Nicotine
Nicotine
As an ingredient, nicotine is often criticised, especially in connection with addictive substances. Although nicotine poses health risks and is addictive, it is neither carcinogenic nor a major cause of smoking-related illnesses. However, due to the close connection between nicotine and tobacco and smoking, there are many misunderstandings about the risk potential of nicotine.
What exactly is nicotine, what forms does it come in, what foods do they occur in and how is it broken down? You can find all the facts below.
What is nicotine
Nicotine is a naturally occurring psychoactive substance found in many plants of the nightshade family, as well as some other plants. Small amounts of nicotine can be found in potatoes, tomatoes, aubergines and, of course, in the leaves of the tobacco plant (Nicotiana tabacum).
Where does the name come from
The name comes from the French diplomat Jean Nicot (1530–1600), who sent the first seeds of the tobacco plant to France. Jean Nicot was convinced of the healing properties of tobacco and recommended tobacco to the French queen Catherine de' Medici as a remedy for her migraines (1559). In 1753, the plant was named ‘Nicotiana’ by the botanist Linné in honour of Jean Nicot; this is also where the name ‘nicotine’ comes from.
Not all nicotine is the same
Tobacco refers to the dried leaves of the tobacco plant. Tobacco leaves contain over 5,000 individual substances, nicotine being one of them. The plant produces nicotine mainly in the roots. From there it is transported to the leaves, where it serves the plant as a natural defence against pests.
Graphic
Forms of nicotine
Natural nicotine
is extracted from tobacco leaves. Until recently, practically all nicotine - whether for medical nicotine replacement products or for tobacco-free oral nicotine pouches - came from the tobacco plant.
Nicotine is a chiral molecule: like many other substances (e.g. sugars, amino acids), nicotine can be built in a mirror-image fashion: as R-nicotine and as S-nicotine. Both forms are chemically identical, but have different biological properties. In nature, nicotine only occurs as the so-called S-form. This S-form is also the biologically active version of nicotine, while the R-form is not.
An illustrative example of this structure is our hands: although the left and right hands are identical in structure, they are mirror-inverted and not congruent.
Synthetic nicotine
For a long time, it was expensive and time-consuming to produce nicotine in the laboratory. In the meantime, industrial processes have been developed to selectively produce the S-form, i.e. synthetic but nature-identical nicotine, on a large scale. Synthetic nicotine is already used in some vapour products and could become a promising option for the industry in the future.
detailed scientific information
Nicotine salt
In this case, the nicotine is ‘bound’ with the anion of an organic acid. Important examples are nicotine benzoate or succinate. Chemically, these compounds are called ‘salts’. The vapour tastes less harsh and a higher availability via the lungs can be achieved. Many e-cigarette liquids contain so-called nicotine salts.
How is nicotine consumed?
Nicotine has a long history as a stimulant.
It was and is mainly consumed in combination with tobacco. Since Christopher Columbus brought tobacco from America to the Old World at the end of the 15th century, tobacco has been snuffed, chewed and smoked.
But nicotine can also be consumed without tobacco: as vapour from an e-cigarette, extracted from heated tobacco or from oral products via the oral mucosa. In addition, there are also medical nicotine replacement products in which the nicotine is absorbed via the oral mucosa, e.g. as chewing gum, and via the skin, e.g. with a patch.
The following diagram shows examples of the approximate nicotine intake for the respective categories.
Diagram of nicotine intake as PDF
How does nicotine work?
Nicotine stimulates the central nervous system. In doing so, nicotine can also have a calming effect. At the same time, nicotine can suppress appetite, stress, nervousness and tiredness. Nicotine activates the ‘reward centre’ in the brain and can thus create a feeling of well-being.
Nicotine achieves this effect by binding to so-called nicotinic receptors in the central nervous system. In general, receptors transmit signals in the body. After activation of the receptor, nicotine releases messenger substances such as dopamine or serotonin, which belong to the reward system in the brain. This is where a considerable addictive potential arises.
What are the risks?
Nicotine is toxic.
Particularly in high doses. In the short term and on a temporary basis, nicotine can cause nausea, sweating, diarrhoea and headaches, especially in people who are not accustomed to nicotine consumption.
However, nicotine does not damage the genetic material and is not carcinogenic. The use of nicotine in pharmaceuticals has been proven in clinical studies over many years.
Nevertheless, nicotine should not be underestimated: an oral intake of approx. 5 mg nicotine per kilogram of body weight can be fatal (that's 140 mg nicotine for an adult human of 70 kg or 50 mg for a toddler of 10 kg). During pregnancy, nicotine can increase the risk of miscarriage and premature birth.
Nicotine is addictive.
Nicotine is a psychotropic substance like alcohol, cocaine or caffeine and affects the central nervous system, influencing perception, thinking, feeling and action. While cocaine and opiates are controlled by the UN as psychotropic substances and are therefore illegal in many countries, alcohol, caffeine and nicotine are not listed by the UN. They are mostly considered legal ‘drugs’ and are widely used in many cultures.
Through nicotine consumption, the body gets used to the fact that many cells are ‘occupied’ by nicotine over time and forms more and more nicotine receptors. This can also lead to physiological dependence, which increases the potential for addiction. If nicotine is not available for a longer period of time, many of these receptors are suddenly unoccupied and less dopamine is released. Those affected experience withdrawal symptoms and develop a strong craving for a cigarette.
The reasons behind nicotine addiction are not yet fully understood. The speed at which nicotine enters the bloodstream can also influence the potential for addiction.
In the body
nicotine is quickly broken down in the liver. Half of the nicotine is already eliminated 2–2.5 hours after it is absorbed. Nicotine and its breakdown products are then excreted via the kidneys and in the urine. Cotinine is an important breakdown product of nicotine. Cotinin is so specific for nicotine that it is used as a biomarker in the laboratory to prove the consumption of nicotine. The degradation of cotinine takes longer, between 13 and 19 hours.
In water
According to ECHA, nicotine is readily biodegradable in water. Degradation occurs via microorganisms but also through UV light.