The Neurobiology of Your Caffeinated Brain

by Daniel Singer | Thursday, Sep 04, 2025

Introductory Statistics  

Caffeine is the most widely used psychostimulant in the world, with around 80% of the world consuming roughly 200mg of caffeine daily (Samoggia & Rezzaghi, 2021). Specifically, roughly 92% of college students self reported caffeine consumption in 2021 (Mahoney et al., 2021).


Mechanism of Action 

Researchers still do not fully understand caffeine’s mechanism of action (MOA). . However, studies have uncovered numerous processes  contributing to its behavioral effects, the most notable being the inhibition of phosphodiesterase enzymes and the antagonism of adenosine. Suppressing phosphodiesterase enzymes, or proteins that break down cell signaling molecules in the body, increases glycogen consumption, which could cause the signature stimulatory effects of caffeine. Meanwhile, by blocking receptors for an inhibitory compound such as adenosine, neurotransmitters such as GABA, glutamate, dopamine, norepinephrine, and serotonin are affected.  Caffeine also increases the intracellular concentrations of a secondary messenger known as cAMP, which has been shown to lead to an increase in catecholamines such as dopamine and norepinephrine (Institute of Medicine, 2001).

 

Risk-Benefit Profile

The question of whether caffeine is safe or not is very complex. Proposed risks of caffeine may include but are not limited to: 

  • Fatality at high doses (10 - 14g) 
  • Physical dependence and withdrawal when used chronically 
  • Increased blood pressure 
  • Possible anxiety 

However, there also may be benefits to caffeine. Here are some possible benefits compiled from Kokot & Kratz, 2021 and Institute of Medicine, 2001: 

  • A lower risk of Alzheimer's Disease and Dementia 
  • Reduced risk of Parkinson's Disease 
  • Pain relief 
  • Lower risk for depression 

Like every substance, caffeine has its benefits and risks, especially with regular use. Most notably for college students, the increased ability to concentrate and stay alert are strong motivators to ingest caffeine. The FDA recommends a maximum of 400mg per day of caffeine for healthy adults, or roughly: 

  • Two (2) Celsius or Alani Cans  
  • Four (4) Cups of Brewed Coffee 
  • One and a Half (1.5) Monster Cans - Four (4) Cans of Redbull 

Conclusion  

 Although there are risks to its consumption, caffeine is generally safe when used in moderation. The potential benefits of caffeine are an interesting topic that warrants future research. For optimal safety, adults should not exceed the daily recommended dosage of 400 milligrams, for risk of adverse side effects.  


References  

Institute of Medicine (US) Committee on Military Nutrition Research. (2001). Caffeine for the sustainment of mental task performance: Formulations for military operations (Chapter 2, Pharmacology of caffeine). National Academies Press. https://www.ncbi.nlm.nih.gov/books/NBK223808/ Institute of Medicine (US) Committee on Military Nutrition Research. (2001). Caffeine for the sustainment of mental task performance: Formulations for military operations (Chapter 4, Safety of Caffeine Usage). National Academies Press. https://www.ncbi.nlm.nih.gov/books/NBK223808/ Mahoney, C. R., Giles, G. E., Marriott, B. P., Judelson, D. A., Glickman, E. L., Geiselman, P. J., & Lieberman, H. R. (2019). Intake of caffeine from all sources and reasons for use by college students. Clinical nutrition (Edinburgh, Scotland), 38(2), 668–675. https://doi.org/10.1016/j.clnu.2018.04.004 Rodak, K., Kokot, I., & Kratz, E. M. (2021). Caffeine as a Factor Influencing the Functioning of the Human Body-Friend or Foe?. Nutrients, 13(9), 3088. https://doi.org/10.3390/nu13093088 Samoggia, A., & Rezzaghi, T. (2021). The Consumption of Caffeine-Containing Products to Enhance Sports Performance: An Application of an Extended Model of the Theory of Planned Behavior. Nutrients, 13(2), 344. https://doi.org/10.3390/nu13020344