feelings.  These effects are short-lived, which feed the need for another cigarette, cigar, or pipe bowl.  As your body gets used to smoking tobacco, you need more nicotine to experience the same effects. 

Trying to quit smoking makes the person go through mental and physical changes that are not pleasant.  Symptoms of nicotine dependence include symptoms such as being unable to stop smoking; smoking within 30 minutes of waking up; and continuing to smoke despite health problems. 

Nicotine withdrawal symptoms are physical and mood related problems and can include anxiety, strong cravings, restlessness, irritable mood, depression, frustration, anger, increased hunger, and trouble focusing or sleeping.

When quitting smoking, nicotine cravings get easier to handle after the first few weeks as symptoms lessen and the urge to smoke goes down.  People who smoke also get into the habit of smoking, besides the nicotine effects.  For some people it is this smoking habit that is even more difficult to conquer than the craving.

Effects of smoking on the body:

At least 69 of the hundreds of harmful chemicals in tobacco smoke can cause cancer.  Cigarette smokers are much more likely to develop and die from certain diseases than people who don’t smoke, and smoking has been linked to many different health issues, such as:

• Smoking causes lung diseases such as emphysema and chronic bronchitis.
• Smoking makes asthma worse.
• Smoking is the leading cause of lung cancer deaths.
• Smoking raises the risk of many other types of cancer, such as cancer of the mouth, throat, larynx, esophagus, pancreas, bladder, kidney, and some types of leukemia.  Statistics indicate that smoking causes 30% of all cancer deaths in the USA.
• Smoking raises the risk of developing and dying of heart and blood vessel diseases, including stroke and heart attack.
• Smoking raises the risk of developing type 2 diabetes.
• Smoking raises the risk of developing cataracts and macular degeneration in the eyes.
• Smoking raises the risk of gum disease and tooth loss.
• Smokers are more likely to get respiratory infections such as colds, flu, and bronchitis.

Conclusion:

Many fail to differentiate between smoking and nicotine and view it as the same problem.  Long term inhalation of the harmful components of smoked tobacco products leads to adverse health conditions and even death, and not the nicotine as such.  Apart from its very addictive nature, nicotine, as such, carries little risks in healthy adults.  It is the multitude of toxic chemicals released by tabacco burning / smoking, not nicotine, that leads to serious health problems and even death.

References:

Nicotine: The good, the bad & the ugly.  Published 29 March 2025.  Echelon Health. (A health assessment company.)  UK.  (www.echelon.health)

Nicotine dependence.  Published 14 June 2025.  Mayo Clinic.  USA.  (www.mayoclinic.org)

How smoking and nicotine damage your body.  Reviewed 5 January 2024.  American Heart Association.  (www.heart.org)

Nicotine is not the problem.  Published 10 June 2024.  R Street Institute.  (A Think Tank.)  USA.  (www.rstreet.org)

Everything you need to know about nicotine.  Updated 1 July 2024.  Medical News Today.  (www.medicalnewstoday.com)

Is nicotine addictive?  Published January 2020 in Tobacco, Nicotine, and E-cigarettes Research Report.  National Institute on Drug Abuse.  National Institutes of Health.  USA.  (www.nida.nih.gov)

What are the physical health consequences of tobacco use?  Published January 2020 in Tobacco, Nicotine, and E-cigarettes Research Report.  National Institute on Drug Abuse.  National Institutes of Health.  USA.  (www.nida.nih.gov)

HEALTH INSIGHT.