Hair Anatomy 101 - A Comprehensive Guide to What Makes Up Your Locks

Have you ever wondered what your hair is actually made of? It's more than just a bundle of strands that grow from our scalp. Indeed, understanding the composition and structure of human hair can help us understand why it looks and behaves the way it does. From its internal structures to its chemical makeup, this blog will explore all aspects of what makes up our hair. We'll discuss everything from proteins to pigments, as well as how these components interact with each other to create different types of hair. So if you're curious about what exactly is in your locks, read on!

What Is Human Hair Made Of?

Human hair is a complex structure made up of several different components, including proteins, lipids, water, and trace minerals. The primary structural protein in hair is keratin, a fibrous protein that is also found in nails and the outer layer of the skin. Keratin provides hair with strength, elasticity, and resistance to damage.




Hair is formed in hair follicles, which are tiny structures in the skin that produce hair. The process of hair growth is controlled by a complex interplay of hormones and other cellular signaling molecules. Hair growth occurs in three stages: the anagen phase (growth phase), the catagen phase (transitional phase), and the telogen phase (resting phase). Each hair follicle goes through these phases independently, which is why we shed hair continuously.


The color of hair is determined by the presence of pigments called melanins, which are produced by specialized cells in the hair follicles called melanocytes. The amount and type of melanin present in hair determine its color. For example, people with blonde hair have less melanin than people with brown or black hair.


In addition to proteins and pigments, human hair also contains lipids, which help to keep hair soft and supple. Lipids are fatty substances that are produced by the sebaceous glands in the scalp. They coat the hair shaft, providing a protective layer that helps to prevent moisture loss and damage from heat styling tools.


Water is another important component of human hair, comprising around 10-15% of its weight. This water content helps to keep hair hydrated and flexible, which is important for maintaining its strength and elasticity.


The hair also contains trace amounts of minerals such as calcium, iron, and zinc, which are important for maintaining the health of the hair and scalp.


Human hair is a complex and fascinating structure made up of proteins, lipids, water, and trace minerals. Its unique composition gives it its strength, elasticity, color, and texture, and understanding the science behind hair can help us take better care of it.


What Is The Anatomy Of Hair

The anatomy of human hair can be divided into three parts: the hair follicle, the cortex, and the cuticle. The hair follicle is a small tube-like structure located in the dermis layer of the skin. It contains a bulb at its base and is responsible for producing new hair cells which then move up through the dermis layer to become part of the visible strand of hair.


The cortex is the innermost layer of the hair shaft, and it consists mostly of proteins known as keratins and melanin granules. Keratin is responsible for giving hair its strength and elasticity, while melanin gives it its color. The cortex also contains additional proteins such as cystine, sulfur-containing amino acids, and lipids that help protect and moisturize the strand of hair.



Moreover. there is the cuticle which is made up of overlapping scales that protect the cortex. The cuticle helps seal in moisture so that your hair stays hydrated, as well as protecting it from damage caused by heat-styling tools or harsh chemicals. It also helps to keep dirt and oil from entering your strands while preventing them from tangling excessively.

Hair Follicles

Human hair follicles are small tubular structures found in the dermis layer of the scalp and skin. They consist of an outer sheath known as the epidermal root sheath, which is filled with a dermal papilla. The dermal papilla is responsible for producing new cells that become part of the visible strand of hair.


The hair follicle also contains several other important components, including sebaceous glands, arrector pili muscles, and nerve endings. The sebaceous glands secrete a mixture of lipids and other substances that help to keep the hair hydrated and supple. Meanwhile, the arrector pili muscles are small muscle fibers that attach to each follicle and cause it to contract when we experience fear or stress, making our hairs stand on end. Finally, there are nerve endings that allow us to feel sensations such as itching or pain from touching our scalp or scalp-related products such as shampoos and conditioners.


Hair follicles, the tiny structures within the skin responsible for hair growth, undergo a cyclical process known as the hair growth cycle. This cycle consists of three main phases: anagen, catagen, and telogen.

In the anagen phase, which is the active growth phase, the cells within the hair follicle divide rapidly. This division contributes to the visible growth of hair in length over an extended period. The duration of the anagen phase varies among individuals and is a key factor in determining the maximum length that hair can reach.

Following the anagen phase, the hair enters the catagen phase. This is a transitional phase where cell division significantly slows down. It marks the beginning of the cessation of active growth, preparing the hair follicle for the next stage of the cycle.

