Also known as: Maltodextrin, Highly branched cyclic dextrin, HBCD, Cluster Dextrin, Dextrose equivalent
EnduranceStrong evidence
Carbohydrate powders used to fuel long sessions and refill glycogen. The difference between the cheap and expensive options comes down to osmolality, which determines how fast your stomach empties.
Typical dose
30.0–90.0 g per day
During sessions over 90 minutes; and post-training for glycogen refill
What it is
Both are glucose polymers — chains of glucose molecules produced by breaking down starch, usually from maize, tapioca or waxy barley. Neither is a sugar in the everyday sense, though maltodextrin raises blood glucose as fast as or faster than table sugar.
Maltodextrin is characterised by its dextrose equivalent, a measure of how thoroughly the starch has been broken down. Lower DE means longer chains, lower osmolality and gentler on the stomach; higher DE means shorter chains and faster absorption but more osmotic load.
Highly branched cyclic dextrin is a specifically engineered molecule with a large, uniform structure. Its selling point is very low osmolality despite high molecular weight, which is a genuine physical property rather than a marketing claim — the question is whether it justifies the price gap.
How it works
Osmolality is the key concept. A solution with high osmolality draws water into the stomach and slows gastric emptying, which is the main cause of the sloshing, bloated feeling during long sessions.
Cyclic dextrin achieves low osmolality because its molecules are large and uniform, so a given weight of carbohydrate contributes fewer dissolved particles. That means it clears the stomach faster than an equivalent concentration of maltodextrin.
Absorption is then limited by intestinal transporters. Glucose absorption saturates at around 60 g per hour, which is why endurance protocols combine glucose with fructose — fructose uses a different transporter, and the combination pushes total absorption to 90 g per hour or more.
What the evidence shows
Carbohydrate fuelling during prolonged exercise is one of the most firmly established practices in sports nutrition. Intake during sessions over about 90 minutes reliably improves performance, and the dose-response relationship is well characterised.
The glucose plus fructose finding is robust and practically important, allowing higher fuelling rates without the digestive problems that come from pushing glucose alone past its transporter limit.
Cyclic dextrin's specific advantage over maltodextrin is less firmly established than the price difference implies. Gastric emptying differences are demonstrable, but trials showing superior performance outcomes are fewer and smaller. If you tolerate maltodextrin, the case for paying several times more is weak.
Dosing
For sessions of 1 to 2 hours, 30 to 60 g per hour is appropriate. Beyond 2.5 hours, up to 90 g per hour is achievable but only with a glucose and fructose combination, typically at a 2:1 ratio.
Pure maltodextrin or cyclic dextrin will hit the 60 g per hour ceiling, since both are glucose-based. Adding fructose is what unlocks the higher rates, not switching to a more expensive dextrin.
Gut tolerance is trainable. Practising high-carbohydrate fuelling in training genuinely improves how much you can absorb, and this matters more than which powder you buy. Mix to around 6 to 8 per cent concentration for during-exercise use; stronger solutions slow emptying regardless of source.
At a glance
Common forms
Maltodextrin (various DE), Highly branched cyclic dextrin, Cluster Dextrin, Glucose and fructose blends, Within energy drinks and gels
Half-life / duration
Absorbed within 30-60 minutes; glycogen refill occurs over hours
Timing
During sessions over 90 minutes; and post-training for glycogen refill
Competition status
Permitted — not on the WADA Prohibited List
Category
Endurance
Safety and side effects
Both are foods and are safe. The practical issue is digestive: bloating, cramping and diarrhoea when concentration or intake rate exceeds what your gut can handle.
Getting the concentration right matters more than most people realise. A drink mixed too strong will sit in the stomach and cause problems regardless of which carbohydrate source it uses.
Maltodextrin raises blood glucose sharply, so take care if yours is being managed. Speak to your doctor before using it regularly if that applies to you.
Who should avoid it
Take care if your blood sugar is being managed — maltodextrin raises blood glucose sharply. Build up fuelling rates in training rather than trialling them on race day. Some maltodextrin is derived from wheat; check allergen declaration if you avoid gluten.
This entry is provided for information only. Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Consult a qualified healthcare professional before use if you are pregnant, breastfeeding, taking medication or under medical supervision.
