Cigarettes are addictive there is no doubt about it, but are substances added to ‎make them more addictive? And if ingredients are added to only “improve the ‎taste”, do they in actual fact only improve the taste?‎

The main ingredient in cigarettes is tobacco – a plant that contains, among other things, a relatively high concentration of a chemical called nicotine, which is the active and addictive compound in cigarettes. But it is a mistake to consider cigarettes a ‘natural’ product. Since the 1950s, the tobacco companies, especially in the U.S., initiated countless scientific studies that have led to many changes in cigarettes, in order to increase their biological and pharmacological effect. In recent years, as a result of legislative changes in the U.S. and claims filed against the cigarette manufacturers, companies have been forced to publish secret documents of the studies on smoking carried out over the years. They were also forced to disclose the ingredients that are added to cigarettes.

Here we take a look at Philip Morris USA, manufacturer of Marlboro cigarettes, L & M, Parliament, etc. Below is a list of materials included in the tobacco mixture of Marlboro cigarettes (ingredients listed also represent other cigarettes):

Ingredients of Marlboro cigarettes | Screenshot from the website of Philip Morris USA

And R.J. Reynolds’ cigarettes, a competitor tobacco company, which manufactures, among other brands, Winston, Camel, Pall-Mall and Lucky Strike, contain the exact same components. This is the list of ingredients in Camel Blue cigarettes:

Ingredients in Camel Blue cigarettes | Screenshot from the website of the tobacco company R.J. Reynolds

The tobacco companies argue that the components are designed to enhance the taste of the cigarette, reviewing the list of ingredients shows that many of the components that are added act on the human body or on the nicotine itself to strengthen its effect, as explained in detail below. Is this a coincidence? Judge for yourself:

Sugar mixture – Beyond their stated effect on the taste, helping to mask nicotine’s bitterness, heated and burnt sugars emit a substance called acetaldehyde and cigarette smoke is indeed rich in acetaldehyde. Studies show that when acetaldehyde is absorbed with nicotine it reaches the brain, and has a more powerful (synergistic) effect – i.e., one substance increases the activity of other, so when combined, these substances’ effect is more powerful than just the sum of their effects alone:

Controlled studies in rats (using an established animal model for tobacco addiction) showed a mixture of nicotine with a small amount of acetaldehyde causes a much stronger addiction than nicotine by itself; the rats consumed more nicotine compared to when they were given just ‘pure’ nicotine. Furthermore, the effect is actually strongest in young animals. The most plausible mechanism of action at work here is based on inhibition of the enzyme called monoamine-oxidase (MAO), active in brain nerve cells, where it is responsible for breaking down neurotransmitters. The result is a prolonged activity of pleasurable substances that are released in the brain under the influence of nicotine, such as dopamine and serotonin.

Source no. 1: Acetaldehyde enhances acquisition of nicotine self-administration in adolescent rats.

Source no. 2: European Commission, Health and Consumer protection – Tobacco Additives.

Source no. 3: Abuse potential of non-nicotine tobacco smoke components: acetaldehyde, nornicotine, cotinine, and anabasine. Sales, Nicotine and Acetaldehyde Relationships. 

Source no. 4: From the documents forcibly published by studies done by Philip Morris, titled “Behavioral Pharmacology Annual Report – 1983” that evaluates the optimal relationship for the ratio of nicotine to acetaldehyde in cigarettes, according to sales.

Licorice extract – A herb with a typical flavor which also affects cigarette taste. But one of the plant’s main components is a substance called Glycyrrhizin – which also acts as a bronchodilator, i.e., a chemical that expands the tubes in the lungs, allowing more smoke to penetrate into the lungs and beyond, and therefore increasing the effect of smoking.


The trachea split to form the two lungs. On the bottom are the bronchi | Illustration: Wikipedia

The importance of licorice and the extent of its use in modern cigarettes is demonstrated by the fact that it accounts for 1-4% of a cigarette’s weight; and 90% of the world's licorice is used by the cigarette industry.


