At the same time, many conventional cosmetics claim they deliver collagen, vitamins, and minerals to feed our skin. So do cosmetics really “get under our skin”? In fact, beauty is skin deep. Human skin is a powerful absorption organ that seems to be constantly hungry for anything that touches its surface. Just like a curious toddler, our skin grabs every available molecule, every single drop of water, every lick of makeup, and every whiff of fragrance and takes it to its cellular “mouth” to taste, chew on, and, most likely, ingest.
Oxygen, nitrogen, and carbon dioxide, as well as toxic pollutants, enter our skin via three doors: sweat ducts, hair follicles and sebaceous glands, or directly across the stratum corneum. This ability of skin to absorb chemical substances so they can be spread throughout the body is widely used in medicine. Transdermal delivery drugs for motion sickness, cardiovascular disease, chronic pain, smoking cessation, and birth control are already widely used. According to new estimates, our skin can absorb up to 60 percent of substances applied to its surface. Unfortunately, along with water, vitamins, minerals, and oxygen, skin soaks up potentially carcinogenic ingredients that increase our risk of having cancer at some point in our lives—as if breathing polluted air and eating chemicals was not enough!
To perform their magic, many cosmetic products need to push active ingredients deeper beyond the stratum corneum, the uppermost layer of skin comprised of dead skin cells. Traditionally, it was thought that hydrophilic (water bonding, or dissolvable in water rather than oil) chemicals do not penetrate deep into skin, while lipophilic chemicals (oils or oil-in-water emulsions) diffuse deeper inside the dermis.
