Science in Sport (SiS): Range, Bestsellers & Who It's For

If you run, cycle, swim or train for endurance events and you're weighing up Science in Sport (SiS) products, this guide explains what the brand makes, who it suits and how to choose within the range.

What is Science in Sport (SiS)?

Science in Sport is a British sports-nutrition brand founded in 1992. It built its reputation in endurance sport — cycling, running and triathlon, where energy and hydration over long durations matter most. SiS is widely credited as a pioneer of the isotonic energy gel, the format the brand is still best known for. A defining feature of the range is that products are certified under the Informed Sport programme, meaning batches are independently tested for substances banned in competition — a genuine consideration for anyone who competes under anti-doping rules.

Who is SiS for?

SiS is aimed primarily at endurance athletes and anyone training for distance. You'll get the most from the range if you:

• ride, run or swim for an hour or more and need fuel you can take on the move
• follow a training plan for a marathon, sportive, triathlon or similar event
• compete in tested sport and want batch-tested, Informed Sport-certified products
• want a recovery option to use after long or intense sessions

If your main goal is building size in the gym rather than endurance performance, a dedicated protein powder range may suit you better — though SiS still offers protein and recovery products worth a look.

What's in the SiS range?

SiS organises its products around the demands of a training session or race: fuelling before and during, then recovering afterwards. Here are the main categories you'll find in the Science in Sport collection at NE Commerce.

Energy gels and carbohydrates

The GO Isotonic Energy Gel is the product SiS is best known for — an isotonic gel designed to be taken without water, so it's easy to use mid-effort. Each gel supplies around 22g of carbohydrate. For longer, harder efforts, the Beta Fuel range steps things up, with gels delivering roughly 40g of carbohydrate in a 1:0.8 maltodextrin-to-fructose ratio to help athletes work towards the higher hourly carbohydrate intakes used in endurance fuelling. Carbohydrate is the body's main fuel for sustained, higher-intensity exercise, which is why a fuelling strategy matters on long days out. Browse energy and carb options in our carbohydrates collection.

Hydration and electrolytes

For sessions where you're sweating heavily, SiS offers electrolyte options. GO Hydro is a calorie-free effervescent tablet that dissolves in water to provide electrolytes including sodium, useful when you want hydration without added carbohydrate. GO Electrolyte combines carbohydrate with electrolytes in a drink powder, so you fuel and hydrate at the same time. Carbohydrate-electrolyte solutions can help maintain endurance performance during prolonged exercise and support water absorption during physical activity. See more in the hydration and electrolytes collection.

Recovery and protein

After a hard session, REGO Rapid Recovery is SiS's best-known recovery drink, combining carbohydrate, protein and electrolytes in a single mix to use post-exercise. Protein contributes to the growth and maintenance of muscle mass, which is why a protein-containing recovery product is a common part of an endurance routine. SiS also produces protein powders and bars for everyday intake, which you can compare alongside other brands in our protein range.

Bars, powders and everyday options

Beyond gels and drinks, SiS makes energy and protein bars, oat-based bakes and powders in a range of flavours, giving you real-food-style options for training days, travel or an easy snack between sessions.

How to choose within the SiS range

Start with the length and intensity of your typical session:

• Short to moderate efforts (up to ~90 minutes): GO Isotonic gels plus GO Hydro for hydration are a simple, proven combination.
• Long or racing efforts (90 minutes plus): the Beta Fuel range is built for higher carbohydrate intakes, so it suits marathons, long rides and triathlons.
• Hot conditions or heavy sweating: prioritise electrolytes — GO Hydro if you want zero calories, GO Electrolyte if you want fuel and fluids together.
• After training: REGO Rapid Recovery or a SiS protein product to support your recovery routine.

A few practical pointers: try any new gel or drink in training before you rely on it in a race, so you know how your stomach responds; check flavours, since SiS offers several and preference matters over long durations; and if you compete in tested sport, the Informed Sport certification across the range is a real advantage. For a deeper look at post-session nutrition, our guide to the science of muscle recovery is a useful companion read.

The bottom line

Science in Sport is a British, endurance-focused brand whose strengths are simple, effective fuelling and hydration, plus the reassurance of Informed Sport certification across the range. Whether you need a gel for your next long run, electrolytes for hot days or a recovery drink after hard training, there's a clear place to start. Browse the full Science in Sport range at NE Commerce to see current stock, flavours and prices, with fast tracked UK delivery Monday to Friday.

A quick note

This article is general information, not medical or nutritional advice. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle, and should not be used to prevent or treat any illness. Always read the product label, do your own research, and speak to a qualified doctor, pharmacist or registered nutritionist before starting a new supplement — especially if you are pregnant, breastfeeding, under 18, taking medication or managing a health condition.