CoreCtrl is an electrolyte powder mixed with water, with L-taurine as its key ingredient. Research has examined whether the naturally occurring compound can help the body begin sweating at a lower temperature, supporting heat loss during intense exercise.
Brownlee said the product grew from scientific work by Jennifer Peel, whose research found that taking around 50 milligrams per kilogram of body weight for eight days improved exercise performance in hot conditions.
The former Olympic triathlon champion has also tested CoreCtrl himself, saying he noticed he “started sweating sooner”. For footballers, that earlier response could matter during long spells of pressing, recovery runs and set-piece defending in difficult conditions.
England’s players have also been using cooling vests and palm-cooling devices during training in Kansas City. The immediate test against the Democratic Republic of the Congo will be staged indoors at Atlanta’s Mercedes-Benz Stadium, limiting the direct impact of extreme heat.
The wider preparation is aimed at what could follow. England’s first two matches came in mild, wet weather in Boston and New York, but a last-16 tie in Mexico City would introduce altitude, while a potential quarter-final in Miami could bring intense heat and humidity.
That makes the drink just one part of a broader strategy. Hydration, cooling, recovery and sensible pacing will all become increasingly important as the tournament advances. The FA’s agreement with Lucozade remains in place, but the specialist product underlines how narrowly tailored elite tournament preparation has become.
England’s next challenge is therefore about more than overcoming the Democratic Republic of the Congo. If they progress, the real test will be whether Tuchel’s squad can carry this carefully designed heat plan into Mexico City and beyond.