The Anatomy of Hair – From Root to Tip Explained
3 min reading time
Learn the biological structure of hair from root to tip. Discover how cuticle, cortex, and keratin work together for strong, healthy, and shiny hair.
The anatomy of hair – from root to tip explained
To effectively care for or treat hair, you must understand its internal structure . Each hair is a tiny biological system that lives, grows, and reacts to external influences. At the hair care academy, knowledge of hair anatomy forms the foundation of every professional result – from diagnosis to restoration.
1. The hair follicle – where it all begins
The hair root is located in the follicle , a miniature organ in the dermis. This is where the hair matrix lies, where cells divide and produce keratin.
✔ Blood vessels converge in the papilla , supplying oxygen and nutrients.
✔ The matrix cells divide rapidly and form new keratin cells.
✔ The sebaceous gland produces natural oils (sebum) that keep the hair supple.
This zone determines the growth rate, thickness and health of the hair.
2. The hair shaft – the visible part
What we see as "hair" is actually dead keratin tissue growing from the scalp. Yet, it contains three complex layers:
✔ Cuticle – the outer layer, made up of overlapping cells that protect the hair from damage.
✔ Cortex – the middle layer, where pigment (melanin) and keratin chains are located. This determines color, elasticity, and strength.
✔ Medulla – the core, present in thicker hair; responsible for insulation and volume.
Together they form a structure of strength, flexibility and shine – if properly maintained.
3. Keratin – the building block of hair
Hair consists of about 90% keratin , a protein made up of amino acids such as cysteine, serine and arginine.
✔ Keratin determines strength and resilience.
✔ Disulfide bonds within the keratin chains determine whether the hair is straight or curly.
✔ Damage to these bridges (by heat or chemicals) leads to breakage or loss of gloss.
That is why professional treatments – such as Nanoplastia, Hair Botox or Bioplastia – are aimed at restoring keratin bonds .
4. The role of melanin – color from within
The color of the hair comes from melanin pigments in the cortex.
✔ Eumelanin – provides brown and black tones.
✔ Pheomelanin – gives blonde, red and copper tones.
Graying occurs when melanin production in the follicle decreases – a natural biological process.
5. The growth and resting phases of hair
Hair grows cyclically in three phases:
✔ Anagen phase (2–7 years) – active growth.
✔ Catagen phase (2–3 weeks) – transition phase, the root shrinks.
✔ Telogen phase (3–4 months) – resting phase, after which the hair falls out.
On average, 85–90% of hairs are in the growth phase. A disrupted cycle can lead to thinning or brittle hair.
6. Protection from root to tip
The hair structure is strong, but not indestructible.
✔ The root needs oxygen and nutrients (vitamins, minerals).
✔ The cortex needs amino acids and proteins.
✔ The cuticle needs lipids and antioxidants.
Professional care focuses on each layer individually – that's what makes the difference between superficial shine and true hair health.
Conclusion: Knowledge of hair anatomy is the basis of craftsmanship
Understanding its structure is understanding hair. Professional hairdressers and colorists use this knowledge to tailor treatments precisely to the hair's biological needs. Because only those who understand how hair lives can keep it truly healthy .
