Addiction Nicotine Use Nicotine Withdrawal Important Facts About Nicotine By Terry Martin Terry Martin Facebook Twitter Terry Martin quit smoking after 26 years and is now an advocate for those seeking freedom from nicotine addiction. Learn about our editorial process Updated on October 11, 2021 Medically reviewed Verywell Mind articles are reviewed by board-certified physicians and mental healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Armeen Poor, MD Medically reviewed by Armeen Poor, MD Armeen Poor, MD, is a board-certified pulmonologist and intensivist. He specializes in pulmonary health, critical care, and sleep medicine. Learn about our Medical Review Board Print Oscar Sánchez Photography/Moment Open/Getty Images Nicotine is a colorless alkaloid chemical that is most commonly sourced from the tobacco plant, which is in the nightshade family of plants. Nicotine is also present in small amounts in tomato, potato, green pepper, eggplant, and coca plants. Most commonly known as the addictive ingredient in tobacco products, nicotine is often mistakenly thought to be a harmless chemical otherwise. While research is ongoing regarding nicotine and how it affects the human body, a number of facts about the hazards of nicotine are available today, some of which might surprise you. How Nicotine Affects Body Chemistry When inhaled, nicotine travels to the brain quickly (within 10 seconds) and attaches to receptors where the neurotransmitter acetylcholine would normally dock. This starts a chain of chemical reactions that influence numerous bodily functions. Nicotine is a stimulant, but depending on the smoker's mental and physical state, it can be perceived as energizing or relaxing. Most smokers are familiar with the feeling of a racing heart and/or shallow breathing when they smoke. Adrenaline, the 'fight or flight' hormone is responsible for this. When nicotine reaches the brain, adrenaline is released, increasing heart rate, blood pressure, and restricting blood flow to the heart. Adrenaline also tells the body to move excess glucose into the bloodstream. At the same time, nicotine hinders the release of insulin from the pancreas, which would remove excess sugar from the blood. The result is that smokers are often in a state of hyperglycemia, meaning they have more sugar in their blood than is normal. High blood sugar dampens hunger, and this is a contributing factor to the appetite-suppressant effects of nicotine. Dopamine is another neurotransmitter that is activated when nicotine reaches the brain. Dopamine causes feelings of euphoria and is thought to play a significant role in addiction. Nicotine: Everything You've Been Afraid to Ask Nicotine Is Poisonous Nicotine is extremely poisonous. While no exact figure has been established for a lethal dose, a recent study estimated a lower limit of 0.5–1 g. That said, tobacco products do not contain enough nicotine to cause a fatal overdose when used as directed. For example, a typically manufactured cigarette contains about 10 mg of nicotine, but most of it goes up in smoke, with approximately one milligram of nicotine being inhaled by the smoker. Nicotine can be lethal to children in doses as small as 10 milligrams. Plants produce nicotine to protect themselves from predators, and people use nicotine in pesticides for the same reason. Nicotine can be absorbed through the skin, which is the delivery method with the nicotine patch. A spill of electronic cigarette nicotine solution (known as e-juice) can be hazardous for this reason. Researchers have discovered that the nicotine in secondhand smoke can be absorbed through bare skin that is exposed to the smoke. It can also be absorbed into the skin from clothing that has been contaminated by nicotine. Ingredients and Additives in Cigarettes Risks of Nicotine Exposure for Children and the Unborn Child Nicotine is present in the residue left behind by cigarette smoke in a closed environment, also known as third-hand smoke. This presents a danger to small children who may ingest nicotine on toys and small hands that find their way to a child's mouth. Young children are also at risk of nicotine poisoning from chewing on full cigarettes/cigarette butts, or NRT products like nicotine gum or nicotine patches. Please keep these items out of the reach of children. Nicotine may decrease the ability of sperm to fertilize eggs by as much as 75%. Nicotine docks with receptor sites on sperm cells and impedes their viability in men who are heavy smokers. Nicotine causes blood vessels to constrict. In pregnant mothers, this translates to less oxygen and nutrients delivered to the fetus. Nicotine easily crosses the placental barrier and can be detected in both fetal circulation and amniotic fluid. At this time, it is not