Nicotine acts as a stimulant and is typically taken by users to increase sensations of alertness, euphoria and reduce feelings of anxiety. These positive mood states accentuated by stimulants are followed by a recovery period, during this time negative moods are experienced. While smokers report feeling more alert and less stressed following the first cigarette of the day, between cigarettes they feel less focused and more irritable or anxious.

Regular smokers crave nicotine again within 20 minutes to an hour of smoking due to the rapid changes in mood, this is why a typical consumption pattern for someone who smokes is 10-30 cigarettes/day. As with other stimulant drugs, the body’s tolerance to nicotine builds quickly and regular tobacco users will require more nicotine to function day-to-day.

When there is a high amount of nicotine consumed acutely users can feel nauseous, dizzy and restless. Withdrawal symptoms from nicotine tend to be amplified symptoms of the feelings experienced between cigarettes and can include difficulty sleeping, concentrating, depressed mood and headaches.

Here are the most common effects, not everyone necessarily experiences all of them every time they consume the drug and other effects not listed might be felt. The likelihood of experiencing negative effects is far greater at high doses.

The effects are (from positive to negative):

Nicotine Overdose

A nicotine overdose (as a result of e.g. multiple nicotine lozenges) can be very harmful or fatal and requires immediate medical attention. The CDC states that about 50mg of nicotine is potentially deadly for the average adult ^{21 22}. The first signs of a nicotine overdose include nausea, vomiting, abdominal pain, fast heartbeat, high blood pressure, difficulty breathing, agitation and seizures. If the overdose is significantly over the recommended intake or left untreated, people can go onto develop serious issues like an abnormal or very slow heartbeat, muscle paralysis and coma.^{19 20}

How? How Much? When? For how Long?

As with any drug, the correct dose for you depends on factors such as weight, gender, metabolism, whether you have taken the drug recently or not, amongst many others.

Read our section on dosing and tolerance in ME for more information.

How you take it matters...

There are various ways of consuming nicotine, some more harmful than others.^{7 8}

Smoking is both the most popular and the most addictive method of consuming nicotine; delivering nicotine to the brain within seconds.

• Tobacco cigarettes: Cigarettes are made from dried and processed tobacco leaves, with some additives. As a result of combustion, tobacco smoke contains many carcinogens which are the main culprit for premature death.
• Cigars and Pipes: Most smokers only partly inhale the smoke, drawing it into the mouth but not the lungs, making cigars and pipes slightly less harmful than traditional cigarettes.
• Hookah: Non-filtered smoke is generated from a water-based smoking device and is flavoured and sweetened. Regular hookah smoking confers the same tobacco-associated health risks.
• Electronic cigarettes (e-cigs/vapes, including brands such as iQOS and Juul): Electronic, combustion-free devices delivering vaporised liquid, containing different percentages of nicotine. Preliminary findings suggest they are much less harmful than cigarettes, but can be more addictive due to the pleasant flavours added.

Other ways:

• Snus: tobacco placed on the gum for nicotine absorption. Safer alternative to smoking as it causes no lung damage, involves almost no carcinogens, and doesn’t affect those around you (i.e. second-hand smoking).
• Chewing tobacco (e.g. gutkha): Thought to be more dangerous than snus, and strongly linked to causing oral cancer.
• Snuffing tobacco (snuff): involves powdered tobacco inhaled up the nose. Although it confers a lower overall harm than cigarettes, it’s still linked to an increased risk of cancer of the nose, mouth and throat.
• Dissolvable tobacco (e.g. sprays, lozenges, chewing gums, nicotine patches): mostly used during smoking cessation as ‘nicotine replacement therapies’

How much?

It’s difficult to talk about nicotine dosage because it’s very person-dependent. Using nicotine is legal and, in most cases, a sociable act. This means that you get a significant range in how often or heavily people use it. The average cigarette contains 10-14mg of nicotine but you only actually inhale about 1-2mg¹⁸. The best way to understand nicotine dosing is by looking at how much nicotine a doctor will prescribe for some trying to quit smoking. The BNF advises 2mg, whenever cravings arise, for someone who smokes less than 20 cigarettes a day and 4mg for someone who smokes more than 20. Take this into account when purchasing nicotine products to avoid a nicotine overdose.

When do the effects kick in?

Onset: when inhaled, nicotine reaches the brain within 10-20 seconds¹⁴.

Duration: Nicotine has a half-life of 1-2 hrs, and so the effects wear off after a few hours¹⁵.

Onset of craving/withdrawal symptoms: Cravings, as well as withdrawal symptoms, can set in as soon as the last dose of nicotine is cleared from the body. This is about 4 hours after the last cigarette.

How often can I take it?

New reports have shown that smoking even 1 cigarette a day confers a significant increased risk for cardiovascular diseases, stroke and lung cancer.^{11 12} Social smoking can also confer significant risk for the same conditions and is advised to be kept at a minimum.¹²

If there’s one thing that can really be dangerous, it’s mixing drugs. We’ve compiled here the safety profiles of various mixes with nicotine (legal and illegal) but don’t swear by them. As with all matters drug-related, everyone is different and you can very easily experience an unexpected adverse reaction. If you’re taking medication, you need to be extremely wary when taking illegal drugs. Their interactions with prescribed medication are often poorly researched and you will definitely not be warned by your doctor about it.

