Caffeine: Facts, Contents & Side Effects

picture of coffee caffeine


Caffeine is a bitter substance found in coffee, tea, soft drinks, chocolate, kola nuts, and certain medicines. It has many effects on the body’s metabolism, including stimulating the central nervous system. This can make you more alert and give you a boost of energy.

For most people, the amount of caffeine in two to four cups of coffee a day is not harmful. However, too much caffeine can cause problems. It can

  • Make you jittery and shaky
  • Make it hard to fall asleep or stay asleep
  • Cause headaches or dizziness
  • Make your heart beat faster or cause abnormal heart rhythms
  • Cause dehydration
  • Make you dependent on it so you need to take more of it. If you stop using caffeine, you could get withdrawal symptoms.

Some people are more sensitive to the effects of caffeine than others. They should limit their use of caffeine. So should pregnant and nursing women. Certain drugs and supplements may interact with caffeine. If you have questions about whether caffeine is safe for you, talk with your health care provider.

Caffeine facts

  • Caffeine is a stimulant obtained from over 60 different types of plants worldwide.
  • The scientific name for caffeine is 1,3,7-trimethylxanthine.
  • Caffeine is considered to be the most commonly used psychoactive drug in the world.
  • Coffee, soda, and tea are the most common sources of caffeine in the American diet.
  • Discontinuation of regular caffeine use may produce withdrawal symptoms.
  • The effects of caffeine persist for about three hours or less.
  • Caffeine is found in some combination medications and weight control products.
  • The American Medical Association and US Food and Drug Administration consider a moderate intake of caffeine to be “generally recognized as safe.”

Caffeine Side Effects

Caffeine can lead to:

  • A fast heart rate
  • Anxiety
  • Depression
  • Difficulty sleeping
  • Nausea
  • Restlessness
  • Tremors
  • Urinating more often
  • Vomiting

Stopping caffeine suddenly may cause withdrawal symptoms. These may include:

  • Drowsiness
  • Headaches
  • Irritability
  • Nausea
  • Vomiting

There has been much research on the health effects of caffeine.

  • Large amounts of caffeine may stop the absorption of calcium and lead to thinning bones (osteoporosis).
  • Caffeine may lead to painful, lumpy breasts (fibrocystic disease).

Caffeine may harm a child’s nutrition if drinks with caffeine replace healthy drinks such as milk. Caffeine cuts down on appetite so a child who consumes caffeine may eat less. The United States has not developed guidelines for caffeine intake by children.

Is caffeine safe during pregnancy?

There is no disputing the importance of proper nutrition during pregnancy. There is some dispute about the safety of caffeine during this time. One concern is that caffeine may lead to miscarriages. In a study following 431 pregnant women, no relationship between caffeine consumption up to 300 mg/day and adverse pregnancy outcomes was found. Another study examined the relationship between caffeine consumption and spontaneous abortions in over 5,000 women and found no association. A recent study found that caffeine can reach the follicular fluid of the ovaries. It also found that an increase in coffee consumption was associated with an increased number of aborted pregnancies.

On the other side, research has also shown no clear relationship between caffeine intake and fertility and birth defects. Even with this evidence, everyone agrees that there is a limit for how much caffeine can be consumed during pregnancy. The majority of the subjects in the studies were consuming small to moderate amounts of caffeine. It is difficult to accurately test the effects of very high intakes of caffeine without risking the health of the mother and child.. The American College of Obstetricians and Gynecologists recommends a caffeine limit of the equivalent of one to two cups of coffee per day during pregnancy. 

Caffeine Content


Serving Size

Caffeine (mg)

