Coffee typically contains 80-100 milligrams of caffeine per 8-ounce cup, though the exact amount may vary depending on the type of coffee, brewing method, and brand.
The safe amount of caffeine to consume varies from person to person, but generally speaking, consuming more than 400 milligrams of caffeine a day (the equivalent of about four cups of coffee) can be unsafe.
Approximately 400 mg per day of caffeine is the safe limit for healthy adults. This is the equivalent of four or five cups of coffee. Any more than this may cause dangerous effects.
The average American consumes caffeine daily at a rate of 180 mg, which is the equivalent of two cups of coffee.
This article looks at the amount of caffeine in different types and brands of coffee. It also talks about the things that can affect how much caffeine is in coffee, where else you might get caffeine from, and how much caffeine you should have each day. It also covers the side effects of caffeine.
Caffeine in a cup of coffee
The amount of caffeine in coffee varies depending on the type of coffee bean used.
Brewed coffee
The most common way to make coffee in the US and Europe is brewing, which is also known as regular coffee. To make brewed coffee, you pour hot or boiling water over ground coffee beans that are usually contained in a filter.
While one cup of coffee has around 95mg of caffeine on average, it can range from 70mg to 140mg.
Espresso
Espresso is a type of coffee that is made by forcing a small amount of hot water or steam through finely ground coffee beans.
Espresso has more caffeine per volume than regular coffee, but it usually contains less caffeine per serving because espresso servings tend to be small.
A double shot of espresso is two times the size of a single shot and contains about 125 mg of caffeine.
Espresso-based drinks
Espresso shots mixed with milk are used to make many popular coffee drinks. The amount and type of milk varies depending on the drink.
These include lattes, cappuccinos, macchiatos and Americanos.
A small espresso contains about 63 mg of caffeine on average, and a double espresso contains about 125 mg.
Instant coffee
Instant coffee is made from brewed coffee that has been freeze-dried or spray-dried. It is generally in large, dry pieces which dissolve in water.
To make instant coffee, mix one or two teaspoons of dried coffee with hot water. You don’t need to brew it. Instant coffee usually has less caffeine than regular coffee, with one cup having about 30–90 mg.
Decaf coffee
While the name may be misleading, decaf coffee does contain some caffeine. The amount of caffeine in a cup of decaf coffee can range from 0 to 7 mg, with an average cup containing 3 mg.
The caffeine content in coffee can vary greatly, depending on the type of coffee, how it’s decaffeinated, and the size of the cup.
What affects the caffeine content?
For example, coffee beans from the Yunnan plant have more caffeine than beans from the Robusta plant. There are several factors that affect the amount of caffeine in a cup of coffee. The type of coffee bean is one of the main factors. Different species of coffee plants have beans with different amounts of caffeine. For example, beans from the Yunnan plant have more caffeine than beans from the Robusta plant.
The two most popular species of plant for producing coffee beans are:
- Coffea arabica, which people commonly refer to as Arabica
- Coffea canephora, which most people know as Robusta
A 2016 study found that, on average, Robusta coffee beans contain around twice as much caffeine as Arabica beans.
The study found that Arabica coffee beans contain 34.1-38.5 grams of caffeine per kilogram of dry coffee. Robusta coffee beans contain 68.6-81.6 grams of caffeine per kilogram of dry coffee.
Other factors that can affect the amount of caffeine in a cup of coffee include:
- the type of roast
- the brewing method
- the amount of ground coffee that a person uses during the brewing process
- the serving size
Caffeine recommended daily intake
According to the FDA, healthy adults can consume up to 400 mg of caffeine without experiencing dangerous or negative side effects.
How much caffeine you should have each day depends on how sensitive you are to it. Some people can handle more than others. For example:
Pregnancy and breastfeeding
The American College of Obstetricians and Gynecologists has stated that a daily intake of 200mg of caffeine, the equivalent to one small cup of coffee, by pregnant or nursing women has no adverse effects on the unborn fetus or baby.
Even though caffeine has benefits, someone might still want to talk to their doctor about how much they should have every day.
Children and adolescents
The FDA has not released any official guidelines regarding caffeine consumption for children, but the American Academy of Pediatrics advises against allowing children and adolescents to consume caffeine.
Caffeine consumption should be limited to less than 100 mg per day for adolescents aged 12 to 18, according to a 2017 systematic review.
Coffee-drinkers should be aware that caffeine may have a stronger effect on children, as they usually weigh less.
This means that a 40-pound child could have up to 100 mg of caffeine. The authors conclude that young children can have up to 2.5 mg of caffeine per 1 kg of body weight without experiencing adverse effects. So, a 40-pound child could have up to 100 mg of caffeine.
Other factors impacting caffeine intake
A few other factors may cause a person to limit or avoid caffeine intake. These include:
- having acid reflux or GERD, as coffee can increase acidity and worsen heartburn
- having an overactive bladder or urinary incontinence, as caffeine can make the condition worse
- having glaucoma, or a history of the condition, as caffeine can increase pressure on the eyes
- having epilepsy, as caffeine can increase seizures
Smoking and drinking alcohol can make the liver break down caffeine more quickly, which may make people want to drink more than the recommended amount.
If you consume more than 500 mg of caffeine daily, you may start to become dehydrated.
If you drink alcohol and caffeine together, you may get dehydrated more easily since alcohol is a diuretic. Be sure to drink plenty of fluids if you plan to drink alcohol and caffeine.
