Understanding the hair and scalp empowers you. It gives you the advantage of knowing how to take care of your hair. This means you can maintain it using the right ingredients and products in a way that benefit your hair, that you can achieve what you want with your hair. On Lush Connect you will find several articles where you will find useful scientific knowledge to understand the hair and scalp, passed onto us from our inventors and founders. This includes Mark Constantine, who is a trained in trichology, the scientific study of the hair and scalp. Mark has over 40 years experience in the hair care industry, being recognized as a leading figure in the use of natural ingredients for hair care.
The Structure of the Hair
An individual hair strand alone is made up of three layers. Think of a hair strand as a piece of sushi, the outer seaweed wrap layer holding everything in, the inner layer of rice, plump and juicy and then a filling right in the middle.
The cuticle is the outermost part of the hair shaft, like the seaweed. It is a transparent layer of hard, overlapping cells in a structure you can imagine like roof tiles. They are made of keratin, the same stuff your nails are made of. The cuticle will naturally break or become porous over time, washing, styling etc, and is usually more porous at the tips. Sebum or softeners like olive oil will keep the hair’s cuticle pliable and conditioned and protected. Essential oils like lemon or fruits like strawberries and melons will also help the cuticles to lie flat. When they’re all laying down nicely, light will reflect off of a larger surface, what we call “shiny hair”.
The cortex is like the plump rice within the sushi. It is sandwiched between the inner layer. It is the thickest layer. The cortex contains the hair’s melanin, the pigment that gives hair its colour. There are four basic colors in the hair: yellow, red, brown and black. The mix and proportions of these colors will cause the hair to “read” as reddish brown, or strawberry blonde, etc. Gray or white hairs happen because the cells that produce melanin stop producing pigment completely over time.
The cortex houses proteins that express your hair’s shape, for example, if it’s curly or straight. When hair is permed or relaxed, these proteins are disassembled, rearranged and then fixed in their new position to create the new look.
Then finally, the filling, the medulla. The innermost layer of the hair shaft is not always present, especially within finer and lighter hair. The reason for this is unknown, although with it’s presence in thicker and often darker hair, the support it offers for the structure is a factor.