About your hair

Hair is made up of a very simple structure; it is made up of the tough protein keratin. Keratin forms the strength of your hair, nails, and the outer layer of our skin.

Keratin is a large molecule that is made up of smaller units, these are called amino acids and they join together to form a chain.

Your hair is made up of different layers and structures; although the structure is simple these different layers and structures result in different people have different types of hair.

Hair growth

Different types of hair will need to be treated differently and it is important to understand exactly what your hair needs to keep it in the best possible condition.

The hair growth cycle works in the same way for everyone, however, different factors can change the rate in which your hair grows and how healthy it is. Leading a healthy lifestyle and reducing stress can help with your hair growth cycle.

It is important to understand the hair growth cycle, as this will help you identify problems that you could encounter with your hair.

Hair loss

There is no single cause of hair loss and there are many different factors that are associated with excessive hair loss. These different factors can cause different types of hair loss.

Some types of hair loss, such as stress related hair loss are not permanent and your hair will begin to resume its normal growth cycle, with no treatment needed. Other types of hair loss, such as hormonal hair loss are permanent; however, there are treatments that can help with your hair loss.

It is very important to understand your hair and its growth cycle and structure as this could help you prevent hair loss in the future.

If you are experiencing any form of hair loss and would like some more information, please feel free to contact us for a no obligation consultation where one of our hair loss specialists can help to answer any questions you may have.

Types of Hair

There are many different types of hair, all of which have their own properties. Knowing your hair type is very important as it can help you decide what is the best way to care for your hair. Your lifestyle and how you care for your hair can help with your growth cycle , and in some cases help to reduce the risk of hair loss.

Hair structure

Our hair structure is mainly made up of the tough protein keratin. However, our hair fibres have a structure that consists of several different layers.

There are three layers to our hair:

  1. Cuticle, which consists of several layers of flat, thin cells
  2. Cortex, which contains the keratin, bundled in a cell-like structure
  3. Medulla, a disorganised and open area at the fibre’s centre

The cuticle is the outer covering of the hair, its structure slides as the hair swells and is covered with a single molecular layer that makes the hair repel water.

Each layer plays a part in the characteristic of our hair. The medulla is not always present and is an open, unstructured region.

The cortex, or middle layer of the hair, is the primary source of mechanical strength and water uptake. The cortex contains melanin, which colours the fibre and determines the colour of your hair, based on the number, distribution and types of melanin granules. The shape of these follicles determines the shape of the cortex, and the shape of the fibre relates to how straight or curly your hair is

People with straight hair have round hair fibres, and people with oval and other shaped fibres tend to have more wavy or curly hair.

Classification of hair

There are many ways to classify hair, but the Andre Walker system is the most widely used to classify hair.

These are the 4 main types of hair, all of which come with subcategories. The subcategories go more in-depth to the type of hair, what it looks like, how susceptible to damage it is and how easily it is to tame and style.

Type 1: Straight
1a Straight (Fine/Thin) Hair tends to be very soft, shiny, oily, poor at holding curls but difficult to damage
1b Straight (Medium) Hair characterised by volume and body
1c Straight (Coarse) Hair tends to be bone-straight and difficult to curl. Common in Asian women
Type 2: Wavy
2a Wavy (Fine/Thin) Hair has a definite ‘S’ pattern and is usually receptive to a variety of styles
2b Wavy (Medium) Can tend to be frizzy and a little resistant to styling
2c Wavy (Coarse) Frizzy or very frizzy with thicker waves; often more resistant to styling
Type 3: Curly
3a Curly (Loose) Curly hair that usually presents a definite ‘S’ pattern and tends to combine thickness, fullness, body and/or frizziness
3b Curly (Tight) As 3a but with tighter curling like a spiral
Type 4: Kinky
4a Kinky (Soft) Hair tends to be very fragile, tightly coiled and can feature curly patterning
4b Kinky (Wiry) As 4a but with less visible (or no) curly patterning
4c Kinky (Wiry) As 4a and 4b but with almost no defined curl pattern

Hair type 1: Straight hair

Type 1 is straight hair, which reflects the most sheen. Straight hair is also the most resilient and oiliest of all the hair types. Straight hair is very hard to damage, and also difficult to curl. This is because the sebum in this hair texture easily spreads from the scalp to ends without curls or kinks.