• Using with other stimulants can cause an increased heart rate (amphetamines, caffeine, cocaine, MDMA)
• Combination with depressants can put a strain on the heart (alcohol, opioids, Benzos, Ketamine)
• Nicotine reduces the effectiveness of these medications: clozapine, fluvoxamine, olanzapine, tacrine, theophylline, caffeine¹⁶. This means that it’s incredibly important to be honest with your doctor about how much you use nicotine and to let them know if you’re planning to cut down or quit.
• Hormonal contraceptives are contraindicated in women ≥35 y.o. smoking ≥15 cigarettes/day due to increased compound risk of cardiovascular diseases¹⁶.

Smoking tobacco or consuming nicotine can lead to a rapid, insidious nicotine-dependence and quitting can be extremely difficult, with very high rates of relapse. The majority of smokers want to quit but find that they cannot. So, it’s important that you:

Head over to our ME section if you would like to know more about harm reduction.

Resist peer pressure: Most people are introduced to smoking by friends, often quite young. Remember that you can still go out for a “smoke break” with your friends without actually smoking. If you’re concerned about second-hand smoke or that you’ll be too tempted, skip these altogether.

Don’t start smoking: Smoking tobacco or vaping nicotine might look like a fun shared activity between friends, but it is highly addictive and comes with many serious health risks when done regularly.

Minimise consumption: Nicotine addiction can be a slippery slope, so minimise tobacco consumption as much as you can. A good way to keep smoking to a minimum is by refraining from buying your own pack of cigarettes (although your friends might hate you!). Additionally, try to use as little tobacco in joints with cannabis as possible, and resist the urge to smoke after drinking.

If addicted, quit as soon as possible: Quitting can be difficult but there are many options to get support. Talk to your pharmacist and doctor, and make sure to seek support from friends and family. Different methods work for different people, but some evidence suggests that stopping smoking completely and abruptly is the most effective. Many people fail on their first attempt but go on to kick the habit, so try to not get discouraged. Nicotine replacement therapies can help steadily wean you off of nicotine by slowly reducing your nicotine dependence.

Switch to less harmful nicotine-delivery products: E-cigarettes are safer alternatives to standard cigarettes, while snus and nicotine/patches/lozenges are even safer. It’s good to switch to smokeless tobacco as soon as possible to minimise the health risks.

If you think you may be addicted to nicotine, you can take the Fagerstrom test for nicotine dependence. You can also talk to your doctor to find out more about potential interventions and drug treatment services. Nicotine Anonymous is another good resource.

Secondhand smoke: Secondhand smoke is the combination of smoke from the burning end of a cigarette and the smoke exhaled by a smoker. The smoke burning from the end of a cigarette cigar actually contains more harmful substances than that inhaled by the smoker, as it does not pass through a filter.

Infants and children exposed regularly to secondhand smoke are exposed to a higher risk of permanent harms such as developing asthma, incomplete lung development and SIDS (Sudden Infant Death Syndrome). Children who grow up in a household with smokers are more likely to start using tobacco themselves.

Tobacco has been identified as the leading cause of preventable deaths by the World Health Organisation. It is responsible for over 7 million deaths per annum, 6 million of which are due to direct tobacco use and ~890000 resulting from second-hand smoke. Although nicotine is highly addictive, it does not contribute to the health risks listed below, and so smoke-free nicotine delivery methods are relatively safe when purchased from a reliable and safe retailer.

Addiction

Nicotine is extremely addictive, ranking as the 3rd most addictive drug after heroin & crack-cocaine. Almost 40% of people who start smoking become addicted, and there can be genetic vulnerabilities predisposing for nicotine dependence.^{4 5} Nicotine thus exposes smokers to the extremely harmful effects of tobacco smoking, which kills up to 50% of its users.⁹ Tobacco availability as well as the social context of smoking can contribute to high rates of exposure and fast transition to addiction. Alcohol has been shown to increase craving for tobacco in a dose-dependent way manner (i.e. nicotine cravings increase with the amount of alcohol consumed)¹³ and this can also speed up dependence.

Alarmingly, nicotine addiction causes permanent brain changes which are thought to increase the user’s sensitivity to the rewarding effects of other drugs, thus making them more vulnerable to addiction in general.

Withdrawal

Withdrawal is caused by your body craving nicotine and it can make it hard to quit because the symptoms can be unpleasant and hard to ignore. The effects of withdrawal aren’t life-threatening but it can take up to 3 months for your body to no longer crave nicotine.²⁵ Just remember that you’re making a vital change that will have an incredibly positive impact on your overall health.

