Lucozade Sport Dual-fuel Energy Gels: How to Use Them for Marathon Fueling

By Ethan Brooks

Updated November 2026

Lucozade Sport dual-fuel energy gels are designed to deliver two different carbohydrate sources in one packet, which is meant to support steady energy during long runs. This guide explains what that dual-fuel approach means, how to fit the gels into a marathon or half-marathon fueling plan, and how to test them safely in training so there are no surprises on race day. Because product formulations and labels change, always check the packet you actually buy against the manufacturer’s current information.

What “Dual-Fuel” Means in an Energy Gel

Most energy gels rely on a single carbohydrate, usually maltodextrin, which is a glucose polymer that is broken down and absorbed quickly. A dual-fuel gel combines two carbohydrate types, typically glucose with a second sugar such as fructose. The idea is that the intestine can absorb more total carbohydrate per hour when different transport pathways are used at the same time. Research on exogenous carbohydrate oxidation has shown that combining glucose and fructose can allow higher intake rates than glucose alone for many athletes, though the benefit depends on the individual and how well their gut tolerates the load.

Shopping for one? See our guide: Science in Sport GO Isotonic Energy Gels Review: Is It Worth It?.

For a runner, the practical question is simple: does the blend let you take in carbohydrate at the rate your plan calls for without GI trouble? Check the carbohydrate grams per gel and the sugar blend on the label, then compare them to your target intake.

Step 1: Calculate Your Carbohydrate Target

Before you open a single packet, decide how much carbohydrate you want per hour. Many marathon fueling guidelines suggest roughly 30 to 60 grams of carbohydrate per hour for events lasting more than about 90 minutes, with some trained athletes working toward the higher end when their gut has adapted. Lower amounts are usually appropriate for shorter efforts or for runners who are still building tolerance.

Use this quick method to translate that target into gels:

1. Find the total carbohydrate grams in one packet from the nutrition panel.
2. Divide your hourly target by the carbohydrate per packet to get packets per hour.
3. Round to a practical schedule, such as one gel every 40 to 45 minutes.
4. Write the timing on your pace band or in your phone so you are not guessing mid-race.

Step 2: Build a Timing Schedule for Race Day

Gels work best when taken on a fixed schedule rather than only when you feel tired. Fatigue is a late signal, and carbohydrate absorption takes time, so waiting until you bonk means the gel will not help for a while. A common approach is to start taking gels after the first 45 to 60 minutes and then continue at regular intervals until the last 20 to 30 minutes of the race.

For a more detailed walkthrough of spacing and placement on the course, see When to Take Energy Gels: A Marathoner's Timing Guide. If you are racing a shorter event, When to Take Energy Gels During Half Marathon: A Step-by-Step Timing Guide covers how the schedule changes.

Treat these intervals as starting points. Your body weight, pace, heat, and gut tolerance all shift the right number, and the only reliable way to dial it in is through practice.

Step 3: Practice With the Gels in Training

Never try a new gel for the first time on race day. Gut tolerance is trainable but individual, and some runners experience cramping, nausea, or urgency when they take a new carbohydrate source at race pace. Use your long runs to test the product under realistic conditions.

A Simple Training Protocol

• Start with a half-dose in one long run to check for any GI reaction.
• If you feel fine, move to a full packet at your planned race intervals.
• Take the gel with the water you normally drink, and note whether the water intake feels adequate.
• Repeat the same protocol at least two or three times before race day so you can confirm the plan.
• Keep a short log of times, amounts, and how your stomach felt.

If you have a history of digestive problems, or you are managing a medical condition such as diabetes, consult a doctor or sports dietitian before changing your fueling strategy.

Step 4: Pair Gels With the Right Fluid

Gels are concentrated, so they need water to be absorbed and to avoid stomach upset. Plain water is usually the default, but some runners find that electrolyte drinks help with sodium replacement on hot days or in long events. Sip water with each gel rather than chugging a large volume at once. Many runners find that a few ounces at a time at each aid station is easier on the stomach than a big gulp.

