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Caffeine - How much is too much?

Caffeine, found in numerous beverages and even food products, helps many of us to keep us awake throughout the day. Approximately 81% of the US population consumes caffeine on a regular basis.

What is Caffeine?

Caffeine occurs naturally in coffee beans, tea leaves, cocoa beans, kola nuts and added to many foods and beverages such as caffeinated soda and energy drinks. Caffeine stimulates the central nervous system (CNS) and in moderation results in alertness, raising energy levels and heart rate. Thus, it is the most commonly consumed psychoactive substance worldwide.

How is Caffeine Consumed Around the World?

Here's an overall list (huge variations between the countries) of what are the leading caffeinated drinks around the continents:

  • Africa: Tea (black) and carbonated soda (non-cola-type)

  • Asia and the Pacific: Tea (black, green and other) and carbonated soda (cola-type)

  • Europe: Coffee and carbonated soft drinks (cola-type) Coffee drinkers: Netherlands, Finland, Sweden Tea drinkers: Ireland, Turkey, UK, Latvia

  • Latin America and Caribbean: Carbonated soda (mostly cola-type) and coffee (mostly fresh-brewed)

  • North America: Coffee (Fresh-brewed) and carbonated sodas


In general, up to 400 mg caffeine/day is considered to be safe for most healthy adults which is equivalent to:

  • 5 shots of espresso

  • 1 Starbucks Venti brewed coffee

  • 2.5 x 500 mL Monster Energy Drinks

  • 5 x 250 mL Red Bulls

  • 12 x 350 mL Cokes

Other recommendations

  • Indonesia and New Zealand: <250-300 mg/day for pregnant women

  • Albania, Belgium, Denmark, Ireland, Latvia and Romania: <200 - 300 mg/day for pregnant and lactating women

  • Canada and America: <300 mg/day for pregnant and breastfeeding women

  • New Zealand: <300 mg/day for older people due to bone health

  • Portugal: <300 mg/day for healthy people

  • Netherlands: recommends daily consumption of 3 cups of green/black tea

The guidelines cannot be applied to everyone as people can have different sensitivities or reactions to caffeine based on age, body weight, medical history and tolerance.


As children and adolescents are smaller than adults, a lower amount can lead to side effects such as headaches, insomnia, jitteriness and increased blood pressure.

Another concern may not be the caffeine content but rather the empty calories and high sugar content that often comes along with the caffeinated drink. For instance, a single can of coke alone provides 140 kcal and 39 g of sugar. A Starbucks grande caramel frappuccino coffee has a whopping 420 kcal and 66 g of sugar.

The European Food Safety Authority (EFSA) states that 3 mg of caffeine per kg of body weight is safe for children and adolescents.

  • US: no guidelines

  • Canada: <2.5 mg/kg body weight day (equivalent to 1 can of coke)

Medical History

Those with heart conditions, oversensitive to caffeine and pregnant/nursing women may want to limit their caffeine consumption as it can have adverse health implications.

High doses of caffeine can temporarily increase your heart rate and blood pressure. However, the link between caffeine and heart conditions remains controversial and it has been suggested that moderate consumption is not linked to cardiovascular disease (CVD).

Some evidence suggests that higher caffeine intake may be associated with a higher risk of pregnancy loss and lower birth weight baby. However, a review found that moderate to high caffeine intake does not increase the risk of congenital malformations, miscarriage or growth retardation.

Small amounts of caffeine can be passed through breast milk and large amounts can make babies restless so it has been recommended to limit caffeine intake to below 200 mg/day. However, a study has shown that it has not affected the sleep patterns in 3 months old babies.


Some people are more sensitive to caffeine and even in small quantities may result in unwanted side effects. Those who do not consume caffeine regularly tend to be more sensitive.

So how much do we consume (EU)?

According to the European Food Safety Authority (EFSA), it has been revealed that caffeine consumption increases with age and the highest caffeine intake was seen in the elderly (75+ years).

Possible Benefits?

It may be beneficial to consume caffeine in moderate amounts as it has been linked to a reduced risk of several chronic diseases.

People who drink coffee regularly have a reduced risk of developing Alzheimer's and dementia. In this observational study, it has found that adults aged > 65 who consumed an average of 261 mg caffeine per day compared to those who consumed an average of 64 mg per day reported fewer dementia symptoms. However, results may be due to antioxidants or other nutrients from coffee rather than caffeine alone.

Participants who increased their coffee consumption by more than one cup per day had a 1% lower risk of developing type 2 diabetes. Conversely, those who reduced their consumption by more than one cup had a 17% higher chance for developing type 2 diabetes. However, more research is needed before suggesting that caffeine consumption reduces your type 2 diabetes risk.

Studies have demonstrated that caffeine increases memory and reasoning in sleep-deprived individuals. Additionally, those who consumed at least three cups of coffee per day (around 300 mg caffeine) is linked to a slower cognitive decline in women especially at higher ages.

Possible side effects?

Some people may be more sensitive to caffeine and this could cause unpleasant side effects such as:

  • Migraine headache

  • Insomnia

  • Nervousness

  • Irritability

  • Restlessness

  • Stomach upset

  • Fast heartbeat

  • Muscle tremors

Overdose on caffeine or also known as "caffeinism" typically reaching to a dose of 1 - 1.5 g per day can lead to:

Death is possible especially when taking caffeine products in very concentrated or pure forms. Caffeine powder can provide approximated 200 mg per 1/32 tsp and caffeine pills average between 100 to 200 mg per tablet. It can be very easy to overdo it and hence, it should be used in moderation.

Regular high consumption can lead to caffeine withdrawal as well:

  • Headache

  • Fatigue

  • Anxiety

  • Irritability

  • Drowsiness

It is recommended that individuals gradually reduce their consumption to avoid symptoms appearing.

Amount of Caffeine in Drinks

This table shows the typical caffeine content in popular drinks.

*Amount based on 400 mg/day

Starbucks nutritional information here. Costa and Caffe Nero have not disclosed the amount of caffeine in their drinks on their website. Values from Caffeine Informer. However, Costa drinks contain the highest caffeine content amongst all brands.

Concentrations in coffee beverages depend on the manufacturing process, the type of coffee beans used, and the type of preparation (e.g. drip coffee, espresso).

List of various brands for coffees, teas, soft drinks and energy drinks

The levels found in cocoa-based beverages depend on the amount and type of cocoa present in different brands.

Amount of Caffeine in Food

Amount of Caffeine in Other Products

Caffeine is a common ingredient in medications such as pain relievers to treat headaches and migraines, weight loss supplements and premenstrual syndrome (PMS) pills.



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