The symptoms of withdrawal include: anxiety, headaches, depressed mood, difficulty concentrating, restlessness and irritability ²⁶. Withdrawal symptoms get worse with time until a normal balance is restored in the brain after abstinence. Slowly tapering down your nicotine requirements is an effective way to quit smoking because it can reduce withdrawal symptoms and reduce the likelihood of relapse.

Cancer

Since a causative link was first identified between smoking tobacco and lung cancer in the 1920s, extended research has universally confirmed that smoking tobacco significantly increases the risk of certain types of cancer⁹: It confers a **20-fold** increased risk of lung cancer and an increased risk of oral cancer. This is mainly due to the 69 carcinogens found in tobacco smoke (including arsenic, benzene and lead), but additives commonly found in packet cigarettes are thought to contribute to this as well.¹⁰ Now it’s accepted that tobacco use can cause at least 15 different cancers.

Other health risks

There are various severe and fatal health conditions which can result from first-hand or second-hand smoking, listed below:

• Increased risk of lung diseases (e.g. chronic bronchitis, emphysema, asthma)
• Risk of heart problems, CVD and stroke: Carbon monoxide, which is produced via combustion, can damage the heart and blood vessels leading to blood vessel constriction and acute hypertension
• Risk of diabetes
• Osteoporosis
• Foetal injury: this can happen if the mother smokes during pregnancy
• Sudden Infant Death Syndrome: can result from second-hand smoking

Nicotine, although not directly linked to health problems such as cancer, has associated side effects which can be harmful. Nicotine can cause the following:

• Atherosclerosis
• Peptic ulcers
• Increased risk of stroke
• During pregnancy, it could confer risk for obesity and type 2 diabetes for the foetus

Dangerous conditions

If you have or have had cardiovascular problems, high blood-pressure, asthma, lung problems, or cancer it is not recommended to smoke as this will increase the risk of these conditions becoming worse or reappearing.

Schizophrenia

People affected by schizophrenia are thought to be more susceptible to nicotine addiction, and smoking constitutes the main reason for premature death among this group. Thus, if you have a family history or experiences of psychosis it’s advised to never start smoking tobacco.

In the long-term...

Smoking severely compromises quality of life in the long term, as it greatly reduces physical fitness and can in many cases cause erectile dysfunction in men. Fertility rates are decreased as a result of smoking in both sexes. It can also produce changes in physical appearance such as premature ageing, yellowing or rotting teeth and fingernails and can give rise to a foul breath. Furthermore, smoking can be very expensive and long-term users end up spending a significant portion of income to keep up their habit.

EUROPE: In most countries, the legal age for possession and public smoking is 16-18, while the legal age to buy tobacco is 18.

Exceptions to this:

• Liechtenstein (≥16 for both)
• Kosovo (No min. age for both)

AMERICA: Regional legislation varies greatly, with minimum age being 16, 17, 18, 19, and 21 in different states (For detailed information visit https://en.wikipedia.org/wiki/Smoking\_age)

ASIA AND AUSTRALIA: Most countries have either no legal age or a minimum age of 18 for possession, and a minimum age of 18 for purchasing tobacco.

Exceptions to this:

• Bhutan: Sale, cultivation and production of tobacco are illegal
• Bangladesh (≥16 for both)
• Iraq (No min. age for both)
• Japan (≥20 for both)
• Mongolia (≥21 for both)
• North Korea (≥17 for buying)
• Singapore (≥19 for both)
• South Korea (≥19 for possession, ≥20 for buying)
• Sri Lanka (≥21 for buying)
• Turkmenistan: Tobacco sales are illegal
• Yemen (No min. age for both)
• Samoa (≥21 for both)
• Tokelau (≥16 for both)

AFRICA: Most countries have no legal age for possession, but a minimum age of 18 for purchasing tobacco.

Exceptions to this:

• Uganda (≥21 for buying)
• Algeria (≥19 for buying)
• Djibouti (≥16 for buying)
• São Tomé and Principe (≥16 for buying)
• Zambia (≥16 for buying)
• Cameroon (No min. age for both)
• Cape Verde (No min. age for both)
• Central African Republic (No min. age for both)
• Gambia (No min. age for both)
• Guinea-Bissau (No min. age for both)
• Lesotho (No min. age for both)
• Malawi (No min. age for both)
• Morocco (No min. age for both)
• Somalia (No min. age for both)
• South Sudan (No min. age for both)
• Tunisia (No min. age for both)

Importantly, many of these countries, such as Australia and Russia, have smoking bans in place, prohibiting indoor smoking. You can read more about specific smoking bans here https://en.wikipedia.org/wiki/List\of\smoking\_bans.

Newer bans have been placed in some countries, prohibiting electronic cigarettes in some countries either altogether or if containing nicotine. These are as follows:

• Argentina: Banned
• Australia: Permitted, if without nicotine
• Austria: Banned
• Belgium: Permitted, if without nicotine
• Brazil: Banned
• Brunei: Banned (fine of $10,000 can be imposed)
• Colombia: Banned
• Denmark: Permitted, if without nicotine
• Thailand: Possession of e-cigarettes can be punishable by up to 10 years in prison.