Also known as: highly branched cyclic dextrin, HBCD, cyclodextrin (sports nutrition)
Cluster Dextrin (HBCD)
·By Croix
What is cluster dextrin (hbcd)?
Highly Branched Cyclic Dextrin (HBCD), marketed in sports nutrition as Cluster Dextrin (a Glico trademark), is amylopectin restructured into a branched cyclic polymer of roughly 16 to 100 glucose units per cluster, with a mean molecular weight around 160,000 Da.
Because the molecule is so large, the osmolality contribution per gram of carbohydrate is extraordinarily low — as low as 9 mOsm per 10 g/100 ml. That means a 12% HBCD drink has roughly the osmotic pressure of a 1.5% dextrose drink, and gastric emptying is dramatically faster than for any other carb source at the same concentration.
How does it work in a sports drink?
The size of the molecule is the entire point. Caloric sensors in the stomach regulate emptying based on energy density per unit volume, not osmolality directly — but osmotic pressure determines how fast the small intestine can absorb the solution once it gets there. HBCD lowers the osmotic load enough that the absorption pipeline doesn't bottleneck, even at concentrations that would shut down a dextrose-based drink.
The trade-off is digestion kinetics. Those long branched cyclic chains take longer for amylase to cleave than maltodextrin's shorter linear chains, so HBCD delivers glucose to the bloodstream as a steadier drip rather than a sharp rise. For 4-hour-plus events at 100+ g/hr that's an advantage. For a 90-minute hard ride or a 60 g/hr training session, plain maltodextrin is doing the same job for ~7× less money.
How do I use it at home?
Reach for HBCD when you're targeting >100 g/hr of carb intake AND running into GI distress on a maltodextrin-based formula. Most riders below that intake rate don't need it.
Pair HBCD with fructose for dual-transporter fueling, same as maltodextrin: roughly 1:0.8 glucose-to-fructose at 100+ g/hr targets.
Bulk HBCD typically costs ~7× the price of maltodextrin per gram. Even so, copying Skratch Super High-Carb or any HBCD-based commercial drink at home is still markedly cheaper than buying the brand.
Dose & usage at a glance
- Typical drink concentration
- 8–12% w/v (HBCD tolerates higher than maltodextrin)
- Osmolality contribution
- ≈9 mOsm per 10 g/100 ml
- When it pays off
- 100+ g/hr fueling targets, multi-hour events
- When maltodextrin is fine
- <90 g/hr training-day fueling
Where to buy it in bulk
We primarily recommend Nutricost-brand products (made in GMP-compliant, FDA-registered facilities, third-party tested), with NOW Foods or BulkSupplements as fallbacks for ingredients Nutricost doesn't stock. The list below shows every channel that carries the product — Nutricost direct, iHerb, and Amazon — sorted by unit price. Pack sizes vary across retailers, so the lowest $/g usually means the largest pack — pick whichever store and size fits your usage. Links are affiliate — the site earns a small commission at no extra cost to you. For ingredients none of the three brands carries (HBCD, table salt, sucrose) we describe the typical specialty- or grocery-store option and skip the affiliate link.
Disclosure: As an Amazon Associate I earn from qualifying purchases.
DIY teardowns that use cluster dextrin (hbcd)
Linked above— all walk through how cluster dextrin (hbcd)fits into the specific commercial product's formulation.