2:1 Glucose:Fructose Ratio – why it's an essential standard for endurance

Unlike a 100% glucose or maltodextrin-only intake, the 2:1 ratio allows the body to use two different intestinal transporters (SGLT1 for glucose, GLUT5 for fructose), which increases the maximum carbohydrate absorption capacity per hour.

Proven benefits:

1. Maximum absorption
   With 100% glucose, the ceiling is ~60 g/h (SGLT1 limit).
   With 2:1, it easily goes up to 90 g/h and even 120 g/h in gut-trained athletes – without transporter saturation.
2. Higher energy and delayed bonk
   More absorbed carbohydrates = more exogenous oxidation during exercise → less reliance on muscle glycogen → fatigue delayed by 10–30% in efforts >2 h.
3. Better digestive tolerance at high doses
   Meta-analyses (Stellingwerff 2014, Pfeiffer 2019) show that the 2:1 ratio significantly reduces gastrointestinal symptoms (nausea, cramps) compared to 100% glucose when exceeding 60–70 g/h.

In Elixyr, we strictly apply this 2:1 ratio because it is the dose that allows amateur athletes to aim for 90 g/h (and more) without compromise.