Energy Gels

An energy gel, also called an energy gel or sports gel for endurance sports, is a concentrated, liquid carbohydrate source in a small sachet that you take directly and then wash down with water. The gel delivers quickly digestible carbohydrates that are available during high-intensity exertion without burdening the stomach with solid food. That makes a gel the most efficient way to replenish energy at a high heart rate: you do not have to chew, absorption is fast and the format fits in any running shorts pocket or rear jersey pocket on the bike. For training sessions or races longer than 60 to 90 minutes, an energy gel is the standard choice of endurance athletes to keep energy levels stable and to prevent the dreaded drop in performance in the closing stage.

The range runs from standard thick gels that you take with a sip of water to isotonic gels that can be taken without extra water, specialised polymer-based gels with minimal stomach load at high intensity, high-carb gels for athletes who deliberately take in more than 60 grams of carbohydrates per hour, and caffeine variants for a mental boost in the closing stage. For runners and triathletes, an isotonic energy gel is attractive because you do not have to carry a separate bottle for each gel; on the bike this matters less because drinking is part of the ride strategy anyway. The choice depends on your sport, your carbohydrate requirement per hour and how sensitive your stomach is during high exertion.

Which energy gel is there?

The range consists of four recognisable types, each with a different absorption technology, carbohydrate density or function.

Standard energy gels

The classic version: a thicker gel in a small sachet that you take with at least 100 to 150 ml of water. Standard gels deliver an average of 20 to 27 grams of carbohydrates per sachet, mainly from maltodextrin and glucose, and are broadly usable in training sessions and races of varying duration. They are available with and without caffeine. With standard gels it is important to always drink enough water when taking them: without water, gastric emptying slows down and gels can cause stomach complaints at high intensity.

Isotonic energy gels

Gels that are formulated isotonically, which means they have the same osmotic pressure as blood and can therefore be taken without extra water. They have a thinner consistency than standard gels and contain fewer carbohydrates per gram (usually 20 to 22 grams per 60-gram portion), but the low concentration makes direct absorption without water possible. That is a practical advantage for runners who do not carry a bottle and for moments in a race or training session when no water is available.

Polymer- and hydrogel-based gels

Gels that make use of specialised carbohydrate polymers with a high molecular mass. Due to the higher molecular mass, the gel has a lower osmotic pressure than standard gels at a comparable carbohydrate content, so gastric emptying is barely slowed down. These gels are specifically developed for use at high intensity where stomach and intestinal comfort at a high heart rate is the critical point of attention. They are taken with water and contain no artificial flavours or colourings. They are available with and without caffeine and in variants with a higher carbohydrate concentration.

High-carb and high fructose gels

Gels with a higher carbohydrate density of 40 to 50 grams per portion, specifically intended for athletes who follow an intake strategy of more than 60 grams of carbohydrates per hour. They combine glucose and fructose in a ratio of 1:0.8 or higher for maximum absorption via multiple intestinal enzymes. Choose high-carb gels if you have trained intestines that can handle higher carbohydrate intake and you are deliberately working on a structured nutrition strategy for triathlons, marathons or long stage races. Not recommended for athletes who have not yet tested gels and high carbohydrate intake per hour in training.

Caffeine gels

Each type mentioned above is also available in a caffeine variant, usually with 50 to 100 mg of caffeine per gel. Caffeine lowers perceived exertion and increases alertness. Strategic use is the key: a caffeine gel is most effective in the last 30 to 45 minutes of a race or during an intensive effort where mental fatigue plays a role. Do not use caffeine gels in every training session; save them for races and crucial training sessions to limit habituation.

Which energy gel suits you?

The choice depends on your sport, the duration of your effort and how sensitively your stomach reacts to concentrated sugars at a high heart rate.

You are running a half marathon, marathon or a longer running training session: choose an isotonic gel for the first gels along the way and a caffeine gel for the final kilometres. Isotonic gels can be taken without a bottle, which is practical when running. Take the first gel around 45 to 60 minutes and repeat every 20 to 30 minutes depending on the pace. Always test your gel strategy on long training runs at race pace before applying it on race day.

