A personal note on performance carbs
For years, I believed all carbohydrates were created equal, simple energy in, simple energy out. If I had a tough session coming up, I’d reach for the usual suspects: glucose, dextrose, maybe some maltodextrin. It worked, but just barely. Energy crashes mid-session, GI distress, and that all-too-familiar “heavy gut” feeling were constant side effects I learned to live with.
That changed the day I discovered Highly Branched Cyclic Dextrin (HBCD), also known as Cluster Dextrin. I first encountered it buried in the ingredients list of a premium intra-workout formula. No spike, no crash. Just smooth, sustained performance. I began digging into the science, and what I found completely rewired my understanding of carbohydrate timing, digestion, and delivery.
Let’s unpack what makes HBCD a standout performance fuel, and why research suggests it might be the ultimate carbohydrate for athletes chasing intensity and endurance.
What is HBCD?
Highly Branched Cyclic Dextrin (HBCD) is a cutting-edge carbohydrate derived from waxy corn starch through enzymatic treatment with branching enzymes. The result is a molecule with a cyclic, highly branched structure giving it a high molecular weight (~400,000 Da) and low osmotic pressure, two features that make it vastly different from standard carb sources like glucose or even traditional maltodextrin.
In simpler terms, HBCD is a designer carb built for performance: it’s stable in water, highly soluble, tastes neutral, and most importantly, digests rapidly without the stomach upset.
Its structure enables it to pass quickly through the stomach (gastric emptying) and deliver energy to working muscles more efficiently than lower-weight sugars, while avoiding insulin spikes and GI distress.
What are the benefits of HBCD?
HBCD’s benefits stem from how its unique structure affects absorption, metabolism, and energy delivery. Here's what sets it apart:
Faster gastric emptying: Thanks to its low osmolality, HBCD clears the stomach quickly, faster than glucose and standard maltodextrin. This means quicker delivery of carbs to the bloodstream without bloating or stomach cramps.
Stable blood glucose: Ingesting HBCD leads to a sustained release of glucose into the blood without sharp spikes or crashes, ideal for endurance training or long, glycogen-depleting sessions.
Reduced perceived exertion: Athletes report lower Ratings of Perceived Exertion (RPE) during workouts after ingesting HBCD, suggesting better fuel availability and reduced fatigue.
No GI distress: Unlike fructose-heavy or concentrated glucose drinks, HBCD has been shown to cause minimal gastrointestinal discomfort, even at higher doses.
Greater endurance: Studies in both mice and humans show HBCD significantly improves time to exhaustion, meaning athletes can push harder, for longer.
What does the research say?
A 2015 study published in Food Science and Technology Research evaluated the effects of HBCD on endurance performance in elite swimmers. Seven national-level Japanese swimmers performed repeated swimming trials under three conditions: HBCD intake, glucose intake, or plain water (control).
Here’s what the researchers found:
Time to exhaustion increased by ~70% in the HBCD group compared to both glucose and water. Swimmers lasted 504.4 ± 133.3 seconds vs. ~300 seconds in the other groups.
Blood glucose was consistently higher in the HBCD group throughout the test, even outperforming the glucose condition in later exercise stages, indicating more stable and sustained energy delivery.
Lactate levels were also higher post-exercise, suggesting more efficient carbohydrate oxidation and better energy turnover with HBCD.
Why was this so significant?
Because despite both HBCD and glucose elevating blood glucose, glucose may trigger higher insulin, potentially leading to hypoglycemia and reduced fat oxidation, a common problem in endurance athletes. HBCD, on the other hand, seems to offer the glucose stability without the insulin penalty, allowing for better metabolic balance during intense training.
Furthermore, because of HBCD’s lower osmotic pressure, gastric emptying is less inhibited, even at high training intensities (>75% VO₂max). This translates to faster absorption of fluids and nutrients, and a reduced risk of stomach upset.
How to take it
HBCD is best used before or during training, particularly when the session is long (over 60 minutes), intense (glycolytic), or performed fasted.
Suggested dosing:
1.0–1.5 g per kg body weight as used in the referenced study
Roughly 20–40g for most athletes pre- or intra-workout
Mix with 300–600 mL of water depending on taste preference and fluid needs
Best forms to take it in
HBCD is widely available as a standalone unflavored powder or as part of premium intra-workout blends combined with amino acids, electrolytes, or creatine.
If opting for a single-ingredient form:
Look for “Cluster Dextrin®” the patented version of HBCD produced in Japan
Choose unflavored if stacking with other performance supplements
Ensure no added simple sugars are blended into the mix (read the label)
Top-tier intra-workout blends often pair HBCD with:
Essential amino acids (EAAs) or BCAAs
Creatine monohydrate
Betaine or taurine for hydration support
Electrolytes for endurance training in hot climates
Conclusion: When performance matters, carbs matter more
Not all carbohydrates are created equal, and HBCD is proof.
From elite swimmers to serious lifters, the research is clear: HBCD improves performance, delays fatigue, stabilizes energy, and keeps your stomach happy, even under the stress of high-intensity training.
In a world full of sugar-laden sports drinks and misleading marketing, HBCD stands out for one reason: it’s engineered to work.
If you're training hard, chasing endurance, or trying to stay sharp through demanding workouts, consider swapping your usual carb source for Highly Branched Cyclic Dextrin. Whether you’re prepping for a triathlon, grinding through a two-hour lifting session, or just looking for clean fuel that won’t fail you halfway through, HBCD deserves a place in your performance stack.
Reference: TY - JOUR AU - Shiraki, Takahisa AU - Kometani, Takashi AU - Yoshitani, Kayo AU - Takata, Hiroki AU - Nomura, Takeo PY - 2015/05/01 SP - 499 EP - 502 T1 - Evaluation of Exercise Performance with the Intake of Highly Branched Cyclic Dextrin in Athletes VL - 21 DO - 10.3136/fstr.21.499 JO - Food Science and Technology Research ER -
