Myth Busting Caffeine

From energy boosts to dehydration myths, here’s what caffeine really does to your body, according to science.

While caffeine is part of most people’s morning routines, there are a lot of misconceptions about what it can and can’t do for us.

What is caffeine?

Caffeine is a stimulant that can occur naturally in foods like cocoa and coffee or be added to products like energy drinks and caffeine mints. Most people consume caffeine through coffee, tea, and soda. While caffeine is mainly used as a way for people to energize themselves, there are certain medical uses for caffeine, such as treating apnea of prematurity or migraines.

How much caffeine is too much?

The FDA recommends that healthy adults keep their caffeine intake below 400mg of caffeine per day, as this amount is not generally associated with negative side effects. That said, sensitivity to caffeine varies significantly between individuals. There are specific populations who need to avoid caffeine, like young children, as well as medical circumstances where caffeine intake should be limited (for example, certain medications may interact with caffeine, or conditions like cardiac arrhythmias may require caffeine to be avoided or limited).

How much caffeine is in my morning beverage?

The caffeine content of coffee can vary greatly depending on how it is brewed, the type of coffee bean used, and even how coarsely it is ground. The following values are sourced here from the FDA or, where noted, are based on a specific brand such as Starbucks.

Beverage

Caffeine Content

1.5 oz Espresso (Starbucks)

150mg

12 oz caffeinated soda

23–83mg

12 oz drip coffee

113–247mg

12 oz black tea

71mg

12 oz green tea

37mg

12 oz energy drinks*

41–246mg

*It is important to read the label on energy drinks, as these vary greatly in the amount of caffeine they provide.

Myth-Busting Caffeine

Myth #1: You can’t have ANY caffeine if you are pregnant.

If you are pregnant, a little caffeine is okay. It is recommended that anyone who is pregnant limit their caffeine intake to less than 200mg per day. For those who are breastfeeding, the recommended intake is less than 300mg per day. What is important to keep in mind is that caffeine is not just found in your morning coffee; it also exists in tea, chocolate, and soda, which should factor into daily caffeine intake.

Myth #2: Decaf is caffeine-free.

Decaffeinated coffee and tea still contain a small amount of caffeine. While the amounts are negligible, these products are not considered caffeine-free. For instance, decaf coffee still contains about 2–15mg of caffeine per 8-ounce serving.

Myth #3: If you have a high tolerance, you can have as much caffeine as you want.

Even those with a high tolerance should keep their caffeine intake below 400mg per day. There are potential adverse effects from consuming excess caffeine that range from mild to severe. Having a bit too much caffeine can result in symptoms like irritability, increased anxiety, jitters, and insomnia, while more severe side effects include disorientation, seizures, and arrhythmias. Caffeine can be potentially lethal if you consume 5,000mg of caffeine or more; however, it is very unlikely that you would get anywhere close to this amount through coffee or energy drinks alone. Be sure to exercise caution and pay close attention to dosage with any caffeine pills or powders.

Myth #4: Caffeine dehydrates you.

Research suggests that caffeine may not actually cause dehydration. One meta-analysis found that caffeine intake of around 300mg in healthy adults had only a mild diuretic effect, which was ultimately negated by exercise. It concluded that if you are consuming caffeine in normal amounts, you do not need to worry about it causing unwanted fluid loss. Other studies similarly found that caffeine has little to no effect on fluid balance.

Myth #5: Caffeine can sober you up.

This is false; caffeine does not make alcohol move through your system any faster. Caffeine may make you feel more alert, but it does not change the level of impairment you experience from drinking alcohol. For the effects of alcohol to wear off, it must be broken down by the liver and excreted. Caffeine does not speed up or alter this process.

TL;DR

Caffeine can be safe for most people as long as it is consumed in moderation and within the recommended intake limits.

Words by Madeline Peck, RDN, CDN, Huel Nutrition Team