You are riding a long bike ride, stage race or triathlon and want maximum carbohydrate intake: consider a combination of high-carb gels and an isotonic sports drink in your bottle. On the bike you can easily drink at every feed station or from your bottle, so the water problem of standard gels disappears. Use high-carb gels if you need replenishment on top of the carbohydrates you already get through the sports drink. Make sure the combined intake per hour is realistic for your stomach capacity.

You have stomach problems with gels at high intensity: choose polymer-based gels and always take them with enough water. Stomach problems with gels can in most cases be traced back to one of three causes: too little water when taking them, too high a concentration of carbohydrates per gel, or too high a total intake per hour. Polymer gels solve the first two problems through a lower osmotic pressure at a comparable energy content.

You do triathlon and want to carry as little as possible on the running section: choose isotonic gels or liquid gels that you can hold in your hand or tuck into a rear pocket without an extra bottle. On the cycling part you replenish most of the carbohydrates; the running part only requires one or two gels depending on the distance. Leave standard thick gels out of the run if you would have to carry extra water for them: simplify your strategy for the run.

You are trying an energy gel for the first time and do not know which type suits you best: buy a trial pack or single sachet of several types and test them in training. Start with an isotonic gel on a quiet endurance run of 75 to 90 minutes and assess how your stomach reacts to the pace. If you have no complaints, you can then test standard gels and high-carb variants on comparable training sessions. Never try them out for the first time on race day. Also take a look at the complete sports nutrition range for an overview of all options besides gels.

Isotonic gel or standard gel?

This is the most practical choice for new gel users. The difference in use is smaller than it sounds, but in specific situations it is relevant.

A standard gel has a high sugar concentration that slows down gastric emptying if too little water is taken with it. The rule of thumb is: drink at least 150 ml of water with each gel, preferably 200 ml. On the bike this is no problem; you drink regularly anyway. When running without a bottle, it depends on the running route whether water points are available.

An isotonic gel is formulated so that it has the same concentration as blood, so it can be absorbed without extra water. Disadvantage: per gram of product there is less carbohydrate, so you take in a larger volume per portion for the same amount of energy. For sensitive stomachs, isotonic gels are usually gentler. When running without water points, they are safer than standard gels.

Choose a standard gel if you do a sport where water is always available and you have little stomach sensitivity. Choose an isotonic gel if you run without water points at fixed intervals, have a sensitive stomach at high intensity, or prefer a thinner product that is easier to wash down.

What do you look out for with energy gels?

Carbohydrate content and type

Standard gels deliver 20 to 27 grams of carbohydrates per sachet. High-carb gels 40 to 50 grams. Choose the content based on your intake strategy per hour: with a target of 60 grams per hour via gels alone, you need a standard gel every 20 minutes. With a combination with a sports drink, you can take in fewer gels. Carbohydrate type is also relevant: gels with only glucose or maltodextrin are limited to 60 grams of absorption per hour; gels with glucose-fructose combinations allow a higher absorption for athletes with trained intestines.

Water intake with each gel

One of the most common mistakes with gel use is taking them without enough water. With standard gels, too high a sugar concentration draws fluid from the intestinal wall into the intestinal contents, which slows down absorption and can cause diarrhoea or stomach pain at a high heart rate. Take at least 150 ml of water with each standard gel. Take isotonic gels without extra water or with a small amount of water. Always take polymer gels with water as indicated on the packaging: the minimum amount is usually stated there.

Caffeine timing and dosage

Caffeine has its peak effect 45 to 60 minutes after intake. Therefore take a caffeine gel 45 minutes before the moment at which you want the effect: in a marathon that is the last 10 kilometres, in a triathlon the last half of the run. Add up caffeine intake across all sources: if you combine caffeinated gels with caffeinated sports drinks or bars, the total intake is quickly higher than optimal. Aim for 100 to 200 mg of caffeine in the closing stage; more does not lead to extra performance gains for most athletes but does lead to an increased risk of heart palpitations or stomach problems.

