Running Gels Explained — What They Are, How They Work, and When to Use Them

Running gels are portable, fast-digesting energy sources designed for endurance athletes who need quick fuel during prolonged activity.

While they're most popular among runners, cyclists, triathletes, and team-sport athletes also rely on them to maintain performance when exercise pushes beyond the 90-minute mark.

Take RPG Endurance & Energy Gels by VPA® - a great example of modern running gels formulated for performance across all endurance sports. With options for both caffeinated and non-caffeinated varieties, they deliver the carbs you need when you need them.

Below, we'll cover what energy gels are, how they work, when to take them, their benefits, and how to choose the right one for your goals.

Running gels (also called energy gels or endurance gels) are concentrated carbohydrate packets. They're portable emergency fuel you can stash in your pocket. Small sachets, easy to open mid-stride, designed to hit your system fast when you're deep into a long effort.

During extended exercise, your body burns through glycogen - that's stored carbohydrate in your muscles and liver. It's your primary fuel tank for anything above moderate intensity. The problem? Research shows liver glycogen gets substantially depleted around the 90-minute mark 1 during continuous exercise. Running gels help you top up those stores while you're still moving, keeping your energy steady instead of watching it crash.

Now that you know what energy gels are, here are the key ingredients most running gels contain:

• Simple carbs (glucose, maltodextrin, fructose) for fast digestion

• Electrolytes like sodium and potassium, since you're sweating them out

• Caffeine in some versions for mental sharpness

• Sometimes amino acids or added vitamins

An effective gel typically delivers 20-30g of carbohydrates per serving. The better ones mix fast-acting and moderate-release sugars together. Some run a glucose-to-fructose ratio (like 2:1), which studies show can enhance carbohydrate oxidation rates and reduce that heavy, upset stomach feeling.

We made RPG Endurance Gels with exactly this balance in mind - clean energy, nothing you don't need.

When you tear open a gel and have it mid-run, this is what happens: carbs get absorbed through your digestive system and converted into glucose. That glucose hits your bloodstream, gets transported to your working muscles, and gets converted into adenosine triphosphate (ATP) - which is the technical way of saying "the energy currency your muscles actually use to contract."

Does this actually help? Yes. Research consistently shows that consuming 30-80g of carbohydrate per hour enhances endurance performance 3 in adults. Not placebo, not marketing - measurable improvement in time trials and time to exhaustion. For ultra-endurance events (longer than 2.5 hours), the data points to even higher rates working well, sometimes 60-90g per hour.

Not all carbs absorb the same way, though. Gels with multiple transportable carbohydrates like glucose plus fructose can support higher absorption rates than single-source gels. 5 Your body uses different pathways for different sugars, so combining them means you can actually get more fuel in without overwhelming your gut.

Gels typically kick in 5-15 minutes 6 after you take them. Speed varies based on gel type and how hydrated you are. Isotonic gels (formulated to match your body's fluid concentration) absorb faster since they need less water to process.

The real strategy? Don't wait until you're cooked. Take a gel every 30-45 minutes during long efforts. By the time fatigue properly hits, your glycogen's already dangerously low and recovering becomes way harder than just maintaining. Prevention beats cure, any day.

Taking a gel 10-15 minutes before you start can give you that early boost. This works especially well if you're training fasted or hitting an early morning session. Just don't make the mistake of taking gels 1-2 hours before without actually exercising, you might trigger an insulin response that leaves you flat when you actually need energy.

This is where running gels work well. Any endurance session pushing past 60-90 minutes? You need to be supplementing. Gels help maintain blood glucose and spare your glycogen stores. Start early, around the 30-45 minute mark, before fatigue even shows up.

We offer RPG Endurance Gels in caffeinated and non-caffeinated versions for exactly this reason. Maybe you're training at 5 am and don't want the extra stimulation. Non-caffeine. Maybe it's race day and you need that mental edge - caffeine. Caffeine doses of 3-6mg per kilogram body mass have been shown to improve endurance performance, 7especially in aerobic activities.

For events longer than 2-3 hours, target 60-90g carbs per hour. Split it between gels, drinks, whatever sits well in your stomach.

Gels aren't designed for recovery, but they work if that’s all you’ve got. Finish a hard effort with no food access? A gel within 30-60 minutes post-exercise helps kickstart glycogen replenishment. But honestly, whole foods with protein are better for recovery. Gels are for during, not after.

Most endurance gels, especially hypertonic ones (higher sugar concentration), need water to absorb properly. We're talking 200-300ml of water 6 per gel. Without it, the gel just sits heavy in your gut.

Isotonic gels like RPG can be taken with less water or even on their own since they match your body's fluid concentration. But staying hydrated throughout your session improves performance and comfort regardless of gel type.

