What Do Caffeine and Nicotine Have in Common?

(Ever thought while enjoying your morning coffee that you were sipping a giant ashtray? Well, don’t worry, you’re not! But caffeine and nicotine do have a lot in common).

Photo by Julius Schorzman

Photo by Julius Schorzman

What do caffeine and nicotine have in common?  The science stuff:  Both are alkaloids and derived from plants and natural anti-herbivore chemicals. Both readily cross the blood brain barrier that separates the blood stream from the interior of the brain. The basics:  Both caffeine and nicotine are stimulants.  Both increase alertness and concentration and are addictive…but you knew that, didn’t you?


Caffeine is found in beans, leaves and the fruit of some plants. Basically, it acts as a natural pesticide in plants, where it paralyzes or kills insects that feed on the plant. In humans, however, it acts as a stimulant. The most common means of caffeine consumption by humans is beverages prepared from coffee beans and tea leaves. It is also present in various foods and beverages prepared from the kola nut. Other natural sources include plants of species of holly and guarana.

As a central nervous system stimulant, caffeine restores wakefulness by warding off drowsiness, the primary reason for the popularity of coffee, tea, soft drinks and energy drinks. Regular consumption often leads to tolerance. In people who are not tolerant to caffeine it increases the flow of urine when administered in sufficient quantities.

Caffeine is a metabolic stimulant commonly used recreationally…that may sound like a strange way to describe such a common part of our lives, but it’s true. It is also used medically to reduce fatigue. It is absorbed quickly, within 45 minutes, by the stomach and intestines and then transported throughout the body. Caffeine crosses the blood-brain barrier easily and works as a non-selective agonist and combines with adenosine receptors on the surface of cells. Adenosine is a functional nucleotide that is found in every part of the body and plays a significant role in metabolism and is necessary for RNA synthesis.

Once inside the body, caffeine starts having its effect within 30 minutes and when taken in mild quantities, the effect wears off in three to four hours. There is only a temporary reduction in feeling of tiredness and as such, it is an effective external aid for enhancing performance. However, though you might try, it does not obviate the need to sleep.

Caffeine works to increase the number of adenosine receptors in the body, which makes users much more sensitive to adenosine. This results in tolerance or substantial reduction in its effectiveness as a stimulant. At the same time, cessation of caffeine leads to withdrawal symptoms.


Nicotine is found in the nightshade family of plants. As an anti-herbivore chemical, specifically for insects, it was widely used as a natural insecticide. The most common source of nicotine delivery is through tobacco in various forms  smoking, chewing and taken in the nose.

Nicotine inhaled while smoking a cigarette reaches the brain within seven seconds through the bloodstream after crossing the blood brain barrier. The amount of nicotine released in the body depends largely on the type of tobacco and the manner in which it is used. Chewing tobacco or holding tobacco between lip and gum or tobacco taken through the nose delivers a much greater amount of nicotine than cigarette smoking.

Cigarette smoking works as a stimulant as well as a relaxant. Nicotine delivered by smoking or chewing tobacco causes the liver to release glucose and the adrenal medulla to release epinephrine. In the brain, it stimulates the release of numerous chemical messengers including endorphin, the body’s natural analgesic. Apparently, smoking enhances concentration and memory and the analgesic effect of endorphin reduces pain.

The biggest negative effect of smoking or chewing tobacco is dependence and withdrawal. It is at least as addictive as cocaine and heroin. Nicotine dependence is actually the hardest addiction to break. The carcinogenic properties of nicotine have not been properly evaluated but those of cigarette smoking have been well researched. Nicotine does not appear in the group of carcinogens but it increases cholinergic activity, which can potentially lead to cancer. Smoking and the consequent release of carbon monoxide in cigarette smoke, on the other hand, is known to directly cause cancer.

Most surprising of all though, is that nicotine and caffeine have in common that they are natural pesticides! That such common items in our lives contain what could be effective pesticides is in my opinion quite fascinating.

(And by the way, you can check out our nicotine test by clicking on the link.  We do not sell or even think there exists a caffeine test at this time!).

- Anne Hamilton