What Energy Gel Should You Use, and When?

2nd Oct 2026

The best energy gel depends on your race duration, intensity, conditions, and individual tolerance. For half-marathons and marathons, aim for 90–120 g of carbohydrate per hour, while longer events may require higher intake with appropriate electrolyte or caffeine products. Choose a gel that suits your needs and always test it during training before race day.

Key Takeaways

Start fuelling within the first 30–45 minutes of any endurance effort, and maintain a consistent gel cadence rather than waiting until fatigue sets in.
Match gel type to the event: isotonic for limited-water situations, electrolyte for heat, caffeine or nootropic gels for a late push or pre-race boost.
Target roughly 60g of carbohydrate per hour for one-to-two-hour efforts, rising to 90–120g/hour for longer events using a dual-source (multiple transportable carbohydrate) formula.
Never test a new gel, timing approach, or volume on race day; practise the full plan in long training sessions first.
Pair gel strategy with adequate hydration; carbohydrate absorbs more efficiently when fluid levels are maintained.
Science in Sport states that its Australian products are Informed Sport registered; verify the exact product and batch before use.

Why Do Energy Gels Matter in Endurance Sport?

Carbohydrate is the body's primary fuel source during sustained exercise, stored as glycogen in the muscles and liver, and those stores are limited. Beyond about 90 minutes, glycogen falls and pace tends to drop faster than most athletes expect. Energy gels address this by supplying a concentrated, portable carbohydrate source that maintains blood glucose and preserves glycogen without the bulk of whole food, which is why many endurance athletes who under-fuel close that gap with a planned gel strategy.

What Is the Difference Between Standard, Isotonic, and Dual-Source Gels?

Standard gels use maltodextrin and glucose for rapid carbohydrate delivery and are typically taken with water. Isotonic gels, such as SiS GO Plus Isotonic Energy Gels, are formulated to match the concentration of dissolved particles (osmolality) in body fluids, so they can be absorbed without extra water, useful when hydration access is limited or intensity is high. Gels built on multiple transp ortable carbohydrates combine glucose polymers with fructose, engaging two separate intestinal absorption pathways at once, which allows up to roughly 120g of carbohydrate per hour versus around 60g from glucose alone, with less GI discomfort. The BETA Fuel range uses this approach, at a 1:0.8 maltodextrin-to-fructose ratio.

Gel Type	How It Is Absorbed	Best Use Case
Standard (maltodextrin/glucose)	Single intestinal pathway	Simple, familiar, best taken with water
Isotonic (e.g. GO Plus Isotonic)	Matched osmolality to body fluids	Limited water access or high-intensity efforts
Dual-source (e.g. BETA Fuel, 1:0.8 ratio)	Two intestinal pathways at once	Higher carbohydrate delivery (up to ~120g/hour) with less reported GI distress
Caffeine / nootropic (e.g. BETA Fuel + Nootropics Gel, GO Caffeine Shot)	Carbohydrate base plus caffeine and/or nootropics	Late-race focus and reduced perceived effort

How Much Carbohydrate Do You Need, and When Should You Start, by Event Length?

Event Duration	Carbohydrate Target	Fuelling Approach
Under 1 hour	Often none needed at moderate intensity	A small gel near the 30-minute mark helps in demanding conditions or at high pace
1.5–4 hours (half marathon to marathon)	60–90g/hour	Start within 30–45 minutes, then roughly every 20–30 minutes
4+ hours (ultra-endurance)	90–120g/hour	Rotate high-carbohydrate, electrolyte, and caffeine gels; prioritise dual-source products

The Australian Institute of Sport publishes research-backed guidance on carbohydrate supplementation in endurance sport for athletes who want the underlying evidence base.

How Do Race Conditions Affect the Best Gel Choice?

In heat or high humidity, sweat losses rise, so gels containing sodium and electrolytes help replace minerals and reduce cramping risk; pairing them with a hydration product such as electrolyte powder or hydro tablets supports the fluid balance that carbohydrate absorption depends on. On hilly or trail courses with a higher digestive load, isotonic gels tend to work better since they need less water and sit more gently on the gut. Late in a long event, a caffeine or nootropic gel helps maintain focus through the closing kilometres, taken in the first half of the race so it has time to fully absorb before the toughest stretch.

How Should You Build and Test a Gel Fuelling Plan?

A gel plan works best once it has been practised; introducing a new product, formulation, or timing on race day is one of the most common causes of gut distress. Long training sessions are where habits, tolerance, and flavour or texture preferences get confirmed. Time-based cues work better than waiting until fatigue sets in, with every 20 minutes a common starting point; timing a gel just before a water station and carrying one spare in case the event runs long are both practical habits. After each session, noting how the stomach responded and when energy felt strongest builds a clearer picture over time. Sports Dietitians Australia publishes practical guidance on carbohydrate intake for endurance athletes for runners refining this further.

What Are the Key Principles for Choosing an Energy Gel?

Choosing the right energy gel comes down to three factors: how much carbohydrate the event demands, the conditions you will be racing in, and how well your gut handles the product. Testing gel type, timing, and intake in training, not on race day, is what turns those three factors into a plan that actually holds up.

Fuel Your Next Endurance Event with Science in Sport

Ready to put your gel strategy into action? Start with these:

Have questions about your fuelling plan? Check our shipping and returns information before your next order.

Frequently Asked Questions

1. What is the best energy gel for endurance running?

It depends on race duration and tolerance. For events over two hours, dual-source gels like BETA Fuel Gel allow higher carbohydrate absorption with less GI distress. For shorter or moderate efforts, isotonic gels from the GO Plus range are a practical, well-tested option.

2. When should I take my first gel during a race?

Start within the first 30–45 minutes, well before feeling hungry or tired. Waiting until fatigue sets in means blood glucose has already begun to fall, making it harder to recover mid-race.

3. What is the difference between isotonic and standard energy gels?

Isotonic gels can be taken without extra water, while standard gels are more concentrated and best taken with water. Testing both in training identifies which works best for a given athlete.

4. How many gels do I need for a marathon?

For a marathon lasting 3–5 hours, most runners need 5–9 gels depending on pace, body weight, and conditions, roughly one every 20–30 minutes from the 45-minute mark, to reach 90–120g of carbohydrate per hour.

5. Should I use a caffeine gel before or during a race?

Both work depending on race length. For events under 90 minutes, a caffeine gel around 30 minutes before the start sharpens focus from the outset. For longer events, taking it in the first half means it is fully absorbed before the critical later stages.

6. What causes gel-related stomach problems during a race?

Common causes include taking gels too late once the gut is already stressed, large amounts without enough fluid, unfamiliar products on race day, or formulations poorly tolerated at high intensity. Gut training, practising the full plan in long training sessions, addresses this directly.