Taste and consistency during fatigue and high heart rate

At high intensity, taste perception changes. Gels that taste good at rest can feel too sweet, too sticky or too heavy at a high heart rate. Always test gels in training at race intensity, not at rest. Choose a neutral or sour flavour if you know from experience that sweet flavours go down less well during high exertion. Liquid gels with a thinner consistency are easier to take for some athletes during fatigue than traditional thick gels.

Our advice: start with an isotonic gel if you run and a standard or polymer gel if you cycle or do triathlon where water is always within reach. Test each gel several times in training at the intensity of your race goal before using it on race day. The combination of a reliable standard gel for the largest part of the effort and a caffeine variant for the closing stage is the most effective and proven strategy for most endurance athletes. Buy in bulk packs once you have found one type that works well: the price per portion drops considerably.

Who are energy gels suitable for?

• Runners who need a compact, easy-to-carry carbohydrate source without a bottle or solid food during training sessions and races longer than 60 to 90 minutes, with a preference for isotonic gels that can be taken without extra water.
• Triathletes who want to keep their energy up on the running section of a triathlon with minimal weight and volume, and who use a combination of gels and sports drink on the cycling section for maximum carbohydrate intake.
• Cyclists who, besides a sports drink, also carry a compact gel option for the closing stage of a ride or race when eating a bar becomes too awkward and a quick boost is needed.
• Athletes with stomach sensitivity to regular sports nutrition who benefit from polymer gels or isotonic formulas that put less load on the stomach at a high heart rate than standard gels or solid food.
• Beginners switching from water only to structured sports nutrition and looking for an accessible, immediately effective product for their first long training sessions and races above 90 minutes.

Need help with your choice?

Would you like to buy energy gels but are you not yet entirely sure which type and which formula best suits your sport and nutrition strategy? Then we are happy to help you further. You can reach our triathlon specialists by phone via +31 (0)413-256800, send an email or drop by our triathlon shop in Volkel, the Netherlands.

Frequently asked questions about energy gels

When do I take an energy gel during exercise?

Take the first gel around 45 to 60 minutes after the start of the effort, before you experience a noticeable drop in energy. Waiting until you are exhausted is too late: the carbohydrate stores are then already so low that recovery at high intensity is more difficult. Repeat the intake every 20 to 30 minutes depending on intensity and the type of gel you use. Always take gels with enough water, including isotonic gels if you want to support the intake.

How many energy gels do I take with me for a marathon or triathlon?

For a marathon you count on an average of one standard gel per 20 to 30 minutes for a total duration of 3 to 5 hours, which amounts to 5 to 10 gels depending on your pace and combination with a sports drink on the running course. For a triathlon you spread the gels over the cycling and running section: you take most gels on the bike, the run requires 1 to 3 gels depending on the distance. In races, always take one or two extra gels with you as a reserve.

What is the difference between an energy gel and an energy bar?

An energy gel is a liquid concentrate that you take directly without chewing and that is absorbed quickly at high intensity with minimal stomach load. An energy bar is a solid product that you chew and that is more digestible at lower intensity or in the quieter part of a ride. At a high heart rate gels are the better choice; at rest or a lower pace bars can give more satiety. Many athletes combine both: energy bars in the first hour, gels in the closing stage or at higher intensity.

Can I take energy gels if I am not into top-level sport?

Yes, but energy gels are only useful for efforts longer than 60 to 90 minutes at a moderate to high pace. With shorter training sessions or walking, the glycogen stores are amply sufficient and a gel does not deliver a performance difference. Recreational athletes who regularly do longer training sessions (running training sessions of 75 minutes or more, bike rides of 2 hours or longer) benefit from gels for maintaining energy levels. Isotonic gels are usually the most pleasant entry point for beginners because they can be taken without water and have a lower risk of stomach complaints.

Can energy gels cause stomach problems?

Energy gels can cause stomach problems if they are taken without enough water (with standard gels), if the total carbohydrate intake per hour is too high for the training status of the intestines, or if the gel is used for the first time in a race without prior tests in training. Most problems can be avoided by always drinking enough water when taking them, building up the amount per hour gradually and testing new products several times in training at race intensity. Athletes with a structurally sensitive stomach benefit from polymer gels or isotonic variants that put less load on the stomach at high intensity.