In July I started using Enlyten sports strips on a recommendation from a friend. I was really suffering with the heat and humidity and these seemed to actually help. Although I have to admit I think they are easier to use while running than riding.

The Enlyten are electrolyte "strips" that you put between your cheek and your gums (look kind of like those breath freshening strips). Supposedly the electrolytes are absorbed through your cheek lining and go directly into your circulation so they bypass the whole gastric path and work faster.

Can't make any claims on if they work better than any other electrolyte supplement, but they are really convenient to carry so I usually have a pack with me. I got them at GNC. About $5-6 for two packs of 18 strips each.