Know what to take.
Down to the minute.
Get your personalised fuelling plan.
If you have tested your sweat rate or sodium concentration, entering these will sharpen the fluid and electrolyte recommendations. Leave blank to use the algorithm's estimates.
Algorithm informed by published research on exercise fluid replacement, sweat rate, sweat sodium concentration and carbohydrate use during endurance exercise, including Sawka et al. (2007), Jeukendrup (2011) and Baker (2017). Constants: 40 g carbohydrate per gel, 1 g salt per high-salt gel, 0.25 g salt per low-salt gel and 1 g salt per electrolyte serving. Scientific estimate only. Individual variation exists. Validate all recommendations in training before race day.
From the founder
truefuels exists to help you be your best. It was built on a simple idea: stop fuelling being the thing that lets you down. I set out to simplify the process and simplify the products — to build a fuelling solution you could rely upon whatever the event. Energy gels fuel the work. Electrolytes keep the fluid environment right so that work is possible. CoreCtrl supports the cooling system that keeps you in control when the heat is on.
This calculator helps you put the right products together, in the right amounts, at the right time. It's not going to be perfect 100% of the time, but use it as a good guide — I built the logic on the latest scientific literature and my own experience. And always test your nutrition in training.
— Alistair Brownlee, co-founder, truefuels
Races aren't lost at the finish. They're lost at mile 18.
60–90%
of endurance athletes are chronically underfuelled on race day.
2%
dehydration is all it takes to wreck performance
2°C
is all the core temp rise needed to start slowing you down
Three Problems. One System.
Built by Alistair Brownlee from real race experience. Each product solves one problem. All three stack together.
Hitting the Wall
Glycogen stores deplete in under two hours at race intensity. When blood glucose crashes, both physical output and cognitive function collapse.
Energy Gels
Cramping
Sweat removes 2.4–3.6g of salt per hour at race intensity. A sodium deficit disrupts neuromuscular signalling and fluid balance.
Electrolytes
Overheating
As core temperature rises, the body diverts blood from muscles to skin. Heart rate climbs and the brain progressively shuts down motor output.
CoreCtrl
