Carbohydrate Gels

Maltodextrin is a glucose polymer — chains of glucose units linked together. In the gut, it hydrolyses rapidly to free glucose, which is absorbed via the SGLT-1 sodium-glucose co-transporter. DE 10-15 (dextrose equivalence of 10-15) gives a relatively neutral flavour profile and manageable viscosity compared to lower-DE starches. It provides the majority of carbohydrate energy in the gel and forms the backbone of the fueling strategy.

Crystalline fructose activates the GLUT-5 intestinal transporter — an entirely separate absorption pathway to glucose. Once SGLT-1 is saturated at ~60 g/h glucose equivalent, only fructose can increase total carbohydrate absorption. At 13.3 g alongside 16.7 g maltodextrin, the glucose-to-fructose ratio is approximately 1:0.8. This ratio has the strongest meta-analytic support for maximising oxidation rates approaching 120 g/h in trained athletes.

Contributes approximately 100 mg sodium per serving. Sodium citrate is the milder-tasting sodium source: at these concentrations, sodium chloride alone can leave a sharp, salty taste. Citrate also acts as a mild alkalising buffer, partially counteracting the acid load from citric acid and helping to stabilise the flavour profile of the final gel. Combined with sodium chloride, it achieves ~200 mg total sodium — within the 150–250 mg/serving target range.

Table salt. Contributes ~100 mg sodium and the chloride anion lost in sweat alongside sodium. The body loses approximately 20–80 mmol/L sodium in sweat depending on individual variation and acclimatisation status. A 200 mg sodium dose per gel replaces a meaningful fraction of sweat losses when gels are taken at 2–3/hour, without over-supplementing athletes with lower sweat rates.

Contributes ~50 mg potassium. Potassium is the primary intracellular electrolyte and is lost in sweat at approximately 150–500 mg/L. Acute potassium depletion sufficient to cause cramping or performance loss during single-session exercise is unlikely in healthy athletes, but inclusion at low doses aligns with multi-electrolyte replacement philosophy and adds negligible cost or complexity.

Drops the pH of the finished gel to approximately 3.8–4.2 — below the 4.6 threshold for acidified food classification. At this pH, most spoilage organisms and pathogens cannot grow, significantly extending shelf stability without refrigeration. Citric acid also contributes tartness that balances the sweetness of fructose and maltodextrin, improving palatability and reducing the perception of cloying sweetness during intense exercise.

At 0.08 g per 40 g serving (0.2% w/w), xanthan gum creates the characteristic viscous, spoonable-to-pumpable gel texture. It is a GRAS (Generally Recognised as Safe) polysaccharide produced by fermentation. Critically, xanthan provides pseudoplastic behaviour: it thins under shear (when squeezed from a sachet), making the gel easy to consume, while thickening at rest, preventing the gel from being too watery. Temperature affects viscosity — the gel becomes thinner above 25°C.

A GRAS preservative effective against yeast and mould at ≤0.1% use level. Its activity is pH-dependent: below pH 4.6, the undissociated sorbic acid form predominates, which is the antimicrobially active species. This is why citric acid and potassium sorbate work synergistically in this formula. Without the acidic environment, sorbate at this dose would be largely ineffective. Note: homemade batches should be consumed within 2–4 weeks without validated commercial shelf-life testing.