HOW MUCH PRODUCT ACTUALLY GETS IN TO THE SKIN?

To understand how much product actually gets into your skin, you first have to have a basic understanding of the skin.

       Skin is made up of 3 layers.  The first layer (the one we see) is called the “Epidermis”.  The outermost layer of the Epidermis, called the “Stratum Corneum”, is made up of cells high in keratin, a substance that helps maintain skin hydration by reducing moisture loss.  In effect, keratin contributes to the creation of a semi-waterproof barrier.

     The Stratum Corneum is comprised of flat dry layers of skin cells that overlap much like the scales of a fish.  Besides maintaining hydration, this layer also helps to prevent damage to vital organs from UV rays, pollution, wind and yes, water.  The Stratum Corneum is considered hydrophobic (water fearing).  The pH of the surface of the skin is between 4.5 and 5.5 which means it is slightly “Acid” (or hard).

     Whereas the Stratum Corneum is considered Hydrophobic, the epidermis is actually Hydrophilic (water loving). 

     The middle layer is called the “Dermis”.  This is where the blood vessels of the skin are. 

     The bottom layer is called the “Subcutaneous Tissue”.  This layer is what gives the skin its cushion and form.  It is between the Subcutaneous Tissue and the Dermis where new skin cells are born.  We call this the “Basal Layer”.  The area we are going to focus on is the Basal Layer up to the Stratum Corneum.

     When new skin cells are formed, they resemble plump grapes.  As they slowly make their way up to form the Stratum Corneum (approximately 30 days), they began to loose moisture and flatten out to create the skins armor.

     Since the Stratum Corneum is Hydrophobic, the only way products can penetrate this armor is by prolonged exposure to a watery substance (think about what happens to your fingers when you wash dishes).  Basically what’s happening is, the pH of the skins surface has changed from being in an acid (hard) state of 4.5 to 5.5 to and alkaline (soft) state of 7.0 plus. 

     The best way to achieve the optimum condition for product penetration is to use a water activated cleanser for approximately 2 minutes or longer. Keep in mind that there is a very short window of opportunity to get products to penetrate before the skin becomes acid (hard) again (usually 2-5 minutes), so after rinsing the cleanser off, one needs to quickly pat some of the moisture from the skin and begin applying the product as quickly as possible.  It is actually best if there is a small amount of water still on the skin.

     Another factor to take into consideration when determining if products penetrate is the pH of the product itself and its molecular size.

     Almost all creams have a pH similar to skin (4.5 to 5.5) therefore, once the product comes into contact with the skin, the product will automatically take the skins surface back to its “Normal pH”.  In this case, very little product is able to penetrate.  To determine if a cream has an acid pH, simply look at its color and texture.  If your cream is thick like mayonnaise and white (not clear), chances are the pH is very low. 

     The molecular size of the substance is even more important than its pH.  It is proven that for substances to penetrate the Stratum Corneum layer, its molecular weight has to be 500 Daltons or less.  Almost all face creams are at least 800 Daltons or higher.  This is due to the thickness of the cream.  Clearer more fluid like substances generally have a molecular weight smaller than 500 Daltons, making them easier to penetrate the skins natural barrier.

     Once the substance has penetrated the hydrophobic Stratum Corneum, it is easily absorbed into the hydrophilic Epidermis where it can now do its job.