Hair Science 101: What Is Hair Made Of?

by Viviscal Hair Expert on May 17th, 2018

Are you curious what hair is made of? Although hair grows in a countless variety of colors and textures, at a cellular level all human hair is essentially the same. And in order to grow the healthy hair you want, you have to start by understanding what your hair strands are made of. Keep reading to learn more about the building blocks of hair and what helps hair to grow.

What Is Hair Made Of?

Knowing what hair is made of can help you understand how hair grows and how to improve hair growth. We’ll go over what hair is made of, how hair grows, and give you tips on how to grow healthier hair.

What Is Hair Made Of?

The two main sections of hair are the hair shaft and the hair follicle. The hair shaft is the hair strand, and the follicle is where the strand grows. Below is what each section of hair is made of.

Hair Shaft

The hair shaft is made of a strong protein called keratin that also makes up parts of our skin and nails. Keratin, like other proteins, is formed from amino acids collected in our bodies from the food we eat. That’s why it’s crucial to consume foods high in protein for healthy hair growth. 

These are the three layers of the hair shaft:

  • Cuticle (outer layer) –  A layer of scale-like cells that overlap each other and protect your hair shaft.
  • Cortex (second layer) – A tough keratin layer that gives hair its elasticity and pigment.
  • Medulla (innermost layer) – This is the core of the hair shaft. It’s loosely packed with cells and air bubbles.



The follicle is made of different cells with varying functions. These functions include regulating hair growth, hair protection, and sebum production.

The bulb, located at the bottom of the follicle in the dermal layer of skin, anchors the hair shaft on your body. It’s made of stem cells that collect nutrients from your body to create the hair shaft.

How Does Hair Grow?

These are the three main phases of hair growth: 

  • Anagen (growth phase) – This is when most growth happens. In this phase, cells in the hair bulb are dividing fast to create new hair. Hair grows at an average rate of half an inch once a month during this period. The anagen is the longest growth cycle period, lasting anywhere from 2-6 years.  
  • Catagen (transition phase) – The catagen phase signals the end of the hair growth period. The hair strand detaches from its blood supply, ending its growth. This phase lasts about ten days. 
  • Telogen (resting phase) – Telogen is the final phase of hair growth. The follicle releases the hair strand and becomes part of normal hair shedding. That follicle will be at the telogen phase for about three months afterward.

What Helps Hair Grow


Here are some nutritional vitamins and minerals to support your hair growth:


Biotin is a form of vitamin B that helps form keratin. 


Zinc is useful for hair growth because it’s a mineral that helps tissue repair in the body. It also keeps the oil glands around your follicles healthy. A zinc deficiency can cause hair loss, so make sure you’re getting enough.

Vitamin C 

Vitamin C is an antioxidant that helps protect your hair strands from free radicals. It also helps stimulate collagen production, which keeps your hair strong and healthy. 


Calcium aids the hormones in your body responsible for hair growth. It can also help with iron absorption


Iron helps carry oxygen to the cells in your body, making it an important mineral for bodily function. Iron deficiency can also cause hair loss so it’s important to ensure you are getting proper amounts of iron. 


Niacin is a type of vitamin B that promotes healthy blood circulation and can help hair appear thicker. 

Luckily, our Viviscal Hair Growth Supplements contain all these vitamins for healthy hair. The combination of AminoMar™ plus key vitamins and minerals in Viviscal Hair Growth Supplements is scientifically proven to nourish thinning hair and promote existing hair growth*.

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What methods do you use to promote hair growth? Tell us in the comments!