How to drink caffeine strategically with the 5 Levels of Fatigue

Originally published January 13, 2017. Updated Sept 10, 2019.

During grad school, while working 2 jobs and researching full-time, I developed a system called the “5 Levels of Fatigue”.
It started out as a set of rules to help me consume caffeine more systematically – as I biochemist, I knew if I always picked the most potent drinks, caffeine wasn’t going to work on those days when I needed it the most.

Below, I’ll walk you through my system and how to use it to drink caffeine more strategically, MAXIMIZING caffeine’s benefits while MINIMIZING its side-effects.

For info on using the 5 Levels of Fatigue against boredom, burnout, and mental overwhelm, you’ll want to check out this page:
Click HERE

What’s the best energy drink? Everyone has their own preferences based on taste, but the scientific truth is “the best energy drink” depends on your body and your situation. Think of it this way:

An energy drink is like your favorite song: what gets YOU pumped up may do nothing for ME. A song that gets you up and moving on a Monday morning is probably not your go-to song to celebrate a Friday night.

Everyone is different, and different situations call for different solutions (that’s a beverage pun right there – in chemistry, a solution is a liquid mixture).

This is a picture of a card I made for a PhD student leaving my lab in grad school. To help her remember me, I drew a self-portrait. Big hair. Music. Caffeine.

I developed the 5 Levels of Fatigue in college and in grad school. I was juggling full-time studies with two part-time jobs. In addition to studying the science behind energy drinks, I was drinking them - a lot.

As a biochemistry major, I knew caffeine would stop working for me if my body got too used to it on a regular basis. Caffeine blocks adenosine, which prevents adenosine from sending you “YOU ARE GETTING SLEE-PY” signals. But after awhile your body realizes caffeine is blocking adenosine and MAKES MORE, so it takes MORE caffeine to feel the same energy boost.

Using the 5 Levels of Fatigue makes it less likely you'll develop caffeine dependence - it means you won't need more and more caffeine to feel awake.

Here's How It Works:

  • Every energy drink has a different amount of caffeine, juice, and sugar.
  • Some energy drinks are carbonated, some are not.
  • Carbonation, juice, and sugar content will all make one energy drink FEEL more powerful than another drink with the same amount of caffeine.

FATIGUE LEVEL 1: Dehydrated & Drowsy

At this level, you’re feeling a little drowsy, but not exhausted or overwhelmed.

SOLUTION = Do something Different. Go for a walk. Switch tasks. Take a 5 min break. Drink WATER. DO NOT drink any caffeine at this level.

Caffeine Informer Bai Antioxidant Infusion caffeine content

FATIGUE LEVEL 2: Too Tired

At this level, “I’m too tired” becomes the excuse for action. You’re not exhausted and not just bored or drowsy. You’re just a little bit off, a little sluggish, a little lethargic. You’re “too tired”.

SOLUTION = A LITTLE sluggish means A LITTLE caffeine. Look for caffeinated beverages with no more than 100 mg caffeine.

  • NON-carbonated beverages will provide a gentler boost because carbonation irritates the stomach lining so caffeine gets absorbed more quickly.
  • TEA-based beverages will also provide a gentler boost because L-Theanine has a calming effect.

FATIGUE LEVEL 3: Stressed & Struggling

At this level, you’re starting to feel overwhelmed. You’re trying to wake up but you’re really struggling to stay focused and engaged. A walk and a cup of tea aren’t going to cut it here, but it’s still not worst-case scenario “energy emergency” quite yet.

SOLUTION = Several scientific studies and international organizations say you should have no more than 200 mg caffeine at a time. So that’s what we’re looking for here.

  • HYBRIDS are the best option here – energy drink/coffee hybrids, energy drink/wannabe Gatorade drinks, caffeinated juice blends
  • Pick carbonated over non-carbonated for an extra boost if needed
  • Pick sugar-free or drinks where the only sugar comes from juice – save the full-sugar versions for those “energy emergencies” at Fatigue Level 4

FATIGUE LEVEL 4: Energy Emergency

At this level, we’re going to ignore health guidelines and go over that 200 mg caffeine per serving recommendation. This is an energy emergency. This is one step short of being a walking zombie. We’re talking just-trying-to-survive, counting-the-hours-before-I-can-go-home crisis.

SOLUTION = Choose a carbonated energy drink with more than 200 mg caffeine per can. You can also pick an energy shot because shots have higher caffeine mg per oz than energy drinks. Energy drinks with sugar will give you an extra boost though you may crash after a few hours so ONLY pick drinks with more than 10 grams sugar if you absolutely need that much more help.

FATIGUE LEVEL 5: Zombie

At this level, no amount of caffeine can save you. This is your absolute breaking point. This is worst-case-scenario.

SOLUTION = Only sleep can save you now.


This is the 5 Levels of Fatigue.

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Notable Ingredients

  • green tea leaf extract
  • guarana seed extract
  • yerba mate leaf extract
  • stevia and isomaltulose

Interesting and Unusual Ingredients In This Energy Drink

Isomaltulose is a natural sweetener found in honey and sugar cane extract. It has the same two “members” that make table sugar: glucose + fructose = sucrose. However the glucose and fructose are arranged (i.e., holding hands) in a different way than they do in sucrose.  As a result of this arrangement, isomaltulose is only half as sweet as sucrose.

This energy drink contains JABUTICABA, which is basically a Brazilian grape. Jabuticaba fruit contains protein, calcium, iron, phosphorus, Vitamin C and some B vitamins.

Jabuticaba has polyphenol antioxidants like those in cranberries and grapes. These antioxidants have been shown to have anti-inflammatory and anti-cancer properties…in test tubes and lab rats. It’s difficult to prove these benefits outside of a controlled cell or rat cage because life is too complicated to prove a cause and effect of this magnitude.  In other words, it’s extremely difficult to control for things like diet, stress, sunlight, exercise, the number of hours sitting down, etc. to conclusively prove whether polyphenols prevent cancer.

When Juice Becomes A Tool

Jabuticaba isn’t very high on the ingredients list, meaning there might not be enough of it in this drink to be an effective dose for those antioxidant health benefits. The same can be said for the other juices in here too: apple, grape, acai, and acerola. All of these juices offer some variety of health benefits related to the benefit of antioxidants. But the dosage makes a difference. So does the order.

Apple and Grape juice are the most predominant, and they are very sweet, which tells me this drink is using those juices more for flavor and sweetness than for health benefits.

Regardless, this is a healthier alternative to the stereotypical energy drink. This energy drink has 80 mg caffeine (same as Red Bull) from 3 leaf extracts: 1.Green Tea, 2.Guarana, 3.Yerba Mate. With 80 mg caffeine, this drink fits Fatigue Level 2. [See 5 Levels of Fatigue to see how to use this system to avoid caffeine toxicity, dependency, and tolerance]

You can find more about the science behind energy drink ingredients here at GreenEyedGuidecom and within my book, “Are You a Monster or a Rock Star: A Guide to Energy Drinks- How They Work, Why They Work, How to Use Them Safely” on Amazon (and now on Audible!!!).

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