Health and wellness influencers give a lot of advice. Sometimes, their advice may come from a place of good intentions, but it is not uncommon for wellness influencers to give advice that is not backed up by science. So, one of my favorite things to do is fact-check claims made by health influencers. And today we are going to be talking about caffeine. Is caffeine safe? Is caffeine healthy? How much caffeine can you consume? This is what we will discuss today!
*Disclaimer: As always, this is general information intended for healthy adults. Your needs may vary based on medical status, lifestyle, or life-stage. Please never replace generalized health information you’ve read online with individualized clinical care.
First of all, what is caffeine? What foods and beverages contain caffeine?

Caffeine is a bitter substance that occurs naturally in more than 60 substances including coffee beans, tea leaves, cocoa pods (made into coffee), and kola nuts (used to flavor soda).
Caffeine may also be added to various beverages, food products, and supplements, including ‘pre-workout.’ It is also found in some over the counter pain relievers.
Coffee is the primary source of caffeine in the American diet. Soft drinks, energy drinks, teas, supplements, and caffeinated food products are other sources.
A home brewed cup (8 ounces) of coffee contains about 40 mg caffeine. A cup of green tea has about 35 mg. A grande (16 ounce) cup of blonde roast coffee from Starbucks has 360mg. A grande (16 ounce) Nitro Brew from Starbucks has about 280mg caffeine.
Of note, ‘decaffeinated’ beverages are not always void of caffeine. Decaf coffees and teas do have less caffeine than their caffeinated counterparts, however, they may still contain low levels of caffeine. For example, a decaf coffee may have 2-15 mg of caffeine in an 8-ounce cup compared to a usual 40 mg, but it’s not caffeine-free.
What does caffeine do to the human body?
Caffeine has many effects on the human body. Of note, caffeine is considered a mild stimulant, as it stimulates the central nervous system. This can make you feel more awake, mentally alert, help you focus, and/or give you a boost of energy.
Caffeine is also a natural mild diuretic, meaning it helps the body remove extra salt, leading to increased urination.
How long do caffeine’s effects last?
It takes most people 3-6 hours to metabolize half of what has been consumed. Caffeine levels tend to peak 30-120 minutes post-consumption.
How much caffeine is safe?
Generally speaking, for most healthy people, consuming up to 400mg of caffeine per day is considered safe. Caffeine tolerance varies from person to person. Some people may be much tolerant of smaller amounts of caffeine than others.
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