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DIY endurance fueling ingredient

Maltodextrin (DE 10-15)

Maltodextrin is a partly broken-down starch — a glucose polymer that adds carbs to a bottle without proportionally raising its osmolarity, which is why almost every commercial sports drink uses it.

What it is, and how to use it

Maltodextrin is not a single molecule but a family of glucose chains, typically 3–20 units long, produced by enzymatic breakdown of corn or rice starch. The body cuts the chains back into free glucose in the gut and absorbs it through the SGLT1 transporter just like any other glucose source.

The reason it dominates sports nutrition is osmotic load. A gram of sucrose contributes around 2.92 mOsm to a litre of water; a gram of low-DE maltodextrin contributes about 0.5 mOsm because each molecule carries many glucose units. That means you can pack 15–18% w/v carbs into a bottle and stay close to isotonic — a glucose-only drink at the same strength would be uncomfortably hypertonic.

In a DIY mix, pair maltodextrin with fructose (or sucrose) to recruit both SGLT1 and GLUT5 transporters and unlock the >60 g/h ceiling that glucose alone hits. A typical pairing is 1:0.8 maltodextrin:fructose at high carb-rate efforts (>90 g/h). DE 10–15 grade is the standard for endurance use; higher DE tastes a bit sweeter and has higher osmolarity. German bulk price is €3–5/kg from sports-nutrition suppliers (Decathlon, fitstore, Amazon DE). Stores well; absorbs moisture, so keep the bag sealed.

Composition

Total carbs
100 % by weight
Glucose
100 % of carb mass
Fructose
0 % of carb mass
Other carbs
0 % of carb mass
Sweetness factor
0.05 × sucrose
Osmolarity
0.50 mOsm / g carb

Typical values; expect ±5% variance between producers / lots.

Try this ingredient in the DIY endurance fueling calculator.

Sources & citations

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