Never, and we mean never, try new running gels on race day. Your gut needs adaptation time. Practice your fuelling strategy during long training runs or rides. Figure out which flavours work for your stomach, make a comfortable intake schedule, train your digestive system to process fuel under stress, and avoid surprises when you're chasing a PB.

Just as you wouldn't race in brand new trainers, the same applies to gels - test everything in training first.

The main reason anyone uses running gels? Performance. Plain and simple. Research consistently shows that carbohydrate intake during endurance exercise improves time trial performance and increases time to exhaustion compared to taking nothing. 3 We're not talking placebo effects here - this is measurable, repeatable improvement.

What you'll notice:

• No more hitting the wall

• You can hold target pace longer without fading

• Mental focus stays sharper (your brain runs on glucose, too)

• Recovery between efforts improves (useful for multi-stage events)

Beyond just carbs, quality endurance gels include electrolytes to maintain hydration balance and help prevent cramping. Some formulas throw in branched-chain amino acids (BCAAs) or B vitamins to support energy metabolism.

That said, let's be clear: gels are excellent supplements for runners and endurance athletes, but they work best alongside a balanced diet. Lean proteins, nutrient-dense carbs, whole foods - that foundation matters. Gels fill the gap during exercise, not the rest of your nutrition.

More doesn't always equal better. Having too many endurance gels in a short window overwhelms your digestive system. You'll end up with bloating, cramping, or nausea instead of energy. Stick to 1-3 gels per hour, depending on how long you're out there and how intense the effort is. Balance them with other carb sources if you need more fuel.

Gels without adequate water just sit there, heavy in your gut, slowing down absorption. Always have water on hand. This goes double during hot conditions or high-intensity efforts where you're sweating buckets.

Your gut is trainable, and that's not just marketing talk. Athletes who regularly consume carbs during training experience way fewer stomach issues than those who only fuel during races. Build up your tolerance gradually over time. Your stomach will adapt.

By the time proper fatigue hits, you're already behind. Your glycogen's low, your performance is dropping, and clawing back becomes a battle. Start fuelling early and maintain consistency throughout.

For sessions under 60 minutes, your body's stored glycogen is usually enough. Save the endurance gels for longer efforts where they'll actually make a difference. No point fuelling when you don't need it.

No. Not even close. Despite the name, running gels work for any sustained endurance activity. Cyclists on century rides, triathletes grinding through swim-bike-run, adventure racers in multi-day events, cross-country skiers, team-sport athletes in back-to-back tournament games - all benefit from portable, fast-acting carbs.

We built RPG Endurance & Energy Gels for sustained performance across all endurance sports, not just running. It doesn’t matter if you're logging kilometres on foot, going for a long ride, or competing across multiple days, the fuelling principles stay the same.

With so many options out there, picking the right gel comes down to a few factors:

• Carbohydrate content:

Look for 20-30g per serving. That's the effective range for most endurance needs.

• Carb source:

Multiple transportable carbs (glucose + fructose) work best for high intake rates. Your body absorbs more total fuel this way.

• Osmolality:

Isotonic gels empty faster from the stomach and need less water. Less gut discomfort.

• Caffeine:

Decide if you want stimulation or prefer non-caffeinated for late training sessions. Both work.

• Flavour and texture:

Personal preference matters. Pick something you'll actually want to consume repeatedly mid-effort.

• Ingredients quality:

Avoid unnecessary additives, artificial colours, or proprietary blends that hide amounts. You should know what you're consuming.

Our approach at VPA: 100% transparency, quality ingredients, and formulations backed by sports science. No secrets, no shortcuts.

Generally safe, but some athletes experience side effects:

• Stomach upset or cramping (usually from high sugar concentration or insufficient water)

• Nausea (from consuming too many gels too quickly)

• Jitteriness or anxiety (from caffeinated gels if sensitive)

• Blood sugar spikes and crashes (if using them outside exercise - don't)

Safety tips:

• Start with half a gel if new to fuelling

• Always practice in training before race day

• Stay hydrated throughout sessions, not just when taking gels

• Consult your doctor if you have diabetes or blood sugar concerns

• Choose caffeine-free versions for late-day exercise or if sensitive to stimulants

• Check labels for allergens if you have dietary restrictions

Keep in mind: Gels support performance alongside proper nutrition. They're not meal replacements.

Running gels are powerful performance tools when used correctly. Start fuelling early, maintain consistency every 30-45 minutes, stay hydrated, and always practice your strategy in training before race day.

Whether you're chasing a PB, tackling your first marathon, or want to feel stronger during long sessions, understanding what energy gels are and how to properly use them gives you a genuine competitive edge.

VPA's RPG Endurance & Energy Gels are designed with transparency and performance in mind - delivering the fuel you need without the guesswork.

Try them during your next long session and feel the difference for yourself.