If I make a simple transdermal out of water with just water-soluble ingredients, with DMSO as the carrier, and I added some amount of glycerin to help "thicken" it a bit, purely for ease of application, would this negatively effect the absorption of ingredients? I ask because I read glycerin penetrates only the first few layers of skin (not all 7), and then sits there drawing water into it. I'm wondering if instead of the ingredients penetrating all layers to the tissue with the help of DMSO as would normally happen, the glycerin will absorb the water (with the ingredients diluted into it) while it sits in a more superficial layer of skin, and prevent it from going as deep as it should.
I also wondered if thickening the formulation with some cellulose derivative would be better, but those basically work by absorbing mass amounts of water when you mix them in. They also doesn't penetrate the skin at all--so, in theory most of the transdermal would just sit atop the skin with the cellulose it was absorbed into. Is this correct?
Sorry if these questions are a bit involved.