Magic potion?
mbalmer,
While Ben is right in saying there’s no supplement & no magic pill, there is a magic potion you could try … it’s called a frappacino!
Seriously, it sounds like you’re just running outta fuel at 2 hrs. So try this: At 1 hr. 50 min., stop and have a frappachino. You might just find that the sugar & caffine will allow you to go another hour. If nothing else, it will improve your mood because it’s tasty, and you’ve earned it.
You might also consider drinking some kind of sports drinks (Gatorade & Powerade are just fine) intermittently during your 1 hr. 50 min., to see if you can get beyond that 2 hr. threshold. In addition to running out of fuel, you could also be running low on electrolytes (i.e. sodium & potassium, but especially sodium), which will make you feel “flat” as well. And while I don’t know about you, I sweat profusely while riding – more so than while running – so I loose a lot of electrolytes (i.e., salt) while riding.
Incidentally, as a semi-retired ultrarunner, I know what it feels like to run out of fuel and electrolytes. If you don’t feed the machinery when it needs it (i.e., during a longer ride), it will fizzle, sputter, and stop. The way ultrarunners can keep going for 12, 24, or even 36 hrs. is to keep stoking the metabolic fires with fuel, and to keep replenishing lost electrolytes.
But try the frappacino trick … I’ll bet it will extend your rides by at least an hour.
Cheers,
Bert