When Creatine And Caffeine Are Taken Together, Here's What Can Happen To Your Poop

Most people are generally aware that adding sugar to your coffee is bad for you. With that said, this hasn't stopped society in general from devising new and unconventional ways to add some spice to coffee, literally and figuratively. With the rising popularity of various fad diets and health influencers, the list of potential coffee additions and enhancers just keeps getting longer and longer. (Read this to learn if you should be adding butter to your morning coffee.)

For some people, adding a little extra something to their coffee is an efficient means to increase their performance. This explains why the creatine-coffee combo has become a popular option among physically active and health-conscious coffee lovers. Some add a scoop or spoonful of creatine to a freshly brewed cup. However, with regard to the purported benefits of taking caffeine and creatine together, the conclusions aren't as clear-cut as one might think, as different studies seem to show different results.

More importantly, you'll want to be within range of a toilet when you try this combination — because there's a chance that consuming creatine and caffeine together will affect your digestive system in less-than-pleasant ways.

Separately, both creatine and caffeine have been observed to affect bowel movement for some people. Almost a third of the participants in a 2008 study published in Research in Sports Medicine experienced diarrhea after taking two 5-gram doses of creatine, with the diarrhea risk increasing by 56% when the dosage was doubled. 

Caffeine, on the other hand, has been known to sometimes cause an upset stomach, per a 2022 study in the International Journal of Sport Nutrition and Exercise Metabolism. This may be due to the substance's peristaltic effect, causing food to move through the bowels, which in turn may mean more trips to the bathroom (via a 2020 study in Nutrients).

As explained in a 2017 article in the Journal of Strength and Conditioning Research, caffeine inhibits muscle relaxation, while creatine does the opposite. Moreover, caffeine is a known diuretic, while creatine may actually promote water retention (which explains why some creatine users experience slight weight gain). Thus, when the two substances are consumed together, these conflicting effects may serve as the potential catalyst for gastrointestinal distress, though more research is needed before anyone can say this for certain.

But what about the other merits of a creatine-caffeine concoction?

In a 2024 study published in Nutrients, resistance-trained athletes who consumed 5 grams of creatine nitrate and 400 milligrams of caffeine daily for a week exhibited better performance in cognition-related tasks, with no side effects. On the other hand, authors of a 2022 review in the International Journal of Sport Nutrition and Exercise Metabolism observed that when creatine and caffeine are consumed together, over time, the latter could actually have a negative impact on the performance-enhancing capabilities of the former. Per another 2022 review in the Journal of the International Society of Sports Nutrition, chronic consumption of high doses of caffeine could be detrimental to creatine's otherwise positive effects on energy production and muscle performance.

A word of warning before you try a caffeine-creatine combo: Non-steroidal anti-inflammatory drugs (NSAIDs) are known to have a possible effect on kidney function, so as much as possible, avoid taking them with caffeine, creatine, or both. Also, pay attention to potential side effects (especially if you have any existing medical conditions).

Ultimately, it's wise to consult a medical professional before you make creatine-infused coffee a part of your diet, as it may end up being in your best interests to just enjoy your creatine and coffee separately. (Don't fret, though; there are other ways to make your morning coffee healthier.)