The active ingredient in tobacco cigarettes, NRT and electronic vaping devices.

But what does nicotine do?

A Short History

Nicotine is a naturally occurring chemical (alkaloid) which is present in many vegetables and plants such as aubergines, cauliflower and ripe or green tomatoes according to the New England Journal of Medicine, but most notably in tobacco. Between 1559 when tobacco was introduced to Europe and until the end of the Second World War nicotine was also very commonly found as an insecticide but was phased out and eventually abandoned due to the easier availability of other insecticides and the harmful effects of nicotine to livestock and animals who ingested plants that had been treated with it.

Like caffeine, nicotine is a strong stimulant and best known for its highly addictive properties in cigarettes, which are as strong physically as they are psychologically and make for a habit notoriously difficult to break. Although nicotine is technically not especially addictive on its own, when paired with the substances in a cigarette it becomes is the driving force behind the smoking habit.

The structure of nicotine is such that the majority of it burns up and dissipates at relatively low temperatures (35 °C/95 °F) before it ever reaches the smoker’s lungs, what does reach the smoker is easily enough to keep the smoker hooked.

Nicotine and Your Body

Nicotine is a stimulant drug that works in a very unique way; it seems to cause stimulation in low doses and relaxation in high doses, the more you take the more it changes from stimulant to relaxant and research suggests that the stimulating effects of alertness, sharpness are achieved with short quick puffs whereas the relaxing calming effects tend to be better reached by long slow puffs. This behaviour makes nicotine a very unique substance as all other drugs work in the opposite way. The amount of nicotine the body absorbs through smoking depends on a number of things including the brand of cigarette, type of tobacco and even the use of a filter or not.

Nicotine has a hand in curbing appetite and raising a person’s metabolism which usually results in weight loss for many smokers. However once you stop smoking these will return to normal and this means putting that weight back on, sometimes quickly. This is yet another reason why many people are hesitant about quitting the smoking habit.

When smoked through a cigarette, nicotine will reach your brain in approximately seven seconds creating an instant burst of euphoria, relaxation and relief when the brain releases a neurotransmitter called dopamine (the feel good factor) in the reward circuits of the brain. The most common effects reported are relaxation, alertness, relief, stress relief and concentration.

For almost any smoker/addict smoking a cigarette is generally known to temporarily improve mood and even relieve minor depression in some cases, raise the level of sugar in the blood by increasing insulin production in the body, raise your heart rate by around 10 - 20 bpm, tighten your blood vessels and by extension raise your blood pressure and stimulate your memory and alertness. The trade off to all this is though is a susceptibility to strokes, heart disease, poor memory and bouts of bad mood swings or even depression between cigarettes and that’s before you start to factor in the effects of tobacco’s 7000 plus chemicals on your body.

Nicotine Effects and Dangers

Nicotine is a stimulant drug like caffeine; in large enough doses it has the potential to be dangerous in almost any context. At toxic doses (30-60mg) nicotine can cause contractions and respiratory paralysis, which can result in death. It can easily pass through skin to enter the blood stream which is why nicotine patches are used as an effective smoking cessation aid.

Spilling a large enough amount of it onto the skin can cause intoxication or even death. That said it’s unlikely someone will overdose on nicotine just by smoking even if they are heavy smokers, but it is possible to overdose accidentally by smoking cigarettes while wearing a nicotine patch or chewing nicotine gum.

Nicotine increases blood pressure and heart rate in humans, and is known to increase LDL (the unhealthy cholesterol) creating arterial problems where an artery wall thickens and becomes narrow when fatty substances like cholesterol build up in it, this is similar a condition called Atherosclerosis. This effect on arteries puts smokers more a risk to a heart attack or a stroke. As stimulant nicotine can in some very rare and extreme cases cause the uncomfortable feeling of akathisia, or restless leg syndrome which forces a need to keep moving your legs to stop a very unpleasant feeling in them.

There is a study in Denmark conducted on some 70,000 women found that women who used nicotine gum and patches during the early stages of pregnancy, specifically in the first 12 weeks faced an increased risk of having babies with birth defects, a risk of about 60% compared to women who were non-smokers.

Nicotine like any other stimulant can be especially dangerous if used in large quantities like smoking or abusing nicotine reduction therapy, during pregnancy or if ingested by small children. As we mentioned earlier it is found in a number of fruit and vegetables which are consumed by people daily, it only becomes dangerous if misused or taken in massive quantities.

Nicotine Addiction, the Smoker's Snare

A little known fact about nicotine is that it’s not immensely addictive on its own, if it was there would be a lot of aubergine, tomato and cauliflower addicts running around in the world. Nicotine’s addictive effect on the brain works in tandem with a number of other things.

The natural combination of nicotine and other potentially strong antidepressants (MAOI) found in tobacco possibly coupled with what psychologists sometimes call oral addiction (the connection made by a child sucking its thumb, or a baby breast feeding for example) create a strong habit based as much on physical addiction as it is on psychological conditioning. The actual addictive quality of nicotine seems to be strongly connected to the way it increases the amount of the neurotransmitters dopamine (feel good factor) and norepinephrine (memory) and endorphins (pain management) in the mesolimbic pathway (reward circuits) of the brain which gives feelings of euphoria and relaxation when a cigarette is smoked.

The brain tries to compensate for this fake hike in neurotransmitter by reducing production of them and then tries to compensate for that by upping the number of receptors that will pick them up. The result is an increase of this reward circuit’s sensitivity which makes desire for more nicotine very intense due to the feel good dopamine factor, the memory of how good it will feel from the effects of norepinephrine and the rush from endorphin release. This change of neurotransmitter behaviour in the brain can persist for months after you’ve given up smoking making the danger or starting up again very real.