How Much Caffeine is Too Much Caffeine?

Where is caffeine found?

Caffeine has been identified in more than 60 plant species and history suggests that it may have been consumed as far back as the Paleolithic period (1)! 

Currently, the most common dietary source of caffeine is coffee, but cocoa beverages, soft drinks, energy drinks, and specialized sports foods and supplements also contribute to regular intake (2). 

Caffeine is also present in many prescription and nonprescription (i.e., over-the-counter) medications, including some taken for headache, pain relief, cold, appetite control, staying awake, asthma, and fluid retention (3). 

Click here to learn how to turn your morning coffee or tea into a brain-boosting beverage!

What effects does caffeine have on the body?

After ingestion, caffeine is quickly absorbed from the gastrointestinal tract into the circulatory system and, once caffeine is absorbed, it promptly gets into all the body tissues and crosses the blood-brain, blood-placenta, and blood-testis barriers. Caffeine peaks in the blood anywhere from 15 minutes to 2 hours (4).

Caffeine is considered a drug because of its stimulant effects on the central nervous system. It has been found to positively influence cognitive performance, increase energy, and improve mood (5).


In epidemiological reports, a link between chronic caffeine consumption and a significantly lower risk of developing neurodegenerative diseases, such as Alzheimer’s disease, has been described. Caffeine has also been found to have a role in the prevention of physical degeneration due to Parkinson’s disease (6)

Other benefits of caffeine include improved mental alertness, speed reasoning, and memory, weight loss, improved physical performance during endurance exercise, and protection against certain skin cancers (7).

Negative side effects associated with caffeine is nervousness, anxiety, sleeplessness, irritability, dehydration, stomach upset, diarrhea, and nausea, increased heart rate, and both psychological and physical dependence (8).

What are the tolerable limits?

In adult men and non-pregnant women, the U.S. Food and Drug Administration considers 400 milligrams (about 4 cups brewed coffee) a safe amount of caffeine for healthy adults to consume daily. 

Pregnant women should limit their caffeine intake to 200 mg a day (about 2 cups brewed coffee), according to the American College of Obstetricians and Gynecologists.

The American Academy of Pediatrics suggests that children under age 12 should not consume any food or beverages with caffeine. For adolescents 12 and older, caffeine intake should be limited to no more than 100 mg daily. It may be worth noting, however, that many cultures around the world do introduce herbal tea that may contain caffeine to children as young as two years old.

for comparison

- 8oz of coffee contains 100mg of caffeine

- 8oz green tea contains 35 mg of caffeine

- a can of soda contains anywhere from 40-72 mg of caffeine

- energy drinks can range from 20-400mg+ of caffeine (yes, per drink!)

- and caffeine content of drugs varies from 16 mg to 200 mg per tablet

How to decide if caffeine is right for you

People have different tolerances and responses to caffeine, partly due to genetic differences. Take inventory of how you feel when you drink a caffeinated product, and decide for yourself what makes sense.

If you feel jittery, anxious, or addicted to the rush, then perhaps you should pull back on the caffeine and opt for a chemical-free Swiss Water® Process decaf coffee or natural uncaffeinated tea! If you feel great, then follow your body’s cues. 

Keep in mind that not all caffeinated products are created equal! Opting for organic,  whole-food sources of caffeine, like coffee, tea, or cacao is going to provide other additional nutrients that will benefit your body. In general, it’s smart to avoid sodas, energy drinks, and other highly processed items with artificial sources of caffeine— as they are unnatural and can cause inflammation and other negative side effects. 

SOURCES

1. Barone, J. J., & Roberts, H. R. (1996). Caffeine consumption. Food and Chemical Toxicology, 34(1), 119–129. doi:10.1016/0278-6915(95)00093-3 

2, 3, 5, 6. Cappelletti, S., Daria, P., Sani, G., & Aromatario, M. (2015). Caffeine: Cognitive and Physical Performance Enhancer or Psychoactive Drug? Current Neuropharmacology, 13(1), 71–88. doi:10.2174/1570159x1366614121

4. “Caffeine.” The Nutrition Source, 12 Nov. 2020, https://www.hsph.harvard.edu/nutritionsource/caffeine/.

7,8. “Caffeine: Benefits, Risks, and Effects.” Medical News Today, MediLexicon International, https://www.medicalnewstoday.com/articles/285194#risks.