The key ingredient in most gels is a carbohydrate powder called maltodextrin. It’s a white powder that looks a lot like flour and has virtually no taste to the tongue.
The other ingredient you’ll need is fructose, often called “fruit sugar”.
For short runs, I used a small 3-oz shampoo travel container. For longer runs, I fill as much as I need in one of the 10-oz handheld running water bottles on my water belt.
