Q: Don't I need even a small amount of glucose to absorb hydration?
A: Our research suggests NO.

Our founder has spent the best part of 20 years reading through various types of studies, dissecting them and attempting to work out how they come up with a conclusion that suggests hydration absorption requires glucose. Any study on sports nutrition that has a definitive conclusion automatically throws up some red flags.
The first thing to look for is who sponsored the study.  The second thing is to understand what the actual study is trying to show.  In some studies, they provide varying types of beverages to 20 healthy males at rest.  Why at rest?  If you are going to do a study on fluid delivery and promote it to the demographic that it is designed for, why would you do the study at rest? Wouldn't doing the study at an elevated heart rate while the subjects are experiencing sweat loss be a better representation?
What is interesting is that many studies use the words fluid delivery and not fluid absorption. 
Regardless of the percentage of glucose, whether it's 3%, 6% or 9%, the message the manufacturer of these beverages is sending is that everyone is exactly the same. The message is that we all need to consume the same volume of fluid, we all need the same amount of sodium and we all require the same amount of fuel. So whether the temperature is 30 degrees or 95 degrees the expectation is that we drink the same volume of fluid regardless of the fact that we will be losing very different volumes of sweat. Hydration is based on replacing an amount of fluid that the stomach can comfortably tolerate at elevated heart rate, which is dictated by the intensity (workload) and the environmental conditions. Alter either one of those factors and the amount of fluid you consume will change. 
Our founder has over 1500 studies that show that we sweat varying amounts even at the same intensity in the same environmental conditions, therefore the amount of fluid we need to consume is not set to a specific amount.  Instead, it is based on how much sweat we are losing.  We have varying concentrations of sodium in our sweat and therefore require varying amounts of sodium in our fluid to address our unique and very individual requirements. AND we have very different requirements when it comes to the amount of fuel we require to address our energy expenditure, which is not based on how much we weigh but is based on how fast we are going.
Removing the calories from your drink allows you to alter the volume of fluid you consume based on the amount you are losing at the time, which is dictated by the changing weather conditions. This means the athlete is not drinking too much when it's cold, which is likely to compromise the stomach, yet be able to drink a greater volume of fluid in hotter conditions to address their increased fluid requirements. Removing the calories from your fluid also allows the athlete to increase the amount of sodium without adding all the extra sugar. Powdered sports drinks, with their set amount of sodium, do not come close to replacing the majority of athletes' requirements when it comes to sodium loss.  
You can read all the studies you want on sports nutrition but the fact is not one of them can confidently come to a conclusion, simply because there are so many different variables to consider. If a study has come to a conclusion, it's likely they had a set agenda in mind even before beginning the study. Any published article, when it comes to sports nutrition, is relevant only to the subjects in that study. It is relevant only to their physiological makeup, it is relevant only to their unique digestive system, it is relevant only to the intensity at which the study was performed at and it is relevant only to the environmental conditions the test was performed in. What needs to be made very clear is that the conclusion of any published article will change if any of the factors above change, meaning if you alter the environmental conditions by 20 degrees, either way, then the results will change, therefore resulting in a different conclusion.