Who SiS Is
SiS - short for Science in Sport - was founded in the UK in 1992 with an explicit focus on the endurance audience: cyclists, runners, triathletes. The brand has long-standing relationships with professional cycling teams (including, historically, sponsorships with WorldTour squads) and has built a reputation around lab-led product development.
The Range
SiS's lineup spans GO Hydro tablets (their electrolyte tablet equivalent of Nuun Sport), GO Energy + Electrolyte powder, GO Isotonic Energy Gel (one of the original isotonic gel formats - meaning you don't need to chase it with water), Beta Fuel (higher-carb endurance fuelling), and a broad recovery range.
Formulation Notes
GO Hydro tablets contain ~250 mg sodium per tablet alongside potassium, calcium, and magnesium. The Isotonic Energy gels deliver 22 g of carbohydrate in a format that doesn't require additional water to digest - a key practical detail mid-ride or mid-run. Beta Fuel sits at the upper end of carbohydrate concentration for trained endurance athletes.
Who Reaches For SiS
Australian road and gravel cyclists, triathletes, marathon runners, and ultra-distance hikers. SiS sits firmly in the endurance specialty channel - you'll find it at endurance-specific retailers and the bigger online stores rather than the supermarket aisle.
Best Fit For
- Cyclists, runners, and triathletes following endurance-specialty fuelling
- Long sessions where in-bottle carbohydrate + electrolytes earn their place
- Race-day kit lists with the Isotonic Energy Gel as the standby
Worth Considering Alongside
If you're weighing up SiS - Science in Sport against others in the same use-case bucket, these brand profiles cover the same ground from different angles:
- High5 - Leeds-founded sports nutrition brand with a broad endurance lineup - gels, drinks, energy bars, and recovery products.
- Maurten - Swedish endurance brand built around hydrogel technology, widely used by elite marathoners and cyclists.
- Tailwind Nutrition - Colorado-founded endurance powder that combines carbohydrate and electrolytes in one bottle - popular with ultra and trail runners.
- Precision Fuel & Hydration - UK brand built around personalised sodium and carbohydrate dosing - known for advance sweat testing and tiered electrolyte concentrations.
Frequently Asked
Where can I buy SiS (Science in Sport) in Australia?
SiS is stocked through Australian endurance specialty retailers - cycling and triathlon stores - plus Amazon AU and direct from scienceinsport.com. It's not typically in supermarkets or general pharmacies.
What is an isotonic energy gel?
SiS pioneered the isotonic gel format - a more dilute gel that doesn't need water to chase. The standard concentrated energy gels found in most brands are hypertonic and require water alongside. Our tonicity explainer covers the difference.
Is SiS GO Hydro the same as Nuun?
Both are effervescent electrolyte tablets in the same broad category. Sodium dose, flavour palette, and brand identity differ. SiS leans into the endurance-specialty positioning; Nuun spans endurance plus daily-use variants. Our side-by-side hub sets these out across the brands.
