All About Nicotine: What is it and why is it bad for you?

October 5, 2021

Nicotine, the notorious stimulant used by Sherlock Holmes to both quit smoking and think better is a controversial chemical compound with both medicinal uses and harmful side effects.

Smoking is addictive for two main reasons — the first being the repeated muscle memory of moving the hand to the mouth, and the other being the chemical compound, endorphins, produced by the brain in response to nicotinic stimulation. Both of these lead to an addiction to cigarettes.

As such, to help smokers quit smoking, pharmaceutical companies have thus introduced nicotine products to help wean smokers off the habit of smoking.

While this may insinuate that nicotine patches/gums are safe, since they are, after all, prescribed by doctors and pharmacists, it is not necessarily true. To be accurate, the use of patches and gums are preferable to smoking, but nicotine itself as a compound is still harmful to us in many ways, which is why smoke-free vaping products which contain nicotine and other additives still exert negative health effects.

What is Nicotine?

Nicotine is a psychoactive substance that acts by speeding up neurological impulses from our body to our brain. It is, in fact, a very powerful stimulant, much more so than caffeine. Nicotine, other than being consumed recreationally via smoking or vaping, has also been used for performance-enhancing purposes due to its stimulant effects. However, it is not regarded to be safe for such use due to its ability to trigger dependence in just a matter of days.

Effects of smoking on the respiratory system

Nicotine affects the respiratory system through three paths.

  • Direct exposure of nicotine and its products to the lungs
  • Effects of nicotine and its byproducts on the central nervous system
  • An increased risk of cancer due to the metabolites of nicotine and its products

Effects of direct exposure

Smoking may lead to emphysema in smokers, characterised by shortness of breath because of the destruction of the lung’s air spaces.

Effect on the central nervous system (CNS)

Nicotine and its products influence the CNS by stimulating the vagal reflex and parasympathetic ganglia. This results in difficulty breathing as a result of bronchoconstriction, whereby the airways in the lungs narrow.

In one study, nicotine was injected into the brain and subjects had their brain signals as well as breathing patterns monitored. Those with nicotine injected into their brains had an increased frequency of signal bursts leading to a shallower and more rapid rhythm of respiration.

Risk of cancer

There are multiple studies linking nicotine and its products to tumour progression and metastasis (spread of cancer) via a number of mechanisms (increased angiogenesis. Essentially, this means that consumption of nicotine increases the chance of tumours growing to larger sizes and increasing the chances of them spreading beyond the lungs to other systems.

Metastasis is a critical step of cancer advancement that turns early-stage cancers into late-stage ones that are more difficult to treat. Nicotine further assists the development of cancer by increasing the blood supply and blood flow to the growing tumour cells.

Effects on Cardiovascular System

Nicotine also takes a toll on the cardiovascular system by altering the flow of blood in our body in unique ways. As such, long term use of nicotine increases the chance of coronary artery diseases and vascular diseases since the heart will be deprived of nutrients and oxygen. Nicotine may also thicken the lining of blood vessels and smooth muscles in the heart, which further contributes to restricted blood flow around the heart.

These effects, simply put, increase the chances of heart disease and cardiovascular diseases such as hypertension.

Effects on other systems

Beyond the lungs and the heart, nicotine adversely affects our kidneys, immune, reproductive and ocular functions as well. Some of which include:

  • Increased chance of renal failure
  • Weakened immune system
  • Cataract formation
  • Disrupted/altered menstrual cycles
  • Reduced fertility


In conclusion, nicotine, in the form of a cigarette or otherwise, is not safe and should not be consumed. If used, it should only be used under medical advice to help with smoking cessation, and not to be used recreationally because of its many unwanted side effects.

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