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.

The Science Behind Turbo Tea Zero from A.B.B.

Energy drinks are a spectrum. While there are some that look exactly like the stereotypical energy drinks from the early 2000s, there are a growing number which look nothing like their forefathers. Every month I try to highlight an energy drink which doesn’t fit the stereotype. This month, we’ll review the science behind a drink which could be considered an energy drink, a pre-workout, maybe even a tea. Read more

Ashwagandha and antioxidants in an Energy Drink? Science Behind Crunk!!! – Energy Drink of the Month

In January we face the difficult task of setting goals for the year. We aim high. Sometimes we fall short. But as Brene Brown taught us, sometimes we have to look at the attempt itself as the victory. It’s far easier not to try and play it safe. Thus, in the spirit of Daring Boldly, let’s talk about the energy drink that strives to break the mold. If you avoid energy drinks because you’re afraid of health risks, consider the science behind Crunk!!! Energy. Read more

Science Behind Xyience Energy Drink

The world of energy drinks is vast, and there isn’t enough time to give every drink the full “Energy Drink of the Month” deep dive review. In my attempt to guide my fans through this world of energy drinks, I like to share the science behind the various caffeinated beverages I come across in my travels.

On a request from one of my fans via Instagram, here is the Science Behind Xyience!

Photo Editor-20171129_141330

Caffeine

Caffeine comes from plain caffeine and from guarana seed extract. There’s 176 mg caffeine per can (88 mg per serving and 2 servings per container). According to Caffeine Informer, Xyience used to be 200 mg per can. Either way, it’s Fatigue Level 3.

Key Ingredients

This drink contains B-vitamins, and some stereotypical energy drink ingredients including guarana, glucuronolactone, taurine, ginseng root extract, and inositol.

  • Glucuronolactone might feed one reaction that helps the body generate energy, but glucuronolactone has to go through some small transformations first, and this reaction (the Pentose Phosphate Pathway) isn’t a major reaction, energy wise
  • Taurine is a taxi cab that helps shuttle water-hating fat molecules to the place they need to be metabolized
  • Ginseng is supposed to help with stress but a systematic review of almost 500 studies involving Panax Ginseng found the only benefit was for glucose metabolism in animal models
  • Inositol helps with insomnia…(kind of ironic, right?)
  • B-Vitamins include 100% of niacin (my favorite vitamin), 250% of B6, 80% of B12, and 500% (why?) of Pantothenic Acid
    • Niacin is part of over 200 reactions in the body, most of them involving the production of ENERGY.
    • B6 helps our bodies make those non-essential amino acids and also helps us maintain optimal blood sugar levels.
    • B12 helps our bodies make healthy red blood cells
    • B5 helps with the metabolism of carbs, fat, and protein, but there’s so much of it in every food group no one needs a B5 supplement (in my opinion)

Other Notes

Preservatives in this drink include potassium sorbate, potassium benzoate, and sodium citrate.

  • Potassium sorbate – this anti-microbial preservative prevents yeast and mold growth in sodas and other foods. The Center for Science in the Public Interest (CSPI) rates this as safe. If the CSPI, who has a reputation for fear-mongering and chemophobia, rates this safe, you should definitely feel at ease. [See Panera KNOW-No Project Part IV]
  • Sodium Benzoate – Did you know that benzoate salts like this one prevent the growth of microorganisms like yeast and mold? Benzoate salts are often used with other preservatives especially at low pH (acidic food). People can ingest up to 5mg per kg of body weight of benzoic acid and its salts according to European Commission – Scientific Committee on Food. 
  • Sodium Citrate and Citric Acid – both are abundant naturally in citrus fruits and are used in beverages to help control the pH.

Fruit and vegetable juice is used for color, but this drink has artificial sweeteners Ace-K and Sucralose. But there are only 2 grams of carbs (from the juice, most likely) and zero Calories, zero grams of sugar.

What drink should I review next?

You can find more about the science behind energy drink ingredients here at GreenEyedGuide.com 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!!!).

Let’s connect!

Science Behind Dark Dog Organic energy drink – Quick Review

The world of energy drinks is vast, and there isn’t enough time to give every drink the full “Energy Drink of the Month” deep dive review. In my attempt to guide my fans through this world of energy drinks, I like to share the science behind the various caffeinated beverages I come across in my travels.

Science Behind Dark Dog Organic energy drink

Read more