Dunkin’ Donuts Coffee with Turbo Shot large, 20 fl. oz. 436
Starbucks Coffee venti, 20 fl. oz. 415
Starbucks Coffee grande, 16 fl. oz. 330
Panera Frozen Mocha 16.5 fl. oz. 267
Starbucks Coffee tall, 12 fl. oz. 260
Starbucks Caffè Americano grande, 16 fl. oz. 225
Panera Coffee regular, 16.8 fl. oz. 189
Starbucks Espresso Frappuccino venti, 24 fl. oz. 185
Dunkin’ Donuts Coffee medium, 14 fl. oz. 178
Starbucks Caffè Mocha grande, 16 fl. oz. 175
Starbucks Iced Coffee grande, 16 fl. oz. 165
Maxwell House Ground Coffee—100% Colombian, Dark Roast, Master Blend, or Original Roast 2 Tbs., makes 12 fl. oz. 100-160
Dunkin’ Donuts Cappuccino large, 20 fl. oz. 151
Starbucks—Caffè Latte, Cappuccino, or Caramel Macchiato grande, 16 fl. oz. 150
Starbucks Espresso doppio, 2 fl. oz. 150
Keurig Coffee K-Cup, all varieties 1 cup, makes 8 fl. oz. 75-150
Folgers Classic Roast Instant Coffee 2 tsp., makes 12 fl. oz. 148
Starbucks Doubleshot Energy Coffee, can 15 fl. oz. 146
Starbucks Mocha Frappuccino venti, 24 fl. oz. 140
Starbucks VIA House Blend Instant Coffee 1 packet, makes 8 fl. oz. 135
McDonald’s Coffee large, 16 fl. oz. 133
Maxwell House International Café, all flavors 2⅔ Tbs., makes 12-16 fl. oz. 40-130
Seattle’s Best Coffee—Iced Latte or Iced Mocha, can 9.5 fl. oz. 90
Starbucks Frappuccino Coffee, bottle 9.5 fl. oz. 90
International Delight Iced Coffee 8 fl. oz. 76
Maxwell House Lite Ground Coffee 2 Tbs., makes 12 fl. oz. 50-70
Dunkin’ Donuts, Panera, or Starbucks Decaf Coffee 16 fl. oz. 15-25
Maxwell House Decaf Ground Coffee 2 Tbs., makes 12 fl. oz. 2-10


Serving Size

Caffeine (mg)

Starbucks Tazo Awake—Brewed Tea or Tea Latte grande, 16 fl. oz. 135
Starbucks Tazo Earl Grey—Brewed Tea or Tea Latte grande, 16 fl. oz. 115
Starbucks Tazo Chai Tea Latte grande, 16 fl. oz. 95
Starbucks Tazo Green Tea Latte—Iced or regular grande, 16 fl. oz. 80
Black tea, brewed for 3 minutes 8 fl. oz. 30-80
Snapple Lemon Tea 16 fl. oz. 62
Lipton Pure Leaf Iced Tea 18.5 fl. oz. 60
Green tea, brewed for 3 minutes 8 fl. oz. 35-60
Lipton 100% Natural Lemon Iced Tea, bottle 20 fl. oz. 35
Arizona Iced Tea, black, all varieties 16 fl. oz. 30
Nestea Unsweetened Iced Tea Mix 2 tsp., makes 8 fl. oz. 20-30
Arizona Iced Tea, green, all varieties 16 fl. oz. 15
Lipton Decaffeinated Tea—black or green, brewed 8 fl. oz. 5
Herbal Tea, brewed 8 fl. oz. 0

Soft Drinks

Serving Size

Caffeine (mg)

FDA official limit for cola and pepper soft drinks 12 oz. 71 (200 parts per million)
Pepsi MAX 12 oz. 69
Mountain Zevia (Zevia) 12 oz. 55
Mountain Dew, regular or diet 12 oz. 54 (20 oz. = 90)
Diet Coke 12 oz. 47 (20 oz. = 78)
Dr Pepper or Sunkist, regular or diet 12 oz. 41 (20 oz. = 68)
Pepsi 12 oz. 38 (20 oz. = 63)
Coca-Cola, Coke Zero, or Diet Pepsi 12 oz. 35 (20 oz. = 58)
Surge 8 oz. 35 mg (20 oz. = 87.5 mg)
Coca-Cola Life 12 oz. 27 mg (20 oz. = 45 mg )
Pepsi True 7.5 oz. 24 mg (20 oz. = 64 mg)
Barq’s Root Beer, regular 12 oz. 23 (20 oz. = 38)
7-Up, Fanta, Fresca, ginger ale, or Sprite 12 oz. 0
Root beer, most brands, or Barq’s Diet Root Beer 12 oz. 0

Energy Drinks

Serving Size

Caffeine (mg)

