Simple stated, stay with a small molecule size for best penetration. Microderms, commonly known as Microdermabrasion can often help to slough off old dead skin we need to shed and ultimately provide a better canvas for those high performing ingredients to penetrate like peptides and serums.
Here is some great info from futurederm:
When you apply a serum, lotion, or cream, it encounters the uppermost layer of skin, which is called the stratum corneum. Depending on the size and chemical properties of the ingredients, three different things can happen:
1: Small and Permeable: Absorbed by Skin Cells
If the ingredients in your product are small and permeable, they will be uptaken by skin cells and processed. After a period of time, the ingredients will be secreted out of the skin cells and will enter the circulation. This includes ingredients like L-ascorbic acid (vitamin C), tocopherol acetate (vitamin E), and retinol (vitamin A).
2: Large and Non-Permeable: Goes Between Skin Cells
If the ingredients in your product are too large to be uptaken by skin cells, they will move between the skin cells for a period of time. After a while, these ingredients will also enter the circulation and be excreted from the body. These include peptide ingredients like Matrixyl 3000, which have been shown to work at a space between skin cells known as the dermo-epidermal junction (DEJ)
3: Large and Non-Permeable: Is Temporarily Absorbed by Glands
If the ingredients in your product are not absorbed by your skin cells, they may also be temporarily absorbed by some glands in a process known as ”appendageal absorption”. In this process, there are “reservoir effects” in which substances may be stored within the glands for absorption over time before being released into the bloodstream. This includes ingredients like aluminum, which is the reason for some of the controversy surrounding aluminum-containing deodorants.
View futurederm's site