Should You Drink Water with Gels? The Complete Guide

November 14, 2025 •

4 min read

Over 60% of endurance athletes report gastrointestinal issues, with improper gel consumption often a contributing factor. This guide answers the critical question: should you drink water with gels? Understanding the type of gel and proper hydration technique is essential for performance and avoiding stomach upset during your activity.

Quick Summary

The necessity of drinking water with gels depends on the type. Traditional, concentrated gels require water to aid digestion and prevent stomach distress, while isotonic gels are pre-mixed and can be taken without extra fluid, though overall hydration remains vital.

Key Points

Water is Required for Classic Gels: Traditional energy gels are concentrated and must be consumed with water (around 4-6 oz) to aid digestion and prevent stomach issues.
Isotonic Gels Don't Require Extra Water: Isotonic gels are pre-mixed with water and can be taken without additional fluid, though overall hydration is still essential.
Taking Gels Without Water Causes GI Distress: Without water, concentrated gels can cause stomach cramps, bloating, and diarrhea by pulling water from your bloodstream into your gut.
Avoid Mixing Gels and Sports Drinks: Consuming a concentrated gel with a concentrated sports drink can lead to an overload of simple sugars, resulting in severe stomach upset.
Practice Your Fueling Strategy: Always test your gel and hydration plan during training to ensure your body can tolerate it on race day.
Timing is Crucial: Start fueling early during long activities (over 60-90 minutes) and consume gels at regular intervals to avoid hitting the wall.

The Fundamental Role of Hydration with Gels

Energy gels are a concentrated source of carbohydrates designed to provide a rapid energy boost during sustained physical activity. For these concentrated sugars to be effectively absorbed and utilized by your body, they must be adequately diluted. During intense exercise, your body diverts blood flow away from the digestive system and towards your working muscles. This makes the digestive system more sensitive and less efficient at processing concentrated substances. Consuming a highly concentrated gel without water forces your body to pull existing water from your bloodstream and tissues into the digestive tract to dilute the sugars. This can lead to worsening dehydration, slowing the absorption of carbohydrates, and causing gastrointestinal (GI) distress.

Classic vs. Isotonic: The Critical Difference

Not all gels are created equal, and the type of gel you use dictates your hydration strategy. Differentiating between classic and isotonic gels is the most important step in preventing on-the-go stomach issues.

Classic Energy Gels

Composition: These are thicker, more concentrated gels containing a higher carbohydrate load and less water.
Hydration Rule: You must drink water with classic gels. A common recommendation is 4 to 6 ounces of plain water per gel to help with absorption and prevent stomach upset. Without water, these gels can be very difficult for your body to process, leading to the risk of cramps, bloating, and diarrhea.

Isotonic Energy Gels

Composition: These gels have a thinner consistency because they are pre-mixed with water and electrolytes to be at a similar concentration to your body's fluids.
Hydration Rule: You do not need to take additional water specifically to aid the gel's absorption. This offers convenience for runners who don't want to carry a water bottle. However, this does not mean you can neglect your overall hydration plan. You still need to drink water or other fluids regularly throughout your exercise to replenish what is lost through sweat.

Risks of Improper Gel Consumption

Skipping water with a non-isotonic gel can lead to a host of problems that can quickly derail your performance:

Gastrointestinal Distress: The most common issue, manifesting as bloating, cramping, nausea, or diarrhea. This is a direct result of the gut pulling water from other parts of the body to process the concentrated sugar.
Ineffective Fueling: The absorption of the gel is delayed, meaning the quick energy boost you're seeking is not delivered efficiently.
Worsening Dehydration: Your body's fluid balance is compromised as water is diverted from the bloodstream, hindering performance and increasing the risk of heat-related illness.
Energy Crash: A flood of simple sugars without proper absorption can lead to a rapid spike and subsequent crash in blood sugar levels.

How to Create a Smart Fueling Strategy

To maximize the benefits of energy gels while minimizing risks, follow these best practices:

Practice in Training: Never try a new gel or fueling strategy on race day. Use your training runs to test different brands, gel types, and your hydration plan to see what your stomach tolerates best.
Time Your Intake: For activities over 60-90 minutes, start fueling early. Take your first gel around 45-60 minutes into the exercise, and then every 30-45 minutes thereafter.
Use Water, Not Sports Drinks: When consuming a classic gel, pair it with plain water. Do not wash a gel down with a sports drink, as the combined high sugar concentration can overload your digestive system.
Sip, Don't Chug: Take small, consistent sips of water with your gels rather than large gulps. This helps maintain fluid balance and supports digestion.

Comparison: Classic vs. Isotonic Gels


Feature	Classic Energy Gel	Isotonic Energy Gel
Water Required?	Yes, with every gel packet.	No, pre-mixed with water.
Carbohydrate Density	High	Lower
Consistency	Thicker, denser	Thinner, more fluid-like
Primary Purpose	Compact, quick energy source	Energy and hydration support
Convenience	Less convenient without water access	More convenient for runners without water
Risk of GI Distress	High, if taken without water	Low
Best Use Case	Endurance athletes with a solid hydration plan	Runners who want to avoid carrying extra fluid for gel consumption

Conclusion: The Bottom Line on Gels and Water

Ultimately, the question of whether you should drink water with gels depends on the type of gel. For traditional, non-isotonic gels, the answer is a definitive yes—it is essential for digestion, absorption, and preventing stomach issues. For isotonic gels, while it is not strictly necessary for absorption, you must still maintain adequate hydration throughout your workout with either water or an electrolyte drink. The key to successful fueling is to train your gut, understand your gel type, and consistently pair traditional gels with water during your endurance activities. Neglecting this crucial hydration step can lead to a frustrating end to your race or long training session. For more expert advice on endurance nutrition, visit Runner's World.

Frequently Asked Questions

If you take a traditional, non-isotonic energy gel without water, its concentrated sugars can cause gastrointestinal distress, including bloating, cramping, and diarrhea. Your body will pull water from other areas into your digestive tract to dilute the gel, which can worsen dehydration and slow absorption.

For a classic energy gel, it is recommended to drink approximately 4 to 6 ounces (two to four sips) of plain water with it to aid digestion and absorption. This helps to properly dilute the concentrated carbohydrates.

Yes, isotonic gels are specifically formulated with water, so they can be absorbed efficiently without additional water. However, they do not replace your overall hydration needs, and you should continue to drink water throughout your exercise.

No, it is best to avoid combining traditional energy gels with sports drinks. Both are sources of concentrated carbohydrates, and combining them can lead to an overload of sugar that can upset your stomach.

For endurance activities, you should typically consume a gel every 45 to 60 minutes, beginning about 60-90 minutes into your workout. Always practice your timing during training to find what works best for you.

The key difference is the water content. Classic gels are highly concentrated and require you to drink water with them for proper digestion, while isotonic gels are pre-diluted with water and do not require extra fluid to be consumed alongside them.

The most common side effects are gastrointestinal issues like stomach cramps, bloating, and nausea, often caused by improper consumption, especially taking concentrated gels without enough water. Experimenting with different brands and practicing during training can help mitigate these issues.

For most runs under an hour, energy gels are not necessary as your body has sufficient glycogen stores. They are most beneficial for activities lasting longer than an hour.