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How Much Caffeine is Too Much Caffeine?

Mmm…there’s nothing like that morning cup of coffee or tea! I promise, I enjoyed my caffeine for years and I understand how difficult and emotional it can be to think about going without. Personally, I found out that any amount of caffeine, on a regular basis, causes me to struggle with anxiety, clenching my jaw, grinding my teeth and feelings of insecurity. Weird, right!? My mental health was tied up with my caffeine consumption and I knew I had to give it up. Why is that?? Let’s find out.

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). 

What effects does caffeine have on the body?

After ingestion, caffeine is quickly absorbed from the gastrointestinal tract into the bloodstream. Once it’s in the bloodstream, caffeine promptly gets absorbed into body tissues and crosses over multiple barriers in the body, including the blood-brain barrier (a roadblock between your bloodstream and your brain which is there to protect your brain from toxins), the blood-placenta barrier for pregnant ladies, and the blood-testis barrier for men. 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 nervous system. It has been found to positively influence mental performance, increase energy, and improve mood (5).

Caffeine has been found to have a role in the prevention of physical degeneration from Parkinson’s disease (6) and studies have also shown that chronic caffeine consumption has been linked to a significantly lower risk of developing neurodegenerative diseases (meaning diseases that affect the brain and nervous system), such as Alzheimer’s disease.

Other benefits of caffeine consumption 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 include 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 of 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 of 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 teas that may contain caffeine to children as young as two years old.

For comparison:

• 8oz of coffee contains 100mg of caffeine

• 8oz of 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 how much 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 something caffeinated, 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 naturally uncaffeinated herbal tea. If you’re ultimately feeling better with less, 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.

So, you see, the short story is that caffeine is a mind-altering drug and should be treated with respect. If you’re struggling with unwanted symptoms, caffeine usage needs to be scrutinized and addressed.

P.S. I have just a few spots left for my Heal Your Heart and Your Hormones Women’s Retreat which is on April 30, 2022! Let’s make 2022 a year that you take time out to take care of yourself! Click here to learn more.

P.P.S. Things are rapidly changing here at Ann Jambor Functional Nutrition! Book a discovery call here if you want to get on my roster before I need to start a waitlist on March 1st! Clients who sign up for a VIP package will get a free ticket to the 2022 Women’s Retreat.


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,

7-8. “Caffeine: Benefits, Risks, and Effects.” Medical News Today, MediLexicon International,

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