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HealthInfo Waitaha Canterbury



Caffeine is a chemical found in tea, coffee, chocolate, cocoa, kola nut and guarana. It can be an ingredient in energy drinks and cola-type soft drinks. It's also in some supplements and medications such as Panadol Extra.

Drinks like tea and coffee aren't just about the pick-me-up that caffeine gives some people, they're part of our culture and have an important role when we socialise together.

Caffeine's effect on the body

Caffeine stimulates the brain and central nervous system. Some people find caffeine helps them stay alert and improves their energy levels and concentration. Some people are more sensitive to caffeine and having too much can cause problems such as:

If you’re pregnant, having too much caffeine can increase your risk of having a miscarriage. It can also affect your baby’s growth and increase the risk of them having a low birth weight. Having a low birth weight can increase the risk of health problems later in life.

If you're breastfeeding, small amounts of caffeine can pass from your milk to your baby and build up in your baby over time. Having too much caffeine may make your baby irritable and cause sleeping issues.

Safe amounts of caffeine

Most adults can handle up to 400 mg of caffeine a day with no problems. 400 mg of caffeine is about:

If you're pregnant or breastfeeding, up to 200 mg of caffeine a day is safe for your unborn baby or breastfed infant.

Children can have the same problems with caffeine as adults but with much smaller amounts. It's best for children not to have much caffeine, especially from energy drinks and cola drinks that also have a lot of sugar.

Caffeine levels in drinks and food

The caffeine content of coffee and tea made at home and at cafés can vary. It depends on the type of coffee or tea, serving size and brewing method.

Drink or food

Average caffeine content (mg)

Espresso coffee (single shot)


Energy shots (90 ml)


Plunger coffee (1 cup)


Instant coffee (1 teaspoon)


Energy drinks (250 ml can)


Tea (1 cup)


Green tea (1 cup)


Cola drinks (330 ml can)


Chocolate bar (50 g)


Decaffeinated instant coffee (1 cup)


Tips for cutting down on caffeine

Cut back slowly. If you stop suddenly, you may trigger caffeine withdrawal symptoms. These can include headaches, tiredness, anxiety, difficulty concentrating and tremors.

Drink plenty of water. Not drinking enough water can make your caffeine withdrawal symptoms worse.

Have your last coffee by early afternoon so the caffeine can work itself through your system before bedtime.

Switch to decaf coffee, fruit tea or herbal tea. Some people find a cup of chamomile tea after dinner improves the quality of their sleep.

Find other ways to naturally boost your energy levels such as being physically active, getting enough sleep and eating well.

Written by HealthInfo clinical advisers. Last reviewed March 2022.


Page reference: 768868

Review key: HIHEI-34305