What is Cluster Dextrin®?

Cluster Dextrin® is a next-generation carbohydrate, formally known as a highly branched cyclic dextrin (HBCD). Biochemically, it is derived from waxy corn starch via branching enzyme and cyclisation processing, resulting in a high-molecular-weight glucose polymer with a narrow molecular‐weight distribution. In simpler terms: it’s a high-quality, engineered carbohydrate that differs structurally from traditional maltodextrin or glucose powders. Its brand name “Cluster Dextrin®” is often used in sports-nutrition formulations to signal premium carb fuel.

How Does It Work in the Body?

Gastric emptying & absorption

One of the key performance features of Cluster Dextrin® is faster gastric emptying and smoother stomach transit than other carbs forms. Because of its molecular structure, HBCD results in a solution with lower osmotic pressure compared to many simple carbs. Lower osmotic pressure means the fluid leaves the stomach faster and enters the small intestine more rapidly. A classic human trial showed that ingestion of HBCD prolonged time-to-exhaustion by 70% compared to glucose in elite swimmers - part of the mechanism being better maintenance of blood glucose and less GI distress.

Sustained energy delivery

Because HBCD is less likely to cause rapid insulin spikes or dramatic blood-glucose swings than some highly-simple sucrose or dextrose formulations, it tends to provide a steadier stream of fuel. Some research suggests a reduction in Rating of Perceived Exertion (RPE) and improved endurance when using HBCD vs conventional carbs.

Gut comfort and hydration compatibility

Because of its favourable gastric behaviour (faster emptying, less “stomach full” feeling, lower incidence of belching or GI upset), Cluster Dextrin® is often described as more gut-friendly in high-volume or heat/humidity conditions. This is especially relevant for endurance athletes who must consume large volumes of fluid + carbs during long sessions, while avoiding GI issues.

How Does It Differ from Other Carbohydrates?

vs. Glucose / Dextrose

Glucose (also called dextrose) is a simple sugar that’s rapidly absorbed but can lead to quick spikes and falls in blood sugar, and the osmotic load of a high-sugar drink may slow gastric emptying. Cluster Dextrin® provides a slower, steadier energy release and better gut handling. In research, swimmers fed HBCD lasted longer than those fed equivalent glucose.

vs. Maltodextrin

Maltodextrin is a common carbohydrate polymer derived from starch, used widely in sports drinks, including our other regular drink mixes. It’s more complex than glucose but often still has a broad molecular-weight distribution and can result in higher osmolarity when concentrated. In contrast, HBCD is engineered to a narrower molecular‐weight range (400,000 Da in one trial) and lower osmolality, helping faster emptying. 

Practical implications

For the athlete:

• Traditional carb drinks might cause gut fullness or delayed absorption when consumed at high volumes or in hot/humid conditions.
• Cluster Dextrin®-based formulas allow higher carb intake (e.g., 60 g+ per serving) with less GI risk, making them ideal for long sessions, races or training in heat.
• Because of smoother digestion, you may tolerate a higher carbohydrate per hour target with HBCD compared to standard carbs.

 

Research Evidence & What It Tells Us

Here are some key findings from published studies:

• In one study of elite swimmers, ingestion of HBCD (versus glucose or water) resulted in a 70% longer time to exhaustion during a high-intensity swim protocol.
• A review article concluded that HBCD “may provide increased performance or endurance compared to other carbohydrate sources such as maltodextrin and glucose” especially in whole-body endurance exercise
• Studies also found reduced gastrointestinal symptoms (e.g., belching, flatulence) with HBCD compared to equivalent carb solutions.

Bottom line: While no magic bullet, HBCD presents a meaningful upgrade for endurance fuel formulations, with good science to back improved gut comfort and steady fuel delivery.

When & How to Use It in Endurance Settings

Ideal for long sessions and hot/humid conditions

Endurance athletes often struggle to consume enough carbohydrates when training or racing in heat/humidity due to gut-stress, slower digestion and fluid loss. A HBCD-based drink formula helps by reducing gastric bottlenecks and allowing higher carb loads with less discomfort.

Carbohydrate target

Typical guidelines for endurance performance suggest 30-60 g carbs per hour, and advanced athletes may target 90 g or more. A HBCD-formula that can deliver 60 g carbs per serving (or more) with smooth digestion is well-suited for those higher targets.

Mix & ingestion tips

• Ensure you mix at the correct concentration recommended by the product (e.g., 60 g carbs plus electrolytes per 750 mL water).
• Sip steadily throughout the session, aiming to hit your target carb/hour.
• Because HBCD is gut-friendly, you may tolerate more frequent or higher volume ingestion compared to standard carbs but still train your gut.

Practical scenario

When racing in tropical conditions or on a long bike ride of 3-5 hours, the athlete may choose a HBCD-based drink, consume one serving per hour (60 g carbs) plus electrolytes, and if tolerated consider increasing to 90-120 g carbs/hour by adding gels or second serving. The smoother digestion means less risk of gut distress late in the race.

Limitations & Considerations

• Cost: HBCD tends to be more expensive to source/manufacture compared to generic maltodextrin or glucose powders.
• Product formulation still matters: HBCD alone isn’t enough - you still need electrolytes, hydration strategy and gut-training.
• Carbohydrate dose still applies: HBCD does not replace the need to hit your carbohydrate per hour target - it's a tool to better tolerate high doses, not a free pass to neglect consumption.

Why It Matters for Active Vita Endurance Fuel

At Active Vita we design formulas for serious endurance athletes training/racing in heat, humidity, and long durations. Using Cluster Dextrin® in our Pro Fuel drink mix aligns perfectly with those needs because:

• It supports higher carbohydrate loads with less gut stress - ideal when you’re pushing for 60-120 g carbs/hr.
• The smooth digestion and low GI sensation align with late-race comfort and performance.
• In heat/humidity, when gastric emptying often slows, a low-osmotic, fast-emptying carb like HBCD is a smart choice.
• When combined with high sodium, buffering agents and practical mixing guidelines, HBCD helps deliver not just carbs but complete endurance fuel - sustaining energy and hydration while minimising GI issues.

Summary & Practical Key-Takeaways

• Cluster Dextrin® (HBCD) is a high-molecular-weight, engineered carbohydrate with a narrow molecular-weight distribution, low osmotic pressure, fast gastric emptying and solid evidence of performance benefit.
• It stands out from glucose, dextrose and standard maltodextrin by offering smoother digestion, reduced gut distress and better suitability for high-volume fuelling.
• For endurance athletes, the big benefit is tolerating higher carb loads (60 g/hour and beyond) in challenging conditions (heat, humidity, long races) with less stomach upset.
• It’s not a silver bullet - training your gut, managing hydration and electrolytes, and hitting your carb numbers still all matter.
• It is costlier and research is still developing, but for serious athletes and long-duration events it can offer a meaningful edge.