The outer layer of skin, the epidermis, is a translucent layer made of cells that function to protect us from the environment. The most superficial portion contains dead skin cells that shed continuously. The deepes layer contains basal cells responsible for skin renewal. Keratin, a protein made within the cells of the epidermis, protects the skin from harmful substances such as chemical products and bacteria. The epidermis also contains cells that produce melanin, which gives the skin its colour. The epidermis is responsible for the look and health of the skin, and it holds a large amount of water. The younger the body, the more water there is in the skin. The capacity of the skin to retain water decreases with age, making the skin more vulnerable to dehydration. Keratin is the strongest protein in your skin. It also gives hair and nails their strength.

The dermis contains two types of fibres that lessen in supply with age: elastin, which gives skin its elasticity, and collagen, which provides the skin its strength. The dermis also contains blood and lymph vessels, hair follicles, sweat glands, and the sebaceous glands, which produce oil. Nerves in the dermis sense touch and pain. Collagen is the most abundant protein that makes up to 75% of the skin. This is also the “fountain of youth,” responsible for warding off wrinkles and fine lines. Over time, environmental factors and aging diminish body’s ability to produce collagen. Elastin is found alongside collagen and is responsible for giving structure to the skin and organs. As with collagen, elastin is affected by time and elements. Diminished levels of this protein can cause the skin to wrinkle and sag.

Hypodermis is mostly made up of fat. It lies between the dermis and muscles or bones and contains blood vessels that expand and contract to help keep your body at a constant temperature. The hypodermis also protects your inner organs. Reduction of tissue in this layer causes your skin to sag.

The sebaceous glands secrete sebum, an oily substance that helps the skin from drying out. Sebum reduces water loss from the skin surface, protects the skin from bacterial and fungal infections, and contributes to body odour. These glands are attached to hair follicles. When your body gets hot or is under stress, sweat glands produce sweat, which evaporates to cool you. Sweat glands are located all over the body but are especially abundant in your palms, soles, forehead, and underarms. The apocrine glands are specialised sweat glands that emit an
odour.