WHAT HUMAN HAIR IS MADE OF Introduction

Human hair is one of the most important features of the human body. It contributes to physical appearance, beauty, identity, and personal expression. Apart from its beauty function, hair also plays protective and sensory roles. It helps protect the scalp from direct sunlight, reduces heat loss, and provides some protection against dust and other environmental factors.

Although human hair may look simple from the outside, it is actually made up of several complex substances and structures. Hair is not just a strand of thread growing from the scalp; it is a biological structure composed mainly of a protein called keratin. Other important components include water, lipids (fats), pigments, minerals, and trace elements. These substances work together to determine the strength, texture, colour, flexibility, and general appearance of human hair.

Understanding what human hair is made of is important for anyone interested in hair care, cosmetology, hairdressing, beauty therapy, and hair science.

1. Keratin: The Major Component of Human Hair

The major substance that makes up human hair is a protein called keratin. Keratin is a strong, fibrous structural protein that is also found in the nails and outer layer of the skin.

Approximately 80–90% of the dry weight of human hair consists of proteins, predominantly keratin.

Keratin is made up of smaller building blocks called amino acids. These amino acids join together to form long protein chains, which are arranged into strong structures within the hair.

One particularly important amino acid is cysteine. Cysteine contains sulphur, which allows it to form strong chemical connections known as disulphide bonds.

These bonds help hold the hair’s protein structure together and contribute to its strength and shape.

Keratin is responsible for several important characteristics of human hair, including:

• Strength and durability.

• Elasticity and flexibility.

• Resistance to physical damage.

• Hair structure and shape.

• The ability to maintain its natural form.

When hair is exposed to excessive heat, harsh chemicals, or repeated physical stress, its protein structure can become damaged. This may result in dryness, weakness, split ends, and breakage.

2. Water: An Essential Component of Hair

Water is another important component of human hair. Although hair is not a living tissue along its visible length, it can absorb and retain water from its surroundings.

Healthy hair generally contains approximately 10–15% moisture under ordinary conditions, although this varies depending on environmental humidity and hair condition.

Water plays several roles in the condition and behaviour of hair. It contributes to flexibility, softness, and elasticity.

When hair contains an appropriate amount of moisture, it is generally easier to manage, comb, and style. When it becomes excessively dry, it may feel rough, stiff, and more likely to break.

Hair can also absorb moisture from humid environments, causing the hair strand to swell. This is one reason some hairstyles change shape in humid weather.

It is important to understand that moisture and oil are not the same thing. Water provides hydration, while oils and other conditioning substances help improve smoothness and reduce friction.

3. Lipids: The Natural Fats in Human Hair

Lipids are fats and fatty substances found within and around the hair structure.

They are important because they help maintain the hair’s surface condition, flexibility, and resistance to environmental damage.

Some lipids are naturally present inside the hair fibre, while others are produced by the sebaceous glands in the scalp.

The sebaceous glands produce a natural oily substance called sebum. Sebum travels along the hair shaft and helps lubricate the hair and scalp.

The functions of lipids in human hair include:

• Helping to reduce moisture loss.

• Improving hair smoothness.

• Reducing friction between hair strands.

• Supporting the protective condition of the hair surface.

• Contributing to shine and manageability.

When the hair loses too much of its natural surface lipids, it may become rough, dull, and difficult to manage.

This is why appropriate conditioning and hair-care practices are important for maintaining healthy-looking hair.

4. Melanin: What Gives Human Hair Its Colour?

Melanin is the natural pigment responsible for the colour of human hair.

It is produced by specialised cells called melanocytes, which are located in the hair follicles.

There are two major types of melanin responsible for natural hair colour:

Eumelanin: This pigment produces brown and black shades. Higher concentrations of eumelanin generally result in darker hair.

Pheomelanin: This pigment contributes to red and yellow shades. Different combinations and concentrations of these pigments help produce different natural hair colours.

The amount and distribution of melanin determine whether a person’s hair is black, brown, blonde, red, or a combination of shades.

As people grow older, melanocyte activity may gradually decrease. When less melanin is produced, newly growing hair may become grey or white.

Therefore, hair colour is determined largely by genetics and the activity of pigment-producing cells within the hair follicles.

5. Minerals and Trace Elements in Human Hair

Human hair also contains small quantities of minerals and trace elements.

These elements enter the growing hair fibre through biological processes while the hair is developing inside the follicle.

Some minerals and elements that may be detected in human hair include:

• Calcium.

• Magnesium.

• Zinc.

• Iron.

• Copper.

• Sulphur.

• Selenium.

These substances are present in relatively small quantities compared with keratin.

Some minerals, such as zinc, iron, and copper, are important for normal biological functions involved in hair follicle activity and pigmentation.

However, the presence of a mineral in a hair sample does not automatically indicate whether a person has a deficiency or excess of that mineral. Hair mineral testing has limitations and should not be used alone to diagnose nutritional conditions.