6 Best Energy Gels For Running That Won’t Upset Your Stomach

You’re 18 miles into a marathon, right on pace, when a familiar rumble starts deep in your gut. Suddenly, your stride, your breathing, and your mental focus are all secondary to a single, urgent thought: "Where is the nearest porta-potty?" A bad energy gel can derail months of training faster than a steep hill, turning a goal race into a survival shuffle. Finding fuel that works with your body, not against it, is one of the most critical and personal parts of endurance running.

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Why Most Gels Cause GI Distress in Runners

Ever wonder why that sticky, super-sweet gel you choked down an hour ago is now staging a rebellion in your stomach? It often comes down to a concept called osmolality. Think of it as the concentration of sugar and salt particles in the gel.

Most traditional energy gels are hypertonic, meaning they are far more concentrated than the fluids in your body. When this dense syrup hits your stomach, your body has to pull water from elsewhere to dilute it for digestion. This process is slow, inefficient, and the primary culprit behind cramping, bloating, and nausea, especially when you’re already dehydrated and blood is being diverted to your hardworking muscles.

It’s a perfect storm for digestive disaster. You’re asking a stressed system to handle a complex digestive task it’s ill-equipped for at that moment. The key to avoiding this is finding gels that are either formulated to be absorbed with less water or use carbohydrate sources that don’t trigger this intense osmotic reaction.

Maurten Gel 100: Hydrogel Tech for Smooth Fueling

Picture a gel that bypasses your stomach’s sensitive radar almost entirely. That’s the idea behind Maurten. They use a unique hydrogel technology made from two natural ingredients, alginate (from seaweed) and pectin.

When you consume it, the high acidity of your stomach instantly turns the liquid into a hydrogel, encapsulating the carbohydrates. This "jelly" then moves smoothly from the stomach into the intestine, where the water, salt, and carbs are absorbed. It’s a brilliant way to deliver a high concentration of energy without triggering the osmotic response that causes so much distress.

The tradeoff? Maurten is at the premium end of the price spectrum, and its texture is unlike any other gel—more like a loose, mildly sweet Jell-O. But for runners whose races have been ruined by GI issues, the cost is often a small price to pay for reliable, stomach-friendly fuel.

Huma Chia Energy Gel: All-Natural, Real Food Fuel

If the thought of consuming something created in a lab makes your stomach turn, Huma might be your answer. Born from the idea of the Tarahumara runners fueling with chia seeds, Huma gels are built on a foundation of real food: fruit purées, brown rice syrup, and ground chia seeds.

The all-natural formula avoids the maltodextrin that can be harsh for some athletes. The ground chia seeds are the magic ingredient here; they are hydrophilic, meaning they absorb water, which can help modulate the gel’s absorption and keep your hydration levels more stable. This results in a gentler, more food-like experience for your gut.

Be prepared for a slightly thinner consistency with a little bit of texture from the chia. It’s a fantastic choice for trail runners on long efforts or anyone prioritizing clean, simple ingredients. It feels less like a performance supplement and more like a high-octane snack.

SiS GO Isotonic Gel: No Water Needed for Digestion

On a hot, grueling race day, the last thing you want to do is force down a thick gel and then try to gulp down enough water to process it. Science in Sport (SiS) solved this problem with their GO Isotonic Gel. The key word is isotonic, meaning the gel’s concentration already matches the fluid in your body’s cells.

Because it’s already at the right concentration, your body doesn’t need to pull extra water into the gut to digest it. This allows it to empty from the stomach incredibly quickly, delivering fast energy without the risk of sloshing or bloating. You can take it on the run without immediately reaching for your water bottle, a huge advantage in the later stages of a race.

The practical consideration here is size. To achieve this isotonic state, the gels are larger and more watery than their competitors, taking up more space in your vest or belt. The flavors are also intentionally mild, which is a blessing for some but might feel underwhelming if you crave a sweet kick.

