24/7 Customer Support
Free returns
Same-day & Next-day Delivery
Quality Guaranteed
Download the APP
Categories
As an endurance athlete, you know the feeling. One moment you’re hitting your stride, the next you’re facing the dreaded wall. Maintaining energy levels is the key to unlocking your performance potential, whether you're tackling a local 10k, a challenging sportive or a full marathon. With so many options available, choosing the right fuel can feel overwhelming.
This guide is designed to help you navigate the world of Science in Sport energy gels. We'll break down the different types available, explain which one might be right for your specific needs and offer some practical advice to help you fuel your next personal best.
Selecting the correct endurance sports nutrition isn't just about grabbing any gel off the shelf. Your choice should be a calculated part of your training and race-day strategy. Here are a couple of key factors to consider.
The science behind energy gels has evolved, leading to specialised formulas for different types of exertion.
Isotonic Energy Gels: An isotonic energy gel is formulated to have the same concentration of particles as your body's fluids. This means it can be absorbed very quickly into your bloodstream, delivering energy fast without needing to be taken with extra water. This makes them an excellent choice for runners who want to travel light or for any athlete needing a rapid energy boost without the risk of feeling bloated. The original SiS GO gel is a prime example of an energy gel no water is needed for.
High Carb Energy Gels: For longer events like marathons or multi-hour cycle rides, your body needs a much larger and more sustained supply of carbohydrates. A high carb energy gel is designed for this purpose. Many advanced formulas, such as SiS Beta Fuel, use a dual source carbohydrate system, typically combining maltodextrin and fructose. This allows your body to utilise two different transport pathways to absorb more carbohydrates per hour (often 80-120g) than it could with a single-source formula, helping to sustain peak performance over several hours.
The length and intensity of your activity are the most important factors in your fuelling plan.
For sessions under 90 minutes: A single isotonic energy gel taken part-way through can provide the boost you need to finish strong. They are perfect as convenient running gels or for a quick hit of energy during an intense circuit.
For sessions over 2 hours: This is where a structured fuelling strategy becomes critical. A high carb energy gel designed for sustained performance is more suitable. By planning to take a gel at regular intervals, you can consistently replenish your glycogen stores, delay fatigue and maintain your pace from start to finish. These are the go-to marathon gels and cycling fuel for serious competitors.
Based on their formulation and intended use, here are two standout options from the Science in Sport range that cater to different athletic needs.
Why It Stands Out This is the product that introduced the concept of an isotonic gel to the world. Its primary advantage is its convenience and rapid action. The formula is designed to be light on the stomach and deliver energy quickly, which is exactly what you need when the intensity is high. The variety pack is a practical way to try multiple flavours and find what works for you on race day.
Pros
Who is it for? This gel is suitable for athletes looking for a fast and convenient energy source during training or events lasting up to 90 minutes. It's particularly popular with runners and those participating in high-intensity sports where carrying extra fluid is impractical.
View the SiS GO Isotonic Gel Variety Pack on Joybuy.co.uk
Why It Stands Out The SiS Beta Fuel gel is engineered for serious endurance. Its key feature is the high-carbohydrate content delivered via a dual source carbohydrate ratio of 1:0.8 maltodextrin to fructose. According to Science in Sport, this ratio is optimised to increase the amount of carbohydrate your body can process per hour, while minimising the risk of gastrointestinal distress that can occur with high-volume fuelling.
Pros
Who is it for? This is the choice for dedicated endurance athletes. If you're a marathon runner, triathlete or long-distance cyclist aiming to consume 80-120g of carbohydrate per hour to maintain peak performance, the Beta Fuel gel is built for your needs.
Explore the SiS Beta Fuel Gel on Joybuy.co.uk
Every athlete's fuelling strategy is personal. If these gels aren't quite what you're looking for, or if you want to explore energy chews, bars and hydration powders, there are many other solutions available.
To find the perfect match for your training regimen, browse our complete collection of Sports Nutrition & Performance products.
How often should you take Science in Sport energy gels? This depends on the product and your activity. For SiS GO Isotonic gels, a common strategy is to consume 1-3 gels per hour to achieve a target intake of 60-90g of carbohydrate. For the high-octane SiS Beta Fuel, you can consume 1-3 gels per hour to reach the higher target of 80-120g of carbohydrate, which is recommended for events lasting over two hours. Always refer to the product's specific guidance.
Do you need to drink water with SiS GO Isotonic gels? No. The SiS GO gel is an isotonic energy gel, which means it is formulated to be absorbed quickly without additional water. This is one of its main benefits. However, it's important to remember that using gels does not replace your separate hydration strategy—staying hydrated is still crucial for overall performance.
What is the main difference between SiS GO and SiS Beta Fuel? The primary difference lies in their carbohydrate content and formulation. The SiS GO Isotonic gel provides 22g of carbohydrate for rapid, easily digestible energy. In contrast, SiS Beta Fuel is a high carb energy gel delivering 40g of dual source carbohydrate in a specific 1:0.8 ratio, designed to maximise fuel absorption during prolonged, high-intensity endurance events.