known how much nicotine in vitro would be considered fatal for the fetus. Nicotine accumulates in breast milk, is passed on to nursing infants, and appears to affect their sleep patterns. How Nicotine Can Hurt Your Health Research has uncovered a link between nicotine and vascular smooth muscle cell damage, contributing to the formation of plaques that lead to heart disease. Nicotine slows the production of bone-producing cells called osteoblasts. This prolongs healing when bones are broken. Nicotine inhibits apoptosis, a process that removes unwanted cells in the body (programmed cell death). Since some of the cells targeted by apoptosis are mutations that may become cancerous in the future, inhibiting this important function may contribute to life-threatening diseases. Smoking is a known risk factor for degenerative disc disease. Nicotine and carbon monoxide in cigarette smoke hinder spinal disc cells from absorbing vital nutrients in blood, which in turn leads to premature dehydration and degeneration of spinal discs. Nicotine is among the most toxic of all poisons and is highly addictive. It is a mistake to think that using nicotine in a form that doesn't involve cigarettes is harmless. Products like smokeless tobacco and electronic cigarettes may be considered less harmful when compared to cigarette smoking, but they carry considerable health hazards as well. And don't forget, while nicotine addiction is actively engaged, ex-smokers are at a heightened risk for a full-fledged smoking relapse. Don't settle for less than you deserve. Recovery from nicotine addiction takes some work, but it is doable and so rewarding. Life works better on every level when we free ourselves from the self-imposed prison addiction puts us into. Health Benefits of Quitting Smoking 13 Sources Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Valentine G, Sofuoglu M. Cognitive Effects of Nicotine: Recent Progress. Curr Neuropharmacol. 2018;16(4):403-414. doi:10.2174/1570159X15666171103152136 Tweed JO, Hsia SH, Lutfy K, Friedman TC. The endocrine effects of nicotine and cigarette smoke. Trends Endocrinol Metab. 2012;23(7):334-42. doi:10.1016/j.tem.2012.03.006 Mayer B. How much nicotine kills a human? Tracing back the generally accepted lethal dose to dubious self-experiments in the nineteenth century. Arch Toxicol. 2014;88(1):5-7. doi:10.1007/s00204-013-1127-0 Bassett RA, Osterhoudt K, Brabazon T. Nicotine poisoning in an infant. N Engl J Med. 2014;370(23):2249-50. doi:10.1056/NEJMc1403843 Nicotine Keeps Leaf-Loving Herbivores at Bay. PLoS Biol. 2004;2(8):e250. doi:10.1371/journal.pbio.0020250 Jacob P, Benowitz NL, Destaillats H, et al. Thirdhand Smoke: New Evidence, Challenges, and Future Directions. Chem Res Toxicol. 2017;30(1):270-294. doi:10.1021/acs.chemrestox.6b00343 University at Buffalo. Men Who Smoke Heavily May Impair Sperm, Fertility. Wickström R. Effects of nicotine during pregnancy: human and experimental evidence. Curr Neuropharmacol. 2007;5(3):213-22. doi:10.2174/157015907781695955 Yoshiyama S, Chen Z, Okagaki T, et al. Nicotine exposure alters human vascular smooth muscle cell phenotype from a contractile to a synthetic type. Atherosclerosis. 2014;237(2):464-70. doi:10.1016/j.atherosclerosis.2014.10.019 Kim BS, Kim SJ, Kim HJ, et al. Effects of nicotine on proliferation and osteoblast differentiation in human alveolar bone marrow-derived mesenchymal stem cells. Life Sci. 2012;90(3-4):109-15. doi:10.1016/j.lfs.2011.10.019 Zeidler R, Albermann K, Lang S. Nicotine and apoptosis. Apoptosis. 2007;12(11):1927-43. doi:10.1007/s10495-007-0102-8 Steelman T, Lewandowski L, Helgeson M, Wilson K, Olsen C, Gwinn D. Population-based Risk Factors for the Development of Degenerative Disk Disease. Clin Spine Surg. 2018;31(8):E409-E412. doi:10.1097/BSD.0000000000000682 Korfei M. The underestimated danger of E-cigarettes - also in the absence of nicotine. Respir Res. 2018;19(1):159. doi:10.1186/s12931-018-0870-4 Additional Reading Monell Chemical Senses Center. Nicotine in Breast Milk Disrupts Infant's Sleep Patterns. National Institute on Drug Abuse. Drug Facts: Cigarettes and other Tobacco Products. National Institutes of Health. Effects of Nicotine During Pregnancy: Human and Experimental Evidence. Wiley Online Library. Measurements of Dermal Uptake of Nicotine Directly from Air and Clothing. International Programme on Chemical Safety. Nicotine. By Terry Martin Terry Martin quit smoking after 26 years and is now an advocate for those seeking freedom from nicotine addiction. See Our Editorial Process Meet Our Review Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit Get Treatment for Addiction Advertiser Disclosure × The offers that appear in this table are from partnerships from which Verywell Mind receives compensation.