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Notes on Basic Skin Biology

Basic skin biology
Our skin is the largest organ of our body, and arguably one of the most important. The skin acts as a shield between the outside world and what lies beneath, so maintaining a healthy skin barrier is important in supporting this vital function. Knowing the basics allows you to understand what the skin is, how it functions and how we can best nurture and care for it. Let’s begin with the three essential skin layers: the epidermis, the dermis and the subcutis.

The epidermis
The outermost layer of the skin and where we apply our topical products, the epidermis is less than half a millimetre thick. The epidermis undergoes a process of renewal every 28 days when new skin cells make their way to the surface. This cycle slows down as we age; incorporating a chemical exfoliator into our regime containing glycolic or lactic acid a few times a week will gently dissolve dead skin cells and speed up this turnover process.

The epidermis is coated in a very thin film of sebum (oil), amino acids and sweat, which forms an antibacterial barrier known as the acid mantle. The acid mantle is critical because it protects the skin, preventing cellular water loss (keeping skin soft and plump) and defending against aggressors such as bacteria, pollution and UV rays. 

Overusing active ingredients or switching frequently between different skincare products can strip the acid mantle, causing symptoms like inflammation and sensitivity, leading to more serious skin conditions such as rosacea, eczema, psoriasis and acne. Repair your acid mantle by avoiding skincare products containing harsh alcohols or essential oils.

The dermis
The layer of skin below the epidermis and about 20-30 times thicker, the dermis contains collagen and elastin, which are responsible for giving the skin strength, structure and elasticity. Again, as we get older the body’s natural production of collagen and elastin slows, leading to visible signs of ageing such as fine lines, wrinkles, dehydration and uneven texture. Incorporating edible collagen into your beauty routine can help to boost the body’s collagen levels and promote the synthesis of new collagen at a cellular level, as can topical products with key ingredients such as retinol and Vitamin C.

The subcutaneous or hypodermis
Below the dermis is the subcutaneous (also referred to as hypodermis or subcutis). The deepest layer of skin and closest to the muscle, it’s mostly composed of fat and fibrous tissue with the job of insulating the body and acting as a shock absorber to cushion our organs in the instance of external trauma or injury.

Each of these layers contains essential elements to our skin, while cared for as a whole through a well rounded efficacious skincare routine and anti-inflammatory diet each layer can be specifically targeted through different clinical and topical products.