Caffeine is the most popular and widely used drug in the world. It is a substance found in the leaves, seeds or fruit of a number of plant species, such as coffee and tea plants.
What are the plants and where do they grow?
Coffee beans are the seeds of the coffee plants Coffea arabica, Coffea canephora and Coffea liberica. After oil, coffee is the world's second most traded product, with the two largest export growers being Brazil and Colombia.
Tea is usually the leaves and buds of the tea plant (Camelia sinensis). The biggest producers of tea for the world market are India, China, Kenya and Sri Lanka.
The seed of the kola nut (Cola acuminata and Cola nitida) is consumed as a nut or as a tea, and is grown in West Africa.
The seed of the cacao pod (Theobroma cacao) is used to make cocoa and chocolate products. It grows in Brazil and West Africa.
The seed of the guarana plant (Paulinia cupana), which is grown in Brazil, is used in snack bars and beverages.
The effects of any drug (including caffeine) vary from person to person. How caffeine affects a person depends on many things including their size, weight and health and also whether the person is used to taking it, and the amount they have taken.
Regular caffeine users may have different experiences from people who consume caffeine products only occasionally.
There is no safe level of drug use. Use of any drug always carries some risk—even medications can produce unwanted side effects. It is important to be careful when taking any type of drug.
Caffeine takes 5–30 minutes to circulate in the body after it has been consumed. Its effects will continue as long as it is in the blood, which is usually around 12 hours. Some short-term effects of caffeine are:
Taking caffeine to stay awake
Some people consume drinks containing caffeine so that they can continue working or studying at night. However, the after-effect is that they will feel tired and lethargic the next day.
Serious injury or death from caffeine overdose can occur, but it is extremely rare. A person would have to consume 5–10 grams of caffeine (or 80 cups of strong coffee, one after the other) to suffer an overdose. Some effects of caffeine overdose include:
Moderate consumption (for example, up to 4 cups of coffee a day) of caffeine is unlikely to cause any long-term damage. However, heavier use of caffeine can have some serious effects including:
Pregnant women who consume high amounts of caffeine have increased risk of miscarriage, difficult birth and delivery of low-weight babies.
Other effects of using caffeine
Taking caffeine with other drugs
Combining stimulant drugs (like caffeine) with alcohol places the body under great stress and can mask some of the effects of alcohol. For example, if a person combines caffeinated energy drinks with alcohol they will still be affected by the alcohol but may not feel as relaxed or sleepy. They may feel more confident, take more risks and increase the chances of experiencing alcohol-related harm such as drinking too much or being injured in a fight or accident.
Pregnancy and breastfeeding
With regular use, over time a person's body can become used to functioning with caffeine present. They may become physically or psychologically dependent, or both, on caffeine.
A person who is dependent on caffeine is likely to suffer withdrawal symptoms if they try to stop using it.
A person who is dependent on caffeine is likely to suffer withdrawal symptoms within 24 hours of their last dose. Heavier users who consume more than 600 milligrams of caffeine a day may experience these symptoms within 6 hours.
Headache is the most common caffeine withdrawal symptom, but others include fatigue, sweating and muscle pains. Some users experience anxiety and tension when they give up caffeine. Withdrawal symptoms typically last around 36 hours, but very heavy caffeine users can experience withdrawal symptoms for longer.
Australia’s national drug policy is based on harm minimisation. Strategies to minimise harm include encouraging people to avoid using a drug, through to helping people to reduce the risk of harm if they do use a drug. It aims to reduce all types of drug-related harm to both the individual and the community.