How CCD goes from gooey starch to ultimate fuel source.

Cyclic Cluster Dextrin (CCD) is EFS-PRO’s main fuel source. As always for First Endurance ingredients, the reasoning for why is rooted in research-driven benefits. It digests faster, it’s easier on overworked GI tracts, and it helps your body absorb other critical performance nutrients like electrolytes and BCAAs.

We’ll break down the research on those benefits in the next CCD blog. For this one, Dr. Bucci takes us on a tour of what, exactly, CCD is, and why it’s so powerful for endurance athletics.


CCD Performance Benefits

  • Delivers more glucose in a form that is soluble.
  • Empties from the stomach quickly.
  • Breaks down quickly to release glucose.

Cyclic Cluster Dextrin (CCD) is the common term for a trademark name (CCD®) for Highly-Branched Cluster Dextrins (HBCDs) from a Japanese company called Ezaki Glico. CCDs are not cyclodextrins, and not “regular” single-chain starches like amylose or maltodextrins, but they more closely resemble amylopectins (branched-chain starches). With a twist – literally. 

 Glico patented a method of making CCD by fermentation of starch using heat and bacterial branching enzymes (Takaha 2017). Controlling temperature enables small chunks of branched starch chunks to be made.

CCD is so significant because it solves one critical problem. Normally, those starches have a reducing (open sugar) end on each chunk, which causes real-world problems such as being a mess to manipulate. It turns to a thick goo and is not easy for enzymes to digest – not helpful and actually less of a glucose source for us.

 The patented method that gives us HBCDs ends up with small chunks of branched starch (very much like small glycogen) that do not have that self-defeating reducing end. Under specific conditions, the branching enzyme attaches that reducing end on each chunk onto itself, making a 3-D spiral-shaped tube.


You may have read “very much like small glycogen” and asked: Why not just use glycogen itself in EFS-PRO? After all, it’s how our bodies replenish blood glucose and keep exercising, so why not put it in a pill, powder, or drink?

 You do not see glycogen itself used in food and supplements because it also suffers from those reducing ends, so it’s a huge slimeball of branched chain glucose strings. Livers love it, but human guts do not have the best mix of starch-digesting enzymes to break it down as fast as liver cells can, so glycogen has delayed gastric emptying – not a good thing during exercise, and not an efficient source of glucose when consumed in hydration mix.

 So yes, CCDs closely resemble glycogen if glycogen were built for processing through the GI tract instead of in livers and muscles – think of CCDs as an oral, extra source of predigested glycogen.

Figure 1: Two-dimensional image of a typical highly-branched cyclic dextrin as found in CCD® (adapted from Choi et al., 2009).


Tweaking the branching of regular long-chain, unbranched starch (like amylose = corn starch) solves the gooiness and delayed gastric emptying. The resulting 3-D structure of CCD makes it very soluble, non-reactive, and easy for amylase and other starch-digesting enzymes to break down into glucose – a dry powder that’s easy to manage from bottle to belly.

Another way to look at this is that CCD has all the good properties & benefits of maltodextrins (short-chain starches) and glucose, but none of the bad attributes. All dependent on the 3-D spiral-shaped tube of each chunk without that reducing end (see Figure 2).

Figure 2: Three-dimensional image of a typical highly-branched cyclic dextrin as found in CCD® (adapted from


“In vitro experiments conducted with CCD showed that it is digested by human salivary α-amylase to maltose and maltotriose, and is completely hydrolysed to glucose via the action of intestinal digestive enzymes.” [Health Canada, 2015]

CCDs are found in Nature, and have been part of the human diet since there have been humans (Choi 2009). Their safety has been reported (Choi 2009), resulting in GRAS status in the US (Generally Recognized As Safe by the US FDA), GRN 000404.

The CCD® we source for EFS-PRO is a pure, clean, well-defined source of HBCDs that has only recently become available for use in foods and supplements in the US. CCD® has been in use in Japan since 2002, and First Endurance quickly added CCD to EFS-PRO as an improvement to supply carbohydrates more rapidly and without gastric intolerance.


June 01, 2023 — Luke Bucci
Tags: research

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