Energy Drinks in the News – The effects of Alpha-GPC versus caffeine on mood, cognitive function, and performance

Here at, my goal is to share the science behind energy drinks and their ingredients. In a study published in the Journal of the International Society of Sports Nutrition, caffeine goes head to head against Alpha-GPC in a battle of jitters and performance metrics. Which do you think is going to win?

This article is Open Access (hurray!) but, because it’s a poster presentation, it’s only two-pages long (aww….). Still, let’s dissect the details, shall we?

Is A-GPC vs Caffeine a fair fight?

According to the authors of this study, “Alpha-glycerylphophorylcholine (Alpha-GPC) and caffeine supplementation have been shown to improve mental and physical performance.”

[GEG: shown by whom? how convincingly? in what creature?]

All by itself, Alpha-GPC increases the release of the neurotransmitter acetylcholine. Neurotransmitters are chemicals that affect the ways nerves function.

Book Excerpts

Neurotransmitter 101 – an excerpt from The Energy Drink Guide (written by GreenEyedGuide):

“Speaking of delivering things, a neurotransmitter is a substance that sends a signal to its neighboring cells, prompting a reaction. The neurotransmitter histamine triggers allergic reactions like a runny nose and watery eyes. Serotonin triggers a calming sensation while norepinephrine and epinephrine trigger the “Fight-or-Flight” response in stressful situations. These neurotransmitters and a few others are made from amino acids, all with the help of B6.”


Alpha-GPC supposedly facilitates learning and memory.
So does caffeine. But which one does it better?


What Happened in the Study?

In this study, twenty people got one of four treatments:

  1. Caffeine – 200 mg
  2. Alpha-GPC – 200 mg
  3. Alpha-GPC – 400 mg
  4. Placebo – ???…no helpful details of any kind…

This study was randomized and cross-over, meaning everyone got to try each of the treatments on a different day, in different orders. This study was also double-blind, placebo-controlled, which means neither the scientists nor the participants knew who got what.

When a Research Paper Lets You Down

There are two phrases that burst my bubble of nerdy excitement when I’m reading a scientific study involving caffeine: “…in laboratory rats” and “not statistically significant”.

When an ingredient has promising health benefits….in laboratory rats, it makes me feel like the results are next to meaningless. I get that testing rats can be a precursor to testing people but, in my opinion, there’s too much uncertainty to assume people would see the same benefits.

When results are not statistically significant, half of me wants to stop reading the article. If your numbers are not statistically significant, then it’s all theory and trending assumptions. Yes, sometimes the things that are not “significantly significant” are significant in their importance.

The (Surprising and Disappointing) Results

When the participants had Alpha-GPC, their Serial Subtractions Test scores were ~1 second faster than when they had the caffeine (6.19 + 2.21 s versus 7.32 + 5.67 s). If you’re playing Jeopardy, that could be significant (See what I did there).

When the participants had Alpha-GPC, their Vertical Peak Jump Power was higher than when they had caffeine (2,041.3 + 547.2 W versus 1,920.4 + 689.6 W). Even though these results were depicted in the sole graphic figure in this paper presentation, it’s unclear whether this difference is significant.

When the participants had caffeine, they were more jittery as measured by a Visual Analog Scale for six different moods. Not only was this difference significant, statistically, it’s significant because these people only got 200 mg caffeine. And they were college age people!

  • A healthy adult can have up to 400 mg caffeine per day
  • Most flavors of Monster Energy contain ~160 mg caffeine
  • Some flavors of Rockstar Energy contain ~240 mg caffeine
  • A Starbucks Grande (plain black) coffee contains 330 mg caffeine
  • And 200 mg caffeine led to statistically significant jitters in this study?

What We Don’t Know

  • Whether the participants consume caffeine on a daily basis
  • What dosages of Alpha-GPC have been shown effective (IN PEOPLE)
  • Whether Alpha-GPC does anything meaningful (or “significant”) in terms of memory, mood, or performance (IN PEOPLE)
  • How long people have to take Alpha-GPC before it starts to give them a significant advantage
  • What was in the placebo
  • How the results would have compared if for one round the participants got BOTH Alpha-GPC + Caffeine

What’s Next?

Are you or do you know a grad student studying caffeine? Are you a professor or teacher leading a discussion on energy drinks and their ingredients? Are you looking for a caffeine expert to present to your class or at an event? If so, I want to hear from you!

I’ve studied energy drinks and their ingredients for over 10 years. I am constantly surprised by how many healthy alternatives or “new wave” energy drinks look nothing like their forefathers. I am also surprised how some energy drink rumors just won’t die (e.g., no, taurine does not come from bull sperm). My goal is to guide you, with my green eyes.

Get your copy of 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”


Let’s connect!






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