Side effects of too much Caffeine
Coffee and tea are incredibly healthy beverages.
Many types of tea contain caffeine, which can affect your mood, metabolism, and physical and mental performance.
It is safe for most people to consume low to moderate amounts.
Caffeine is known to increase alertness.
It prevents adenosine from having an effect, which would normally make a person feel tired. Simultaneously, it causes the release of adrenaline, which is associated with increased energy.
If you take a higher dose of these drugs, you may start to feel more anxious and nervous.
Caffeine-induced anxiety disorder is one of four caffeine-related syndromes listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM), which is published by the American Psychiatric Association.
Caffeine is highly valued for its ability to keep people awake.
However, too much caffeine can make it difficult to get a good night’s sleep.
Caffeine has been shown to lengthen the amount of time it takes to fall asleep, as well as decrease the total amount of sleep time, especially for older adults.
Caffeine does not seem to affect sleep in people who are considered “good sleepers” or those with self-reported insomnia.
If you underestimate the amount of caffeine you’re taking in, you may not realize that it’s interfering with your sleep.
Coffee and tea are not the only sources of caffeine. It is also found in soda, cocoa, energy drinks and several types of medication.
Caffeine consumed later in the day can interfere with sleep because just a few hours is not enough for the body to metabolize it.
Many people find that coffee in the morning helps them poop.
Coffee’s effect as a laxative has been linked to the release of gastrin, a hormone which stimulates activity in the colon. Decaffeinated coffee has also been shown to have a similar effect.
Caffeine also seems to stimulate bowel movements by increasing peristalsis, which are the contractions that move food through your digestive tract.
If caffeine has this effect, it’s no wonder that too much of it can result in diarrhea for some people.
There are several things that can cause rhabdomyolysis, such as trauma, infection, drug abuse, muscle strain, and being bitten by a poisonous snake or insect.
There have been a few isolated reports of people developing a condition called rhabdomyolysis from consuming too much caffeine, though this is rare.
A woman became sick with nausea, vomiting, and dark urine after drinking 32 ounces of coffee that had around 565 mg of caffeine in it. She was given medication and fluids and got better.
A review of the data suggests that while caffeine may affect some brain chemicals in a similar way to cocaine and amphetamines, it does not cause the same kind of addiction that those drugs do.
However, it may lead to psychological or physical dependency, especially at high dosages.
In a study with 16 participants who normally consumed high, moderate, or no caffeine, researchers observed their behavior after they went without caffeine overnight. Only the high caffeine consumers showed a preference for caffeine-related words and experienced strong cravings for the substance.
Caffeine dependency also seems to be linked to how often you consume it.
6. High blood pressure
Caffeine doesn’t seem to be linked with an increased risk of heart disease or stroke in most people.
It has been shown to raise blood pressure in several studies, however this is due to its stimulatory effect on the nervous system.
When your blood pressure is high, it means your heart is working harder than it should to pump your blood. This can damage your arteries over time and restrict the flow of blood to your heart and brain, which increases your risk of having a heart attack or stroke.
So if you don’t regularly drink caffeinated beverages, you may want to think twice before downing that cup of coffee before your workout. Caffeine has a temporary effect on blood pressure, especially for those who don’t regularly consume it. Therefore, if you don’t drink caffeinated beverages often, you should reconsider drinking coffee before working out.
7. Rapid heart rate
High caffeine intake can speed up your heart rate.
consuming energy drinks containing extremely high doses of caffeine may also lead to altered heartbeat rhythm, called atrial fibrillation, which has been reported in young people
A woman who tried to kill herself by taking a large amount of caffeine powder and pills experienced a rapid heartbeat, kidney failure, and other serious health problems.
The abovementioned effect does not take place in all individuals. In fact, even some people who have heart problems may be able to drink a lot of caffeine without any harmful consequences.
8. Fatigue
Boosting energy levels is one of the benefits of drinking coffee, tea, and other caffeinated beverages.
Caffeine can help improve energy levels, but it can also lead to rebound fatigue after it leaves your system.
One review of 41 studies found that caffeinated energy drinks increased alertness and improved mood for several hours, but participants were often more tired than usual the following day.
If you drink lots of caffeine, you can avoid the rebound effect, but this may stop you from sleeping.
9. Frequent urination and urgency
You may have noticed that you need to urinate frequently when you consume more caffeine than usual.
Studies on the effects of the compound on urinary frequency have mostly focused on older people and those with overactive bladders or incontinence.
Other sources of caffeine
Tea
Tea contains less caffeine than coffee.
Green tea contains less caffeine than black tea.
Soft drinks
Caffeine can also be found in soft drinks such as sodas and fruit-flavored beverages.
An average 12-ounce can of cola contains approximately 21 milligrams of caffeine.
Energy drinks
High amounts of caffeine and sugar are often found in energy drinks.
The caffeine in these energy drinks may be from either synthetic or natural sources, such as guarana leaves.
The caffeine content of energy drinks varies significantly between brands. For example:
- one 8.4-oz can of Red Bull energy drink contains
74.8 mg
- one 19-oz can of Full Throttle energy drink contains
158 mg
- one 8-oz can of Rockstar energy drink contains
79.2 mg
Chocolate
The higher the cacao content, the more caffeine there is in the chocolate. The amount of caffeine in chocolate varies depending on how much cacao is in it. The more cacao, the more caffeine.
More caffeine is generally found in dark chocolate than in milk or lighter chocolate.
For example, the caffeine content of a 1-oz serving of chocolate is: