I addressed this the other day, but I think I need to say it again as I've seen a three posts or e-mails in the last two days referring to glycerin as oil soluble. Glycerin is water soluble. It is the very epitome of being water soluble. Let's take a look at the chemistry - and don't zone out on me as this is interesting!
why oil and water don't mix. The reason for this is that water is polar - meaning it has a slightly more negative charge near the oxygen atom and a slightly more positive charge near the hydrogen atoms. (The red is oxygen, the white is the hydrogen.)
Like dissolves like means that something polar will dissolve something polar. Water is polar and glycerin is polar, so we should expect that glycerin will dissolve in water. If something dissolves in water, we call it water soluble. As its solublity is really high in water - it's called "completely soluble" so add as much as you want - we can call this water soluble.
If you want to see if what I've written is valid, get a glass of room temperature-ish water. (Solublity is generally tested at 25˚C, but we can do it at room temperature of 18˚C to 20˚C.) Add some glycerin to it - let's say a dollop from your bottle - and mix. Add some more and mix. And so on. If it remains mixed, then it's water soluble.
If you want to test if something is water soluble, get a glass of water and add the ingredient. Mix. Let it sit for a bit at room temperature and see what happens. If it floats to the top or sinks to the bottom and you can see it's a different thing from the water - for instance, it's a white solid or a yellow liquid - that means it didn't mix in and isn't soluble. Do the same for something being oil soluble.
Can I ask the question? Where are you getting the idea that glycerin is oil soluble? It's definitely coming from somewhere! Could it be this post at Livestrong that calls it "glycerin oil", something I have never heard it called before? Or this post from eHow that does the same thing?
Glycerol: Jack of All Trades
Glycerine: An overview
Powerpoint from the University of Idaho
My chemistry classes