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How Much Caffeine is Too Much?

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Pouring coffee into mug

No matter what your go-to is, coffee, tea, soda or energy drinks, it’s important to know how much caffeine is too much. Caffeine is a stimulant and approximately 85% of U.S. adults consume caffeine daily, mostly coming from coffee. 

The Food and Drug Administration considers up to 400 mg/day to be safe for healthy adults. However, some people may be more sensitive to caffeine so it’s important for you to be aware of how you react. 

Amount of caffeine in common beverages

  • Coffee (8 oz. brewed): ≈100 mg*
  • Espresso (shot): 77 mg*
  • Tea (8 oz.):
    • Black tea: 42 mg*
    • Green tea: 25 mg*
  • Soda (12 oz.): 40-55 mg
  • Energy drinks can vary greatly: ≈80-300 mg

*The caffeine content of coffee and tea can vary depending on the type of bean or tea leaf, harvest processing and extraction method.

Side effects of too much caffeine

  • Headaches 
  • Irritability 
  • Upset stomach 
  • Heartburn 
  • Anxiety 
  • Rapid heartbeat 
  • Nervousness 
  • Disrupted sleep 

Caffeine’s half-life on average is five hours, meaning you may still have some caffeine in your system if you drank a beverage containing caffeine within the last 10 hours. Because of that we recommend avoiding caffeine later in the day. 

The potential of overdosing on caffeine is rare, however; it is possible to consume too much. Toxic effects can occur with 1.2 g or higher. This typically occurs with caffeine pills or powders which are highly concentrated. 

If you decide to stop caffeine altogether, you may experience symptoms of withdrawals such as inability to concentrate, headache, agitation, depressed mood and fatigue. One way to help reduce these symptoms is to cut back on caffeine gradually. Try mixing decaf with your caffeinated beverage, add extra water to your coffee or tea or if you usually have two cups per day slowly work your way down to one. 

How to increase energy without caffeine

If you successfully reduce your caffeine intake, but still hit that afternoon slump, here are some ways to help increase your energy:

  • Take a short walk outside to enjoy the sunshine
  • Listen to upbeat music
  • Drink more water as fatigue can be a sign of dehydration
  • Eat regularly throughout the day; try not to go for more than three to four hours without eating

A Cooper Clinic registered dietitian nutritionist can help you develop a healthy eating plan to help boost energy all day long. 

If you’re concerned about any medical conditions and the amount of caffeine you’re consuming, consult your health care provider. 

Article provided by Hannah Janysek, MS, RDN, LD and Cooper Clinic Nutrition.