Caffeine is the stimulatory drug of choice for many bodybuilders and gym goers alike. Unbeknownst to laypeople who regularly drink coffee, caffeine is largely responsible for the feelings of ‘energy’ and motivation that arise afterwards.

Over the past decade, a multitude of energy drinks and sports beverages have cropped up in grocery stores and gas stations all over the world. These drinks are loaded with exorbitant doses of caffeine though, making them addictive and harsher on the body than most people realize.  Moreover, practically every pre-workout supplement you find these days is packed with caffeine and little else that’s worthwhile for performance-enhancement.

It’s unfortunate that many people are uninformed about caffeine and its role in the human body; thankfully, this guide is going to remedy that by informing readers about what caffeine is, its role in the body, the pros and cons of it, and how to dose it properly. If you use caffeine wisely/in a structured fashion, it can be a highly beneficial adjunct to your supplement regimen and help you achieve your performance and physique goals.

Chemical Nature of Caffeine

Chemically speaking, caffeine (also sometimes referred to as 1,3,7-trimethylxanthine) is a basic (high pH), organic substance related to compounds called methylxanthines . These compounds are naturally present in cocoa, coffee, green/black tea, and various other plants.

Biochemically, caffeine acts as acetylcholinesterase (ACE) and phosphodiesterase (PDE) enzyme inhibitors; inhibition of PDE enzymes are purported to give caffeine many of its performance-enhancing properties in humans. PDE enzymes are necessary for metabolism of two critical cellular messengers - cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP).

Thus, inhibition of PDE enzymes (such as when caffeine is ingested) causes cAMP and cGMP activity to rise. In turn, cellular metabolism increases, causing you to feel ‘wired’ and stimulated.

Physiology of CNS Stimulation

The CNS pertains to brain and spinal cord - the most crucial system in humans for transmitting signals from one body part to another. When CNS stimulants like caffeine are ingested, breakdown of cGMP and cAMP decreases, sending the body into a mode of excitation. The immediate ramifications are:

  • Elevated heart rate
  • Cognitive stimulation (i.e. feeling “wired”)
  • Constriction of blood vessels
  • Bronchodilation
  • Minor increase in metabolic rate
  • More frequent urination/excretion


Furthermore, caffeine stays in the system for upwards of 6 or more hours, so taking it at certain times (particularly towards bedtime) is imprudent. Some of the aforementioned effects may be quite desirable for bodybuilders and gym goers; however, inhibition of blood flow and increased urinary frequency can interfere with training.  This is why MPA Celluvol is a stimulant-free pre-workout made with ingredients proven to increase cell volume and blood flow.

On the same token, bodybuilders and other physique competitors can benefit from properly timed caffeine use before contest as it acts as a diuretic. Vasodry Professional is a topical gel formulated with key methylxanthines, such as caffeine and theobromine, which give your skin a tighter, firmer texture.

Caffeine’s Effects on Athletic Performance

Research suggests that caffeine benefits athletes primarily by expanding bronchial tubes, promoting more efficient respiration; caffeine also significantly increases catecholamine (e.g. dopamine, adrenaline, etc.) levels, which has a variety of benefits on physical performance. (1, 2) A variety of literature demonstrates that athletes feel increased sense of focus and energy after taking caffeine, which decreases rate of perceived exertion. (3, 4)

In turn, caffeine’s ergogenic effects, both psychologically and physiologically, increase your capacity to perform work (especially when lifting weights and doing cardio). Caffeine also appears to increase the thermic effect of feeding (TEF) and promote carbohydrate and fatty acid utilization while exercising. (5, 6)

Pros & Cons of Caffeine Use (Pre-Workout)

Nearly every pre-workout product on the market has caffeine in it for a reason--because it gets people ‘amped’ up. However, users need to be wary of their caffeine use because it can be detrimental when overconsumed. On the same token, proper caffeine use may be beneficial for certain demographics.

