Most of us understand that certain products like petroleum jelly (called an ‘occlusive’) lays on top of the skin and seals in moisture, but does not penetrate down into the dermis at all.  We’ve also observed that a product like alcohol seems to absorb into the skin almost instantly.

What’s up with that?  How can we be sure that all these great ingredients are even getting into our skin and how deeply?  Can some of them reach our bloodstream, and if so, is that a good or a bad thing?

So we decided to address the issue and take a look at how skin care ingredient penetration happens, and how you can best utilize this knowledge to make the most of your skin care regimen.

PERMEABILITY OF SKIN CARE INGREDIENTS

After you apply any treatment serum, cream or hydrator, that product comes in first contact with the skin layer known as the stratum corneum.  What happens next depends on both the particle size and what we call ‘active’ properties of the specific ingredients.  There are 3 different outcomes based on those two factors.

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:

Outcome #1:

If the ingredient particles are sufficiently small and the actives are permeable, these particles will be absorbed completely by the skin cells and metabolically processed.  Following that, after a period of time, the ingredients will be released from the skin cell and will enter the bloodstream via circulation by differing percentages.  The most common of these are Vitamins like C, A and E.  Topical skin patches like birth control and Nicotine are also good examples of how this works.

Outcome #2:

Some active ingredients are too large to be absorbed into skin cells, but are still small enough that they will move down and around the skin cells for a period of time.  Later on, after another time period these ingredients will also enter the blood and lymph systems and then be excreted from the body.  PEPTIDES are a good example of these.  Peptides have been clinically shown to be effective due to this process, (called ‘Dermo-Epidermal Junction or DEJ)

Outcome #3: 

If the active ingredients are too large to be permeable into skin cells or move between the skin cells, they can still be temporarily absorbed by glands in the substructure of the skin. This process is known as ‘appendageal absorption’, which means that there are what’s called ‘reservoir effects’, which simply means that whatever that substance is may be stored within the glands (we have many glandular structures within the dermis) over a period of time before being released into the bloodstream.