Yesterday I did a 5.5k run in 25 degrees C and I was trying out my new fuel belt (with water bottle). I was also testing energey gels, even though it was a short enough distance for them.
The run itself went very well and I felt great at the end. I found the water bottle easy to get to and replace with the belt, so I'll be bringing that on most, if not all, of my runs from now on.
I took the first gel, grape flavored apparently, at 20mins into the run. I felt the "buzz" from it in a minute or so, but as it was a short run I hadn't really felt out of energy yet! It actually tasted of toffee or caramel, but it seemed to work. I tried another one, citrus, about 15mins after I stopped running and got a headache, probably from the caffeine! I'll keep them a bit further apart next time.