Competitive bodybuilders and gym goers can benefit from intermittent caffeine use, particularly before a cardio or training session. As mentioned earlier, though, caffeine constricts blood vessels and may not be ideal taken prior to resistance training.  Also, most athletes involved in sports that require accurate coordination, such as basketball and baseball, will likely find that caffeine hampers performance.

In short, the performance-enhancing effects of caffeine arise from:

  • Elevations in catecholamine production
  • Bronchodilation
  • More efficient glucose metabolism
  • Increases in fatty acid utilization


Caffeine use is not without a variety of unwanted side effects, including:

  • Dehydration/muscle cramps (remedied by proper fluid intake)
  • Frequent urination
  • Heart palpitations
  • Decrease in precision motor skills/coordination
  • Gastrointestinal distress/Stomach upset
  • Jitteriness
  • Increased cortisol levels(7)


To avoid these ramifications, some trial and error will be needed. Depending on how sensitive your body is to caffeine, you may only need a small dose (e.g. 1mg per kilogram of bodyweight). Bigger individuals may require upwards of 3mg of caffeine per kilogram of bodyweight to notice much at all. [9]

Begin with a minimal dose for your bodyweight and assess how you responds. For most people, one 8oz cup of coffee (which contains roughly 100mg of caffeine) is a good starting point.

Take-home Points

Now that have a better understanding of this ubiquitous stimulant, hopefully you can reap its benefits and avoid any unwanted side effects. Remember that caffeine is a drug, and needs to be treated like any other addictive substance. Using it too often will result in performance decrements both physically and psychologically. However, when used in the right fashion, it can indeed be useful for most any gym goer.


  1. Battram, D. S., Graham, T. E., Richter, E. A., & Dela, F. (2005). The effect of caffeine on glucose kinetics in humans – influence of adrenaline. The Journal of Physiology, 569(Pt 1), 347–355.
  2. Becker AB, Simons KJ, Gillespie CA, Simons FE. The bronchodilator effects and pharmacokinetics of caffeine in asthma. N Engl J Med. 1984 Mar 22;310(12):743-6.
  3. Doherty, M., & Smith, P. M. (2005). Effects of caffeine ingestion on rating of perceived exertion during and after exercise: a meta‐analysis. Scandinavian journal of medicine & science in sports, 15 (2), 69-78.
  4. Woolf K, Bidwell WK, Carlson AG. The effect of caffeine as an ergogenic aid in anaerobic exercise. Int J Sport Nutr Exerc Metab. 2008 Aug;18(4):412-29.
  5. Acheson, K. J., Zahorska-Markiewicz, B., Pittet, P. H., Anantharaman, K., & Jequier, E. (1980). Caffeine and coffee: their influence on metabolic rate and substrate utilization in normal weight and obese individuals. The American journal of clinical nutrition, 33(5), 989-997.
  6. Graham, T. E., Battram, D. S., Dela, F., El-Sohemy, A., & Thong, F. S. (2008). Does caffeine alter muscle carbohydrate and fat metabolism during exercise?.Applied Physiology, Nutrition, and Metabolism, 33(6), 1311-1318.
  7. Beaven CM, Hopkins WG, Hansen KT, Wood MR, Cronin JB, Lowe TE. Dose effect of caffeine on testosterone and cortisol responses to resistance exercise. Int J Sport Nutr Exerc Metab. 2008 Apr;18(2):131-41.
  8. Glaister M, Patterson SD, Foley P, Pedlar CR, Pattison JR, McInnes G. Caffeine and sprinting performance: dose responses and efficacy. J Strength Cond Res. 2012 Apr;26(4):1001-5. PubMed PMID: 22388491.
  9. Del Coso J, Salinero JJ, González-Millán C, Abián-Vicén J, Pérez-González B. Dose response effects of a caffeine-containing energy drink on muscle performance: a repeated measures design. J Int Soc Sports Nutr. 2012 May 8;9(1):21. PubMed PMID: 22569090.