About Cluster Dextrin (HBCD)
Highly branched cyclic dextrin (HBCD, Cluster Dextrin®, Glico) is a low-osmolality, high-molecular-weight glucose polymer made from amylopectin. Its selling point is fast gastric emptying with less GI discomfort than maltodextrin/dextrose at equal carbohydrate load, supported by gastric-emptying and osmolality data. Performance evidence is thin: a small double-blind crossover in swimmers (Furuyashiki 2014, 15 g) found lower rating of perceived exertion vs maltodextrin with no clear performance or blood-marker difference; Suzuki 2014 (Nutrients) reported blunted post-exercise stress/immune markers vs a glucose drink; a 2025 resistance-training crossover found little ergogenic effect. No trial shows superior endurance or strength outcomes vs cheaper carbohydrates. It is a legitimate exercise fuel — 25–30 g/serving is a meaningful carbohydrate dose — but the 'better than maltodextrin' claim rests on comfort and RPE, not performance. Contains no fibre; caloric (4 kcal/g).
What Cluster Dextrin (HBCD) supports
- Fast-emptying exercise carbohydrate with less GI upset
- Lower perceived exertion vs maltodextrin in one small trial
How much Cluster Dextrin (HBCD) to take
The RDA prevents deficiency. The effective range is what clinical trials used to actually move the outcome.
Effective
15–30
g
Human trials used 15 g (Furuyashiki 2014, endurance RPE) and ~1.5 g/kg (Suzuki 2014, exhaustive exercise cytokines); intra-workout products deliver 25–35 g/serving. As a carbohydrate its benefit scales with total grams; sub-10 g servings are trivial fuel.
Clinical evidence
Limited clinical evidence. Two small crossover trials (2014) show comfort/RPE advantages over maltodextrin or glucose; no performance-outcome superiority demonstrated
NIH Fact Sheet