So let's take a moment to take a look at the basics of hair chemistry and biology!
This is a basic picture of your hair follicle, the essential growth structures for hair.
We have vellus hair, the light, only occasionally pigmented hair that seldom gets longer than 2 cm (a little less than an inch). This is the hair that grows on your upper lip, your forehead, and all over your body.
And we have terminal hair, the longer, coarser, pigmented hair that grows on our scalp, eye brows, and eyelashes before puberty and pretty much everywhere else after puberty. It is developed in those other areas from vellus hair. Terminal hair has a medulla, which is the hard core in the centre that gives that hair structure; vellus hair does not, which is why it is so short and light.
As you can see from the picture, the sebaceous gland is right beside the hair follicle, which explains how our hair gets oily!
Our main focus when creating hair care products is to remove the sebum and soil while shampooing, and repair and maintain the keratin of our cuticle.
Let's take a look at the structure of our terminal hair (tomorrow) then take a look at the growing cycles! But first - what the heck is adsorption and substantivity? Join me in about 20 minutes for more on this topic!