What is the world's first isotonic energy gel?

December 13, 2025 •

4 min read

Depleting carbohydrate stores is a leading cause of fatigue in endurance sports. The solution arrived in a unique form when Science in Sport (SiS) developed what is the world's first isotonic energy gel, creating a new standard for easily digestible and effective on-the-go fueling for athletes.

Quick Summary

The SiS GO Isotonic Energy Gel was the first of its kind, delivering quick carbohydrates to athletes without requiring water for absorption. Its unique formula prevents stomach upset and speeds up energy delivery for enhanced performance during exercise.

Key Points

Origin: The SiS GO Isotonic Energy Gel is the world's first isotonic energy gel, developed by Science in Sport in 1997.
Isotonic Science: The gel's formula matches the concentration of body fluids, allowing for rapid absorption without needing extra water.
Digestion Benefits: The isotonic nature prevents water from being pulled into the stomach, minimizing bloating and cramps during exercise.
Enhanced Convenience: Eliminating the need for a separate water source simplifies an athlete's fueling strategy, especially during a race.
Performance Impact: Faster absorption means carbohydrates reach working muscles more quickly, helping to delay fatigue and improve endurance.
Award-Winning Innovation: The development was so significant it earned the Queen's Award for Enterprise in 2015.
Widespread Use: The technology continues to be a standard for endurance athletes and has influenced the development of many subsequent products.

The Groundbreaking History of the Isotonic Gel

Before the late 1990s, energy gels were a messy and often indigestible affair. These traditional, hypertonic gels contained a high concentration of carbohydrates, which required athletes to drink additional water to aid absorption. Failing to do so could pull water from the bloodstream into the stomach, causing bloating, cramps, and other gastrointestinal distress—a significant hurdle for athletes seeking to maintain performance. Recognizing this problem, the research and development team at Science in Sport (SiS) sought a better way to fuel endurance athletes.

In 1997, SiS launched the GO Isotonic Energy Gel, marking a pivotal moment in sports nutrition. The innovative product was designed with an osmolality (a measure of solute concentration) that was very similar to the body's own fluids. This breakthrough meant the gel could be consumed without extra water, allowing it to pass quickly from the stomach into the small intestine for rapid absorption. The innovation was so significant that it later won the Queen's Award for Enterprise in 2015. The SiS GO Isotonic Energy Gel was a game-changer, providing a convenient, fast-acting, and stomach-friendly fuel source that elite and amateur athletes worldwide continue to rely on today.

The Science Behind Isotonic Formulation

Understanding how an isotonic gel works requires a basic grasp of tonicity and osmosis. Solutions can be categorized as hypotonic, isotonic, or hypertonic based on their concentration relative to the body's cells.

Hypertonic: Higher concentration than body fluids. This is characteristic of traditional energy gels, which force the body to draw water from its cells into the stomach to dilute the solution for absorption. This can cause dehydration and stomach issues.
Hypotonic: Lower concentration than body fluids. Hypotonic solutions empty from the stomach very quickly but don't carry a high density of energy.
Isotonic: A matched concentration to body fluids. The SiS GO gel's maltodextrin formula creates this balanced solution, eliminating the need for extra water and allowing for swift, gentle digestion and rapid energy delivery.

This scientific approach allows the carbohydrates to be used by the muscles more efficiently, delaying fatigue and improving endurance performance.

Key Advantages of SiS Isotonic Gels

The adoption of the isotonic format provided a host of benefits that set it apart from its predecessors and competitors:

Faster Absorption: The formulation promotes quicker gastric emptying, meaning the carbohydrates are delivered to the muscles with minimal delay.
Reduced Gastrointestinal Stress: By not requiring additional water for dilution, the gel minimizes the risk of bloating and stomach discomfort, which can be detrimental to performance, especially during long races.
Enhanced Convenience: The ability to consume the gel without water simplifies an athlete's fueling strategy, reducing the need to carry bulky bottles or time consumption around hydration stations.
Versatile Fuelling: The product's success led SiS to develop variations, including options with added caffeine for a mental boost or electrolytes to aid in hydration, expanding its utility for various athletic needs.

