Skin is the largest organ of the body and our main protection against our environment. Skin is great at being our safeguard and defending us against hazards in the surroundings. It’s vital that we take good care of it so that it can take care of us!
Here’s a Skin 101 primer from our founders.
Our skin has 2 layers:
Deep Layer: The deep layer is called dermis. Its connective tissue is made of collagen and elastin fibers; it also has blood vessels, nerves, sweat glands, oil glands, and hair follicles.
Outer Layer: The outer layer is a thin flexible layer called epidermis and acts like armor. It is almost impenetrable, thanks to its structure. Most of its cells are called keratinocytes, born in the lower level of epidermis, growing and moving to its upper level while they mature. Epidermis is one of the few tissues that we can regenerate; it grows again naturally after injury.
What's on the surface?
A very thin layer of liquid that is made by the skin, working as a natural moisturizer and protector. It was named the acid mantle by Marchionini and Schade when it was first described in 1928 and is mildly acidic. This liquid is made of natural oils, triglycerides, water, amino acids, lactic acid, uric acid, squalene, mild acids such as fatty acids, and other molecules. The liquid comes from oil glands and sweat glands. Our skin also has a variety of normal bacteria and yeast. The liquid of the acid mantle plus the normal microbes prevent aggressive bacteria, viruses and fungus from getting into our body. The very thin layer of liquid on the surface helps keep our skin soft and flexible which reduces friction and prevents cracking.
Most of the epidermis is keratinocytes, cells that manufacture and fill with a fibrous protein named keratin , flattening out as they mature and move to the surface of the skin. The cells also give off fluid that acts as cement, attaching the cells together so their barrier is more effective. The surface layer of epidermis is the stratum corneum and is protected by the acid mantle, the liquid coating of natural moisturizing factors.
Skin and its appendages. Gray's Anatomy, 41st edition, 2015. pp 141-161.
Surface Skin pH: A Protective Acid Mantle. G Yosipovitch, HI Maibach. Cosmetics & Toiletries Magazine, Dec 1996, Vol 111, No. 12, P 101.
pH Directly Regulates Epidermal Permeability barrier Homeostasis and Stratum Corneum Integrity/Cohesion. J-P Hachem. J of Investigative Dermatology. Vol 121, issue 2, p 345-353.
The Acid Mantle of the Skin as Determined by Gas Chain Measurements. 1928. Klinische Wochenschrift. A Marchionini, H Schade. Translated in book: "pH and Skin Care" M Schmid-Wendtner, HC Korting. ABW 2007, Germany.
Understanding the Acid Mantle. From website: Naked Chemist 10/27/2014
Our Skin Needs An Acid Mantle. Website: CureZone
Medically reviewed on 7/6/2016