Why Does Coffee Make My Stomach Hurt But Not Energy Drinks?

December 28, 2025 •

4 min read

According to a study cited by the National Institutes of Health, some bitter compounds found in coffee can stimulate gastric acid production, leading to common digestive complaints. This phenomenon often confuses people who can consume energy drinks without any similar stomach upset.

Quick Summary

Coffee's acidity and specific organic compounds stimulate gastric acid production, irritating the stomach lining, while energy drinks often contain buffers and other ingredients that mitigate this effect. Individual sensitivity to these compounds and caffeine levels also plays a significant role in digestive distress.

Key Points

Coffee's Acidity Triggers Gastric Acid: Specific compounds in coffee, not just its pH level, can stimulate the stomach to produce more acid, leading to irritation.
Energy Drinks Contain Mitigating Ingredients: Many energy drinks are formulated with ingredients like B-vitamins and taurine, which can support gut health and do not trigger the same gastric acid response as coffee.
Individual Sensitivity is Key: Digestive issues are often personal; some people are simply more sensitive to coffee's compounds, caffeine, or tannins.
Cold Brew is a Gentler Alternative: The cold brewing process extracts fewer of the acidic compounds from coffee beans, making it a much smoother option for sensitive stomachs.
The Empty Stomach Factor: Drinking coffee without food provides no buffer for the stomach lining, increasing the likelihood of irritation from gastric acid.
Additives Can Contribute to Discomfort: It's not always the coffee itself; ingredients like milk, cream, or sugar can cause problems for those with lactose or fructose intolerances.
Caffeine Plays a Role in Motility: Caffeine in both beverages can speed up digestive tract contractions, which can be perceived as an upset stomach or lead to an urgent bowel movement.

Understanding Coffee's Unique Digestive Impact

For many, a morning cup of coffee is an essential ritual. For others, it's a guaranteed path to stomach pain, heartburn, or indigestion. The key to understanding this lies in coffee's complex composition, which goes far beyond just caffeine. While both coffee and energy drinks contain caffeine, coffee includes a host of other natural acids and compounds that contribute to its distinctive digestive effect.

The Role of Coffee's Acidity and Compounds

Contrary to a common misconception, coffee itself isn't exceptionally acidic when compared to stomach acid, but its components trigger the stomach to produce more of its own acid. Chlorogenic acids, N-alkanoyl-5-hydroxytryptamides, and other compounds found in coffee have been shown to stimulate gastric acid secretion. This increase in gastric acid can irritate the stomach lining, especially if consumed on an empty stomach, and may worsen conditions like GERD or gastritis.

Furthermore, coffee contains tannins, which are bitter, astringent compounds that can irritate the gut lining for sensitive individuals. The specific compounds and their concentrations vary depending on the coffee bean type, roast level, and brewing method. Darker roasts, for example, tend to have lower levels of certain irritants, while cold brewing extracts fewer of these compounds compared to hot brewing.

How Energy Drinks Are Different

Energy drinks, while often more acidic overall than coffee, are formulated to bypass these specific digestive issues. They typically use a different form of caffeine, often synthesized, and are loaded with sugars and artificial ingredients that can have their own health drawbacks, but which do not trigger the same gastric acid response.

Here's a list of ingredients and their functions in energy drinks:

Taurine: An amino acid that may have antioxidant properties and support overall gut health, helping protect the digestive system.
B-Vitamins: These vitamins aid in energy metabolism and can support a healthy gut microbiome, contributing to better digestion.
Sweeteners and Sugars: High sugar content can feed pathogenic bacteria in the gut, but also acts as a quick, soluble carb source that doesn't trigger the same gastric acid spikes as coffee's compounds.
Carbonation and Artificial Flavors: While potentially unhealthy in excess, these ingredients do not contain the specific acidic compounds (like chlorogenic acids) found in natural coffee beans that stimulate excess gastric acid secretion.

Comparison: Coffee vs. Energy Drinks for Digestive Health


Feature	Coffee	Energy Drinks
Key Stimulant	Naturally occurring caffeine from coffee beans.	Often synthetic caffeine with other stimulants.
Acidity Mechanism	Compounds like chlorogenic acids directly trigger increased gastric acid secretion.	High overall acidity is often buffered by other ingredients.
Stomach Lining Impact	Can irritate the stomach lining, especially on an empty stomach, due to specific acidic triggers.	High sugar content can negatively affect gut bacteria over time but less likely to cause immediate, sharp pain.
Tannins Presence	Contains tannins, which can increase bitterness and irritate some sensitive stomachs.	Do not contain tannins, avoiding this specific source of irritation.
Digestive Motility	Strong stimulant effect on gut motility, potentially leading to loose stools or an urgent need to use the bathroom.	Also stimulates gut motility, but the overall effect on the digestive tract can differ based on formulation.
Additives	Additives like milk or sugar can cause issues for those with lactose intolerance or fructose sensitivity.	Contain a wide array of artificial ingredients and sweeteners, which may cause different types of gastric issues for some.

Mitigation Strategies for Coffee Drinkers

For those who experience stomach pain from coffee, there are several methods to lessen its impact without switching completely to energy drinks. Choosing a high-quality, low-acid coffee can make a significant difference. Certain brewing methods can also reduce the levels of irritants. For instance, cold brewing involves a longer steeping time in cold water, which extracts fewer of the acidic compounds that cause digestive problems.

Additionally, timing your coffee consumption can help. Drinking coffee with a meal, rather than on an empty stomach, can provide a buffer that protects the stomach lining. If caffeine sensitivity is the primary issue, switching to decaf or slowly reducing your intake can also be effective. Finally, experimenting with additives—using non-dairy milk or less sugar—might be the simple fix some need.

Conclusion

The difference in how coffee and energy drinks affect your stomach boils down to their core ingredients. Coffee's natural acids and other compounds specifically trigger your stomach's acid production, causing irritation and pain for sensitive individuals. Energy drinks, while often high in sugar and synthetic caffeine, lack these specific compounds and are formulated differently, leading to a varied digestive experience. By understanding these distinctions, and implementing strategies like switching to cold brew or eating with your coffee, you can find a way to enjoy your daily boost without the discomfort.

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Frequently Asked Questions

Yes and no. While the chemical compound is the same, coffee's caffeine is naturally occurring and comes alongside other compounds like acids and tannins, while energy drinks often use synthetic caffeine in a different formula with other additives.

Yes, for many people. Consuming coffee on an empty stomach removes the food buffer that helps neutralize the acidic compounds, making irritation and stomach pain more likely.

Not necessarily. Many energy drinks have a lower pH and are more acidic overall than coffee. However, they are formulated differently and lack the specific compounds that trigger increased gastric acid secretion in the same way coffee does.

It might. Decaf coffee can reduce stomach discomfort if caffeine is the main trigger for your digestive issues. However, decaf coffee still contains the other acids and compounds that can stimulate gastric acid production, so it is not a complete solution for everyone.

Yes, many people find cold brew easier on their stomach. The cold water extraction process yields a less acidic and smoother brew by extracting fewer of the irritant compounds found in coffee beans.

Yes, absolutely. For individuals with lactose intolerance, dairy additives can be the primary cause of digestive issues like bloating and stomach cramps, rather than the coffee itself.

Opt for dark roast or cold brew options, which are generally less acidic. High-quality, low-acid beans can also be a good choice. You can also try drinking coffee alongside a meal to help buffer the effects.