Comparison: Isotonic vs. Traditional Gels


Feature	Isotonic Gel (e.g., SiS GO)	Traditional (Hypertonic) Gel	What it means for you
Concentration	Matches body fluids	Higher concentration than body fluids	Smoother digestion, less chance of stomach upset.
Need for Water	Not required for digestion	Required to prevent GI issues	Simplifies fueling strategy; less equipment to carry.
Absorption Speed	Very fast absorption	Slower, requires dilution	Faster energy delivery to working muscles.
Carb Delivery	Approx. 22g per 60ml serving	High carb density in a smaller packet	Isotonic gels are best for frequent, steady carbohydrate intake.
Gastrointestinal Comfort	Low risk of discomfort	High risk of bloating and cramping	Minimizes performance-interrupting stomach problems.
Use Case	Most endurance sports, especially running	Cycling or other sports where water is readily available.

How to Effectively Fuel with Isotonic Gels

For optimal performance, it's crucial to use energy gels correctly. For endurance sessions lasting over 90 minutes, aiming for a carbohydrate intake of 60 to 90 grams per hour is recommended. With a standard isotonic gel providing around 22 grams of carbs, this translates to roughly one gel every 20-30 minutes.

Here’s a simple strategy:

Take the first gel around 15-20 minutes into exercise to top up your glycogen stores.
Continue consuming a gel every 20-30 minutes to maintain steady blood glucose levels and prevent 'hitting the wall'.
If using caffeinated gels, time them for a mental boost later in the race.
Always practice your fueling strategy during training to see what works best for your body.

The Enduring Legacy of the First Isotonic Energy Gel

The creation of the SiS GO Isotonic Energy Gel was a watershed moment that moved sports nutrition beyond simply providing energy. It addressed the critical need for a fuel source that was not only effective but also easy on the digestive system and convenient to use during competition. By removing the barrier of needing to consume water alongside the gel, Science in Sport enabled athletes to focus entirely on their performance. The innovation paved the way for a new generation of sports nutrition, setting a standard that remains relevant and highly valued by athletes across a wide spectrum of endurance sports today.

Explore the science behind energy gels on Science in Sport's website.

Conclusion

The introduction of the world's first isotonic energy gel by Science in Sport forever changed the landscape of endurance fueling. It solved a fundamental problem for athletes by delivering fast, efficient carbohydrates without the risk of gastrointestinal discomfort. This pioneering innovation, backed by solid scientific principles, remains a foundational product in the sports nutrition industry and a testament to how intelligent product design can have a lasting impact on athletic performance.

Frequently Asked Questions

The main difference is the concentration. A traditional, or hypertonic, gel requires you to drink water to aid absorption and prevent stomach upset. An isotonic gel, by contrast, has a similar concentration to your body’s fluids, so it can be absorbed quickly without additional water.

The original SiS GO Isotonic Energy Gel does not contain caffeine. However, Science in Sport offers other versions, such as the SiS GO Energy + Caffeine Gel, which is based on the same isotonic formula but includes caffeine for a mental boost.

Isotonic gels can start delivering energy to your bloodstream within 5 to 15 minutes of consumption. Their rapid absorption is due to the isotonic formula, which allows the gel to move quickly from the stomach to the intestines.

No, the primary advantage of an isotonic energy gel is that it is formulated to be consumed without additional water. This minimizes the risk of bloating and speeds up absorption.

Athletes often choose isotonic gels for their convenience, rapid energy delivery, and ease on the stomach. The no-water-needed formula simplifies fueling mid-race, and the gentle digestion is a major plus for those with sensitive stomachs.

While most beneficial for endurance exercise lasting over 90 minutes, an isotonic gel can be used for shorter, high-intensity workouts. Taking one before a run can provide a quick boost, but consuming them consistently during long activities is where they shine.

Maltodextrin is a type of carbohydrate, typically derived from maize, used in isotonic gels. It provides a fast-acting, easily digestible source of glucose to fuel your muscles during exercise.