Tbh the flavor of those things is a big problem, they're hard to choke down and a glucose tolerance test requires drinking it on an empty stomach, and if you puke you have to stop and come back another day after fasting again. Looks like that's the orange flavor which is better than the grape but imo they're all nasty in the end. A more palatable mixture might be nice.
Go chug some simple syrup straight and get back to me on that one, LOL. It's not bad to put a smear on your cheek or tongue or to sip on I guess but to drink the amount you would need to for a gtt is... a LOT.