Step 5: Adjust for Conditions and Your Own Response

Heat and humidity increase fluid and sodium losses, which can make gastric emptying slower and gels harder to tolerate. On hot days, some athletes space gels slightly further apart and rely more on fluids and electrolytes, while others keep the same carbohydrate schedule and monitor closely. Cold conditions can also affect how gels feel in your mouth and stomach, so warm the gel in a pocket or sip a little water first if needed.

Common Mistakes to Avoid

• Testing for the first time on race day. Always rehearse the exact product and schedule in training.
• Waiting until you feel depleted. By then, the gel will take time to help, so start on a schedule.
• Taking gels without water. Concentrated carbohydrate with little fluid can cause cramping and nausea.
• Changing brands mid-training. Switching products can change how your gut responds, so stick with one during your build-up.
• Ignoring the label. Carbohydrate content per packet varies between products, so recalculate if you switch.

Tips for Better Results

• Carry gels in a race belt or pocket where you can reach them without stopping.
• Take the first gel a little before a hill or a known fatigue point on the course.
• Save one packet as a backup in case of a dropped or damaged gel.
• Pair your gel schedule with the carbohydrate timing in your overall nutrition plan, including the pre-race meal.

Recommended gear

A few simple items make it easier to carry and take gels during a run. A small running belt keeps packets within reach so you are less likely to miss a scheduled fuel, which is especially useful in the middle miles where it is easy to forget.

• Race fuel belt: A slim belt with small pockets holds gels without bouncing, and many models include loops for a water bottle. View on Amazon
• Soft flask handheld bottle: A soft flask lets you sip a few ounces with each gel, which helps with washing the gel down. View on Amazon
• Gel holder clip or pocket insert: A small elastic loop or waistband clip keeps gels from shifting and makes one-handed opening easier. View on Amazon

FAQ

Are Lucozade Sport dual-fuel energy gels suitable for marathon running?

They can be, as long as you practice with them in training and fit the carbohydrate per gel into your hourly target. Check the current label for carbohydrate and sodium content before planning your schedule.

How many dual-fuel gels should I take in a marathon?

Many marathoners take three to four gels across the race, spaced roughly 35 to 45 minutes apart after the first hour. Your exact number depends on your pace, body size, and how much carbohydrate per hour you are targeting.

Should I take the gel with water or an electrolyte drink?

Water is the usual choice, with small sips at a time. Electrolyte drinks can help on hot days or in long events, but test the combination in training first.

Can I take gels before the race starts?

Some runners take a gel about 10 to 15 minutes before the start to top up carbohydrate, but this is individual. Rehearse it in training so you know how your stomach responds.

What if a gel upsets my stomach?

Reduce the amount, sip more water, or extend the interval between gels. If symptoms persist during training, consider a different carbohydrate source or speak with a sports dietitian.

Do I need gels for a half marathon?

Many half-marathon runners finish without gels, but those racing hard or running longer than planned may benefit from one or two. Practice first so you know whether it helps.

Can I use dual-fuel gels for training runs?

Yes, and this is where most gut training should happen. Using them on long runs lets you test timing, water intake, and tolerance under similar conditions to race day.

Are these gels appropriate if I have diabetes?

Carbohydrate needs and blood sugar responses vary, so consult your doctor or diabetes care team before using gels as part of a fueling plan.

Conclusion

Lucozade Sport dual-fuel energy gels can be a practical way to deliver carbohydrate during a long run or race, provided you plan the schedule around your own hourly target. Calculate your intake from the label, start taking gels before fatigue sets in, and rehearse the entire plan in training. Consistent practice, paired with water and a little patience, is what turns a gel from an experiment into a dependable part of your race day.

Related reading

• Science in Sport Isotonic Energy Gels: How to Use Them for Marathon Fueling

About Ethan Brooks

Ethan Brooks is part of our editorial team and reviews and edits our marathon & half-marathon guides, checking product details against manufacturer specifications and owner feedback.