Spring Energy Awesome Sauce for a Balanced Recipe

Spring Energy takes a different approach to the "real food" philosophy. Instead of just focusing on simple sugars, their gels are formulated to be more like a balanced, liquid meal, often containing a mix of carbohydrates, healthy fats, and even a little protein.

Awesome Sauce, their flagship product, is made from basmati rice, applesauce, yams, and other whole foods. This blend provides a more complex and varied energy source that releases more steadily than a pure sugar gel. For many ultrarunners, this more holistic fuel feels much easier on the stomach over the course of a 50k or 100-miler, preventing the sharp peaks and valleys of simpler formulas.

This is not the gel for a quick, 5k burst of energy. It’s a workhorse fuel designed for long, steady efforts where you need sustained calories. The packets are larger, and the energy delivery is less of a "jolt" and more of a "slow burn," making it perfect for keeping your engine running smoothly for hours on end.

UCAN Edge for Steady, Slow-Release Carbohydrates

If you’re tired of the energy roller coaster—the spike of a traditional gel followed by the inevitable crash—UCAN Edge is designed to break that cycle. It’s built around a unique, patented corn starch called "Livsteady" that is fundamentally different from the simple sugars in most gels.

This complex carbohydrate breaks down very slowly, providing a steady, low-level release of glucose into your bloodstream over a longer period. This prevents the insulin spike that can lead to a bonk. Because it’s absorbed so steadily, it’s incredibly gentle on the stomach and doesn’t cause the osmotic issues of high-sugar gels.

UCAN is a proactive fuel, not a reactive one. You take it 30-45 minutes before a hard effort to pre-load your system with stable energy. It won’t save you when you’re already hitting the wall, but for marathoners and triathletes looking for consistent, crash-free performance, it’s a revolutionary tool. The texture is thicker, almost like a syrup or pudding, so be prepared for that.

Honey Stinger Organic Gel: Simple, Honey-Based Fuel

Sometimes, the simplest solution is the best one. Honey Stinger’s Organic Gels are built on a foundation of honey, nature’s original energy food. Honey is composed of fructose and glucose, two simple sugars that your body can absorb and use for energy very efficiently.

For runners who find complex, lab-engineered formulas like maltodextrin to be the source of their problems, this straightforward, organic approach can be a revelation. It’s just simple, effective fuel, supplemented with electrolytes and B vitamins to support energy production. It’s a trusted, no-frills option that has powered athletes for years.

Like any concentrated sugar source, it’s still best to take a Honey Stinger with a few sips of water to ensure smooth digestion. But its simple ingredient list makes it an excellent starting point for new runners or a reliable fallback for veterans who want to get back to basics.

How to Test and Choose Your Ideal Running Gel

The single most important rule of race fueling is sacred: nothing new on race day. Your long training runs are the perfect laboratory for dialing in your nutrition strategy. What works wonders for your running partner might be a disaster for you.

Start by picking one gel from this list that appeals to you, whether it’s the real-food approach of Huma or the high-tech formulation of Maurten. Try it 45-60 minutes into a medium-long run.

• Follow the directions: Does it say to take it with water? Do it.
• Pay attention to your body: How does your stomach feel? Any rumbling, cramping, or sloshing?
• Evaluate your energy: Did you feel a smooth boost, a sharp spike, or nothing at all?
• Simulate race conditions: Test your chosen fuel during a hard workout or on a hot day. Your gut behaves differently under stress.

The goal is to find a gel that gives you consistent energy, tastes good enough to eat when you’re exhausted, and, most importantly, keeps your stomach happy and quiet. Experiment, take notes, and trust what your body tells you. The perfect fuel is out there; you just have to find it.

Ultimately, the "best" gel is the one that disappears into the background, quietly doing its job so you can focus on your run. Don’t let the fear of GI issues keep you from fueling properly, and don’t get so obsessed with gear that you forget why you’re out there. Find what works, pack it in your vest, and go enjoy the miles.