Bang Energy Drink 16 fl. oz. 357
Redline Energy Drink 8 fl. oz. 316
Rockstar Citrus Punched 16 fl. oz. 240
5-hour Energy 1.9 fl. oz. 208
Full Throttle 16 fl. oz. 200
Frava Caffeinated Juice 16 oz. 200 mg
Monster Energy 16 fl. oz. 160
Rockstar 16 fl. oz. 160
Venom Energy Drink (Dr Pepper/Seven Up Inc.) 16 fl. oz. 160
NOS Energy Drink (Coca-Cola) 16 fl. oz. 160
AMP Energy Boost Original (PepsiCo) 16 fl. oz. 142
NoDoz Energy Shots 1.89 fl. oz. 115
Mountain Dew Kick Start 16 fl. oz. 92
ávitāe Caffeinated Water 16.9 oz. 90 mg
Red Bull 8.4 fl. oz. 80
V8 V-Fusion+Energy 8 fl. oz. 80
Ocean Spray Cran-Energy 20 fl. oz. 55
Glacéau Vitaminwater Energy 20 fl. oz. 50
Starbucks Refreshers 12 fl. oz. 50

Caffeinated Snack Foods

Serving Size

Caffeine (mg)

Crackheads² 1 box, 40g 600
Crackheads Espresso Bean Candies, regular 1 package, 28 pieces 200
Wired Waffles 1 waffle 200
MiO Energy, all flavors 1 squirt, ½ tsp. 60
Crystal Light Energy ½ packet 60
Jelly Belly Extreme Sport Beans 1 package, 1 oz. 50
Jolt Gum 1 piece 45
Muscle Milk Orange Energy Chews 1.27 oz. 30 mg
Blue Diamond Almonds, Roasted Coffee Flavored 1 oz. 25
Perky Jerky 1 package, 1 oz. 10

Ice Cream & Yogurt

Serving Size

Caffeine (mg)

Bang!! Caffeinated Ice Cream 4 fl. oz. 125
Cold Stone Creamery Mocha Ice Cream Gotta Have It, 12 fl. oz. 52
Starbucks Coffee Ice Cream 4 fl. oz. 45
TCBY Coffee Frozen Yogurt large, 13.4 fl. oz. 42
Dannon All Natural Coffee Lowfat Yogurt 6 oz. 30
Häagen-Dazs Coffee Ice Cream 4 fl. oz. 29
Stonyfield Gotta Have Java Nonfat Frozen Yogurt 4 fl. oz. 28
Starbucks Mocha Frappuccino Ice Cream 4 fl. oz. 25
Baskin Robbins Jamoca Ice Cream 4 fl. oz. 20
Dreyer’s or Edy’s Grand Ice Cream—Coffee or Espresso Chip 4 fl. oz. 17
Breyers Coffee Ice Cream 4 fl. oz. 1
Häagen-Dazs Coffee Almond Crunch Snack Size Bar 1.8 oz. 10
Dreyer’s, Edy’s, or Häagen-Dazs Chocolate Ice Cream 4 fl. oz. less than 1

Chocolate Candy & Chocolate Drinks

Serving Size

Caffeine (mg)

Awake Caffeinated Chocolate Bar 1.55 oz. 101
Awake Caffeinated Chocolate Bites 0.53 oz. 50
Starbucks Hot Chocolate grande, 16 fl. oz. 25
Hershey’s Special Dark Chocolate Bar 1.5 oz. 20
Hershey’s—Milk Chocolate Bar 1.6 oz. 9
Hershey’s Kisses 9 pieces, 1.4 oz. 9
Hershey’s Cocoa 1 Tbs. 8
Dove Dark Chocolate Silky Smooth Promises 5 pieces, 1.4 oz. 4
Silk Chocolate Soymilk 8 fl. oz. 4
Hershey’s Chocolate Lowfat Milk, bottle 12 fl. oz. 2

Over-The-Counter Pills

Serving Size

Caffeine (mg)

Zantrex-3 weight-loss supplement 2 capsules 300
NoDoz or Vivarin 1 caplet 200
Excedrin Migraine 2 tablets 130
Midol Complete 2 caplets 120
Bayer Back & Body 2 caplets 65
Anacin 2 tablets 64

Pure Caffeine

Serving Size

Caffeine (mg)

Caffeine Powder 1/16 tsp. (200mg) 200 mg
Liquid Caffeine ½ tsp. (.08 oz.) 41.5

November 2014. Most information was obtained from company Web sites or direct inquiries.

Serving sizes are based on commonly eaten portions, pharmaceutical instructions, or the amount of the leading-selling contaner size. For example, beverages sold in 16-ounce or 20-ounce bottles were counted as one serving.

Additional information: Juliano, L.M. & Griffiths, R.R. (2005). “Caffeine.” In Lowinson, J.H., Ruiz, P., Millman, R.B., Langrod, J.G. (Eds.). Substance Abuse: A Comprehensive Textbook, Fourth Edition. (pp 403-421). Baltimore: Lippincott, Williams, & Wilkins.