Source no. 1: Cigarettes: Some things you probably didn't know were in there (including licorice)
Source no. 2: Seeing Through the Smoke -- The Secrets In a Cigarette
Source no. 3: Toxicologic evaluation of licorice extract as a cigarette ingredient

Di-ammonium phosphate and ammonium hydroxide – These two chemicals release ammonia gas [NH3(g)]. Ammonium phosphate [(NH4)2HPO4(s)] releases ammonia when heated, according to the following reaction:

(NH4)2HPO4(s) → NH3(g) + NH4H2PO4(s)

Ammonium hydroxide is simply a solution of ammonia gas in water. Why release ammonia into the smoke mixture? Since ammonia is chemically a base, it helps release other bases into their pure state.

An explanation is needed here: Nicotine, like other natural substances (e.g., cocaine) is a base. Bases tend to react with acids to form salts. Indeed, in dry tobacco the nicotine composition includes acid as “nicotinic acid”. When nicotine is in its salt form, its absorption into the body is more difficult. The ammonia replaces nicotine in the salt compound, thereby releasing it and thus allowing it to be absorbed and act more strongly and quickly.

The faster a drug affects the brain, the stronger the dependence developed on it. This is exactly the difference between crack and cocaine – the drug is one and the same, but the former contains baking soda (a base) that causes it to be much more powerful. By the same token, adding ammonia to tobacco changes the nicotine to “crack” nicotine, whose power is much greater than normal nicotine.

Source: Brand differences of freebase nicotine delivery in cigarette smoke: the view of the tobacco industry documents.

Cocoa and cocoa products – Even this seemingly innocent material, apparently designed to improve taste, has a pharmacological chemical that affects the lungs: Theobromine.

The chemical structure of Theobromine, which relaxes the bronchi and reduces cough | Illustration: Wikipedia 

Theobromine has a dual effect on the human body – it expands the bronchial tubes, just like the material in licorice (in fact, this is its medicinal use), and can also act as a powerful cough suppressant (a 2004 study found that it was stronger than codeine – the active ingredient in cough syrups) by inhibiting the activity of the vagus nerve. In other words, adding cocoa to cigarettes suppresses the body's natural response to smoke – coughing – thus enabling the smoker to feel healthy and hold the smoke for longer without irritation or the need to cough. Indirectly, this also increases the effect of nicotine on the body, by increasing the feeling of respiratory health, so that one can smoke for longer and thus increase the absorption of nicotine from the lungs into the blood.

Source: Theobromine inhibits sensory nerve activation and cough.

Natural and artificial flavors – Tobacco companies do not publish individual components whose concentration in a cigarette is less than 0.1%, but instead, collectively mark all other ingredients they add under this name. This includes a long list of chemicals, and, as we have seen, it is likely that the activity of some are not so innocent and do not only affect taste or smell, but also have a pharmacological activity on the body: A book recently published in the United States, based on hundreds of documents from US tobacco companies that were forcibly published, found that in addition to all of the above, they add a substance called levulinic acid, which increases the binding of nicotine to receptors in the brain.

Thus, tobacco cigarettes contain a mixture of many substances, in addition to tobacco, that operate on many aspects to strengthen the biological addictive effects of cigarettes. They enhance the activity of nicotine, increase its concentration, shorten the time it takes for it to become available, expand airways, and inhibit the cough reflex. These ingredients were added to the mix after a long process and years of research and scientific development initiated by the cigarette companies.

Beagles used in research for developing a new type of cigarette. The photograph shocked the nation when it was first published in 1975 | Photograph by Mary Beith, Bournemouth Times

In other words, cigarettes are an adapted (in the negative sense of the word) product that has been developed to be stronger and more addictive than in its natural state through exploiting research tools and scientific knowledge. New studies show that 10-25% of smokers will develop symptoms of cigarette addiction after smoking even just one cigarette.

Given the numerous health dangers of smoking and the high chances of developing an addiction, which the tobacco companies have apparently acted to enhance through the means mentioned above, it is highly recommended to not try smoking - even once.