The telogen phase is a resting period during which the hair follicle is dormant, and no further growth occurs. At this stage, the hair is fully formed and simply awaits the signal to shed and re-enter the anagen phase. It's during the telogen phase that hair naturally sheds, and new hair begins to grow.

The entire cycle, from anagen to catagen to telogen, is continuous and ongoing throughout our lives. This perpetual cycle explains why we consistently shed old hairs while simultaneously growing new ones. Understanding the intricacies of the hair growth cycle sheds light on the dynamic and regenerative nature of our hair, highlighting the constant renewal and transformation occurring at a microscopic level on our scalp.


Hair follicles also play an important role in providing insulation for our bodies by trapping air close to our skin which helps regulate body temperature. They can also act as receptors for hormones such as testosterone which can affect how quickly or slowly our hairs grow over time.


Understanding more about hair follicles can help us take better care of our crowning glory so that it remains healthy and beautiful all year round!

Hair Shaft

The hair shaft is the portion of the hair strand that we can actually see and feel. It is made up of three main components: the cuticle, cortex, and medulla. The cuticle is made up of overlapping scales that protect the cortex by sealing in moisture and preventing dirt, oil, and other contaminants from entering the shaft. The cortex contains proteins such as keratin and melanin granules which gives hair its strength and elasticity as well as its color respectively. Finally, the medulla is a central cavity that runs through the entire length of the hair strand filled with air pockets that provide insulation to keep our bodies warm.


The hair shaft also plays an important role in determining our hairstyle as it determines how easy or not our locks can be styled. For instance, thicker or coarser strands may require more heat or product to achieve certain styles than finer or straighter strands would. Furthermore, it can influence how long our hairstyles last throughout the day as coarse hairs are often less prone to slippage compared to finer ones.


It’s worth noting that factors such as genetics combined with lifestyle habits (such as smoking or dietary deficiencies) can also affect how healthy your hair appears over time. Regular trims at least every 6-8 weeks may help prevent split ends from forming while using quality haircare products tailored towards your individual hair type can help maintain its overall condition and appearance for longer periods of time.

By understanding what makes up our hair shafts and how they interact with their environment, we can better assess our own needs when it comes to styling and maintenance so that we can keep our crowning glory looking beautiful all year round!

The Building Blocks of Hair

Hair is composed of a complex mixture of proteins, minerals, and other substances that work together to give it its unique characteristics.


The primary component of hair is a protein called keratin, which is also found in our nails and skin. Keratin is a tough, fibrous protein that provides hair with strength and resilience. It forms the structural framework of each hair strand and helps it withstand the daily wear and tear that hair experiences.



Other proteins found in hair include collagen, elastin, and melanin. Collagen provides the hair with its elasticity and helps to maintain its shape, while elastin allows the hair to stretch and return to its original shape. Melanin is responsible for hair color, with different types of melanin-producing different shades of brown, black, blonde, and red.


Minerals such as iron, zinc, and copper are also important components of hair. These minerals help to keep hair healthy and strong by promoting the production of keratin and other proteins. Additionally, they play a role in maintaining the hair's natural moisture balance, which is essential for preventing dryness and breakage.


Overall, the complex network of proteins, minerals, and other substances in our hair work together to give it its unique characteristics, including its strength, color, and texture.

Final Thoughts

The key to achieving beautiful, healthy hair lies in taking proper care of it. To do so, regular trims and using quality hair care products tailored towards your individual needs are a must. In addition, you should also be aware of certain lifestyle factors such as smoking or diet which can have an effect on the health and appearance of your locks over time. Finally, remember that genetics play a part too when it comes to how our hair grows and looks; however, understanding the basics of what makes up our strands can help us better assess our own needs so that we can maintain our regal crowning glory!


  1. Q: What is the structure of a hair strand?

    • A: A hair strand consists of three main layers: the cuticle, cortex, and medulla. The outermost layer, the cuticle, is a protective layer of overlapping scales. Beneath the cuticle lies the cortex, containing the hair's pigment and structural proteins. The medulla, found in thicker hairs, is the innermost layer.
  2. Q: How does hair grow, and what influences its growth rate?

    • A: Hair grows from hair follicles, small structures within the skin. The growth rate is influenced by factors such as genetics, age, and overall health. On average, hair grows about half an inch per month, with faster growth during certain phases of the hair growth cycle.
  3. Q: What causes hair damage, and how can it be prevented?

    • A: Hair damage can result from various factors, including heat styling, chemical treatments, and environmental stressors. To prevent damage, minimize the use of heat styling tools, use protective products, and maintain a healthy diet. Regular trims also help prevent split ends.