My most common rescue sugar of choice is juice boxes. Somewhere I heard of a glucose gel or drop that you put under your tongue, so I randomly decided to try holding a swig of apple juice under my tongue. I do feel like it takes effect faster, but I’m not sure I’m not imagining it. Anybody have any experience with under the tongue rescue sugar, or if there’s any science behind my theory?
The under the tongue may very well deliver faster because the area is mucous membrane and will absorb faster than swallowing and digesting the swig. Glad that works for you, way to experiment and win 
I have a small bottle of orange juice in the door of my fridge. A swig or two works great.
I tend to try to let my smarties/glucose tabs dissolve in my mouth/under my tongue if I’m having a bad low for this reason. Glucose tabs are less dense, so they do it a little better. Pretty sure the under the tongue thing will only work with glucose/dextrose though, since other sugars (fructose, sucrose, lactose, etc) will need to be digested with enzymes further along in your system.
When I was a kid my parents were taught to treat severe lows (i.e., where I was incoherent) by squirting glucose gel into my mouth and rubbing it into my cheeks. I believe the glucose gets absorbed through the mucus membranes directly into the bloodstream without needing to be swallowed and digested. Like @cardamom, I also chew up glucose tablets and hold the glucose in my cheeks if I’m trying to get it to work faster. Hard to say whether it actually works faster, but it does work as an alternative to swallowing.
Liquids are readily absorbed as soon as they’re in the mouth. Similarly, pills you’re instructed to dissolve under your tongue work much faster than pills you swallow. First, some carb breakdown occurs in the mouth, from the action of the salivary enzyme amylase (although most molecular breakdown and absorption occurs later along the digestive route). Second, the mucus membrane inside the mouth contains a great many tiny blood vessels, so the glucose (or your drug) can enter the bloodstream directly, rather than going through the time-consuming process of digestion and liver metabolism. Any sweet liquid should do the trick. At diabetic summer camp when I was a kid, they used to hang jugs of corn syrup from tree branches, for the same purpose.
I’m told honey is an excellent choice, because its glucose and fructose molecules are “unlinked,” meaning they are immediately available for absorption. (I haven’t personally noticed any faster effect, but that was in pre-CGM days. Time for a new science experiment!) By contrast, in things like table sugar or OJ, the two molecules are “bound” as sucrose, which has to wait until it’s in the small intestine for enzymes to separate its two molecules and allow for the absorption of the glucose. That’s my understanding, anyway.
Rubbing glucose gel, honey, corn syrup, etc., inside the cheek has also been recommended for serious lows because people having such serious lows may also have trouble swallowing (or be convulsing or be unconscious).
Faster ultimately gets down to the glycemic index of what you’re using as a hypo treatment.
Apple juice has a GI of around 40, honey is 58, high-fructose corn syrup is 68, while something like Karo corn syrup is over 100. Glucose tabs and gels are all around 100.
Here’s just one of many references - GI for sweet stuff
1 Like