As your body’s first line of defence against the environment, the skin is intricately designed to keep your internal organs safe and healthy. It is your largest organ.
The skin is made up of 3 layers: the upper defensive epidermal layer, the middle collagen-filled dermis and the bottom cushioning subcutaneous layer.

In the lowest layer you can find the subcutaneous tissue. Used mainly to store fat, it contains larger blood vessels which can provide nutrients to the skin.
The dermis is the second layer up. Here resides strings of collagen and elastin surrounded by a matrix of molecules. This is the part of the skin that detects touch and heat, in addition to housing the roots of hair follicles and sweat glands. Blood vessels run through the dermis which provide essential nutrients and nourishment to the epidermal skin cells.
The epidermis is the upper layer of the skin. It is further split into 5 different layers, each with its own unique characteristics and functions. Skin cells are formed in the lowest layers called the stratum basale. Here the cells can rapidly replicate themselves as they still possess a nucleus which stores DNA. Melanocytes, the cells that create melanin to give colour to the complexion, are also found in this layer. The skin cells in the stratum basale move up through the epidermal layers towards the surface, going through subtle changes at each stage. In the upper layers the cells lose their nucleus and become flat, dead skin cells called keratinocytes. These continuously flake off to reveal newer, fresher cells beneath. The stratum corneum is the top layer of the epidermis, made up entirely of dead skin cells in brick-like layers. Between the skin cells there is an ocean of lipids (oil-soluble molecules) acting as mortar. The lipids are made up of ceramides, cholesterols and fatty acids. This structure provides an impermeable barrier against the environment, protecting the skin from pathogens and blocking the loss of water molecules. The pH of the skin is around 4.5-5.5; slightly acidic due to a layer of sebum which hinders alkaline-loving pathogens.

What are Skin Types?
Your skin type describes the skin you were born with. It stays constant throughout your life, although the condition of our skin can  vary greatly according to the various internal and external factors it is subjected to. as your skin matures. There are four basic types of healthy skin: normal, dry, oily and combination skin.You will always get the best results with products that are tailored to your skin type. 

Normal - Eudermic skin
Normal’ is a term widely used to refer to well-balanced skin. The T-zone (forehead, chin and nose) may be a bit oily, but overall sebum and moisture is balanced and the skin is neither too oily nor too dry.

How to identify normal skin
Normal skin has:
* fine pores
* good blood circulation
* a velvety, soft and smooth texture
* a fresh, rosy colour uniform transparency
* no blemishes 
*  it is not prone to sensitivity.
As a person with normal skin ages, their skin can become dryer.

Dry skin - Xerosis
Dry’ is used to describe a skin type that produces less sebum than normal skin. As a result of the lack of sebum, dry skin lacks the lipids that it needs to retain moisture and build a protective shield against external influences. This leads to an impaired barrier function. Dry skin exists in varying degrees of severity and in different forms that are not always clearly distinguishable.
Significantly more women suffer from dry skin than men and all skin gets dryer as it ages. Problems related to dry skin are a common complaint and account for 40% of visits to dermatologists. 

What are sub-conditions?
Sub-conditions are the concerns that affect your skin that can be improved through application of the right products. They include surface dryness, ruddiness/couperose/spider naevi, sensitivity/over-processed skin, rosacea/dermatitis/eczema/psoriasis, large pores/winer pores and hyperpigmentation/melasma.

Surface Dryness
It is very common for the top layer of skin on your face to become dried out - this is referred to as surface dryness. When the temperature outside drops or when dry wind blow or when you spend lots of time in airconditioned enviroment,your skin reacts by releasing its moisture - boom, you now have surface dryness. Your skin can also become dry by using the wrong type of products.

Ruddiness/Couperose/Spider Naevi

It is a condition in which brown patches appear on the face.
Chronic: if untreated, it can last for years or be lifelong
Melasma can be due to hormonal changes during pregnancy or from sun exposure. Women are much more likely than men to develop this condition.
The brown or grey-brown patches of melasma appear most often on the cheeks, forehead, nose and chin.
In women, melasma often fades on its own after pregnancy or after an affected woman stops taking contraceptive pills. Skin lightening creams can help lasting melasma.