Hair type 2: Wavy hair

Wavy hair has a texture and sheen between straight and curly hair and is likely to become fizzy. Fine wavy hair can be tamed and easily styled, however, medium and coarse hair can be hard to style.

Hair type 3: Curly hair

Type 3 is curly hair, which, is known to have an S-shape. The pattern of the hair resembles an ‘S’ shape and sometimes a ‘Z’ shape. This type of hair is usually voluminous, climate-dependent, and damage-prone. If your curly hair lacks proper care you may end up with less defined curls.

Hair type 4: Kinky hair

Kinky hair features a tightly coiled curl pattern is often very fragile with a high density. This type of hair shrinks when wet because it has fewer cuticle layers than other hair types and because of this, is more susceptible to damage.


Hair structure

Hair is made up of different layers and structures.

It is the tough protein keratin that forms the strength of your hair, nails and the outer layer of skin. Keratin is a large molecule made up of smaller units called amino acids, which join together to form a chain.

The Hair Root

The epidermis, as shown in the diagram below, is the outermost layer of the skin. Each hair arises from an indentation on the epidermis. Hair is made up of two parts, the hair follicle and the hair shaft.

Hair Follicle

The hair follicle is the point from which the hair grows.

  • The terminal part of the hair follicle within the skin is called a hair bulb.
  • The hair bulb is the structure formed by actively growing cells.
  • These cells produce the long, fine and cylindrically-shaped hair fibres.
  • The hair bulb has special cells which produce the pigment that gives hair its colour.
  • The pigment is called melanin and the cells producing it are known as melanocytes.
  • Androgens, which are receptors for the male hormones, are located on the cells of this structure.
  • The dermal papilla that feeds from the bloodstream provides nourishment to form new hair and is found at the base of the hair bulb.
  • Within the skin, internal and external root sheaths cover the hair follicles.
  • The outer rooting of a hair follicle has a continuous growth cycle along with the epidermis.
  • Adjacent to the hair follicles are glands.
  • The most important one of these glands is the sebaceous gland, as it produces and secretes the natural oils which lubricate the hair.

Hair Shaft

The part of the hair seen above the skin is called the hair shaft.

  • The hair shaft is made up of dead cells that have turned into keratin and binding material, together with small amounts of water.
  • This structure explains why we do not feel any pain whilst our hair is being cut.
  • The hair shaft is formed of three layers:
    • The medulla – the deepest layer of the hair shaft, only seen in large and thick hairs.
    • The cortex – the middle layer of the hair shaft which provides the strength, colour and texture of a hair fibre.
    • The cuticle – the outer layer of the hair shaft is thin and colourless. It serves as protection to the cortex.

Hair growth cycle

Each hair follicle goes through a constant cycle of growth, rest and finally shedding. This cycle continues over and over until something else happens to prevent the follicle from forming new hair. Understanding the hair growth cycle will help you identify problems that you may encounter with your hair.

Genetics determine hair follicles’ pattern of growth and rest. As we age, hair follicles are programmed to stop producing hair and spend more time in the resting stage.

Learn more about how genetics affect your hair growth → 

The hair cycle is also affected by other external and environmental factors, such as lack of sleep, or stress. Leading a healthy lifestyle and trying to keep stress levels to a minimum are sure-fire ways to speed up the rate at which hair grows. Physical activity also encourages your body circulation including your scalp, promoting hair growth.

What other environmental factors can affect hair growth?  

What are the stages of the hair growth cycle?

There are 3 stages of hair growth in the cycle, from actively beginning growth from the root to hair shedding:

1.   Anagen, or growing stage

  • The anagen stage is the growing period of a hair follicle
  • This stage typically lasts about 3 to 5 years
  • The anagen phase constitutes about 90% (1000 days or more) of the growth cycle

2.   Catagen, or intermediate stage

  • The catagen stage is the intermediate period of hair growth
  • Hair follicles prepare themselves for the resting phase
  • It lasts around 1-2 weeks
  • During this phase, the deeper portions of the hair follicles start to collapse

3.   Telogen, also known as the resting or shedding stage

  • The telogen stage is the resting and shedding period of the hair cycle
  • It usually lasts 3 to 4 months

At the end of this period, older hairs that have finished their life will fall out and newer hairs will begin to grow