Are Energy Gels Good for Running?

You're 20 kilometres into a long run. Your legs are still moving but something has shifted — pace feels harder than it should, your stride is shortening, and you're spending energy you don't feel you have. That is not always a fitness problem. Often it's a fuel problem that started 40 minutes earlier when you took nothing in. By the time it registers, you're already reacting.

That's the real question behind "are energy gels good for running?" Not whether gels exist, but whether you're using them correctly — and early enough to matter.

For most runners doing sessions beyond 75 minutes, or any race distance from half marathon upwards, gels are one of the most reliable tools available. They deliver fast-absorbing carbohydrate in a format you can take on the move, at pace, without needing to chew. Whether they work depends on which gel you choose, how much carbohydrate it actually delivers, and whether you've built a timing plan around them rather than guessing.

"When I was developing the truefuels gel, the number that mattered most wasn't flavour or texture — it was 40g. That's the carbohydrate dose that actually moves the needle for endurance performance. Most gels deliver 20-25g and call it a serving. That forces athletes to carry twice as many and still fall short."
— Alistair Brownlee, Two-time Olympic Triathlon Champion and founder of truefuels

Are energy gels good for running, really?

Yes — in the right context. During harder or longer running, your body relies heavily on carbohydrate. Muscle glycogen stores are finite. Once they start to run low, pace drops, effort perception rises and decision-making deteriorates. That's the fade most runners describe as bonking — and it's preventable.

Energy gels work because they deliver fast-available carbohydrate in a compact format. The best ones are specifically designed to be easy to open under race stress, easy to swallow at high breathing rates, and predictable on the stomach. That last point matters more than most runners appreciate. When you're 30km into a marathon, simplicity and reliability are everything.

For shorter, easier runs — anything under 60 minutes at conversational pace — gels are generally unnecessary. Your pre-run meal is usually enough. Where they become genuinely valuable is when duration, intensity or both increase.

What separates a performance gel from a convenience gel

Not all gels are equal, and the difference is measurable.

The key variable is carbohydrate per serving and the ratio of carbohydrate sources. Most gels use glucose as the sole carbohydrate. The problem with that is glucose is absorbed through a single intestinal transporter — SGLT1 — which saturates at around 60g per hour. Take more than that from glucose alone and the excess sits in the gut.

The solution, backed by 13C oxidation research on elite athletes, is a 1:1 glucose-to-fructose ratio. Fructose is absorbed through a completely separate transporter — GLUT5 — so both pathways run simultaneously. That means absorption capacity rises to 90–120g of carbohydrate per hour without the gut distress that comes from overwhelming a single transporter.

The truefuels Performance Gel delivers 40g of carbohydrate per serving in a 1:1 ratio, with electrolytes built in — 250mg or 1,000mg of salt depending on variant, plus 288mg natural potassium and 30mg magnesium. Most competitor gels contain none. That matters because sodium also enhances carbohydrate absorption via the SGLT1 co-transporter. It earns its place twice.

Gel comparison by carbohydrate dose and electrolytes

The practical consequence: with most gels you need 4–5 per hour to approach 90–120g of carbohydrate. With truefuels, 2–3 does it — less to carry, less to manage, less flavour fatigue over three or four hours.

When gels make sense for runners

The answer depends on the session.

Gels are especially valuable in three situations: when the run is long enough to deplete stored carbohydrate, when intensity is high enough that carbohydrate use rises sharply, and when carrying solid food is impractical at pace.

The gut issue — and why it's usually protocol, not product

Gels are good for running, but not every runner tolerates every gel. The gut is under stress during exercise — blood flow diverts to working muscles, temperature rises, and concentrated carbohydrate without enough fluid can cause sloshing, cramps or nausea.

That is often a protocol failure, not a product failure. Taking a gel too late, taking too much at once, using products you've never trained with, or ignoring fluid intake can all produce avoidable problems. The truefuels gel's fluid texture helps — it's water-mixable, easy to swallow at high respiratory rates, and contains no artificial sweeteners, preservatives or emulsifiers that typically aggravate GI issues.

How many gels do you actually need?

The carbohydrate target that matters for performance is 60–90g per hour for most endurance athletes, rising to 90–120g per hour for trained athletes in longer events. At 40g per truefuels gel, the maths is straightforward:

• 60g/hour = 1 x 40/1.0 gel + supplement from other sources, or 1.5 gels (round to 2)
• 80g/hour = 2 gels
• 90–120g/hour = 2–3 gels

Start early. Take your first gel within 20–30 minutes of a long run or race start, then maintain even spacing. The most consistent mistake runners make is waiting until they feel empty — by then, performance has already slipped.

Common mistakes runners make with gels

Underfuelling because it feels disciplined. It isn't. Running on empty doesn't build toughness. It produces sub-quality training and slower racing.

Using gels as rescue fuel rather than planned fuel. Once legs feel hollow and the mind goes foggy, you're 15–20 minutes behind your fuel deficit, not on top of it.

Ignoring tolerance. If a product repeatedly causes stomach issues, forcing it through a training block is poor decision-making. Test in training. Change variables one at a time.

Separating fuelling from hydration. Endurance performance doesn't work in separate boxes. Carbohydrate intake, fluid strategy, sweat losses and environmental conditions all interact. The truefuels gel's built-in electrolytes are designed to address this — so that your sodium, potassium and magnesium are covered without needing a separate product for every session.

So, are energy gels good for running?

For serious runners — yes, when the run is long enough, hard enough or important enough to justify them. They're one of the most practical ways to maintain carbohydrate intake during exercise, protect pacing and reduce the risk of a late-race energy collapse.

The best results come not from the gel alone, but from using the right amount, at the right time, with the right fluid, in a plan you've already tested. Forty grams of carbohydrate per gel isn't just a number. It's the difference between running your race and surviving it.

If you want your fuelling to hold up when the race asks real questions, don't wait for a bad patch to build your protocol. Build it in training, when the consequences of getting it wrong are smaller.