6.3 Growth Cycles, Growth Patterns and Wave Patterns

Growth Cycles, Growth Patterns and Wave Patterns

Exam Focus: Two clusters of items come from here. First the numbers: 3–5 years anagen, about 90% in anagen, half an inch per month, 50–100 hairs shed daily. Second the practical distinction between growth pattern, wave pattern, texture and density — four different properties that candidates routinely confuse.

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1. Hair Growth Life Cycles & Daily Shedding Rates

Hair follicles cycle continuously through three distinct biological phases:

┌─────────────────────────────────────────────────────────────────────────────┐
│                          HAIR GROWTH LIFE CYCLES                            │
└─────────────────────────────────────────────────────────────────────────────┘
                                     │
        ┌────────────────────────────┼────────────────────────────┐
        ▼                            ▼                            ▼
┌───────────────────┐      ┌───────────────────┐      ┌───────────────────┐
│   ANAGEN PHASE    │ ───> │   CATAGEN PHASE   │ ───> │   TELOGEN PHASE   │
│ (Growth Phase)    │      │ (Transitional)    │      │ (Resting Phase)   │
├───────────────────┤      ├───────────────────┤      ├───────────────────┤
│ • 3 to 5+ years   │      │ • 1 to 2 weeks    │      │ • 3 to 6 months   │
│ • Active mitosis  │      │ • Bulb detaches   │      │ • Resting/shedding│
│ • 90% of scalp    │      │ • < 1% of scalp   │      │ • 10% of scalp    │
│ • ~0.5 in./month  │      │ • Club hair forms │      │ • Pushed by anagen│
└───────────────────┘      └───────────────────┘      └───────────────────┘

1. The Anagen Phase (Active Growth Phase)

• Characteristics: Matrix cells in the hair bulb undergo rapid mitosis, synthesizing new keratin. The hair shaft grows upward through the follicle.
• Duration: Lasts between 3 to 5 years (can extend up to 7–10 years depending on genetics).
• Rate of Growth: Healthy human scalp hair grows at an average rate of approximately 0.5 inch (1.25 cm) per month (about 6 inches per year). Scalp hair grows faster between the ages of 15 and 30 and slightly faster in warm summer months.
• Population: Approximately 90% of all scalp hair is in the active anagen phase at any given moment.

2. The Catagen Phase (Transitional Phase)

• Characteristics: The active growth stops. The follicle canal shrinks, and the bottom of the hair root detaches from the nourishing dermal papilla. The lower part of the root contracts to form a rounded, hard keratinized knob known as a club hair.
• Duration: A brief transitional period lasting 1 to 2 weeks.
• Population: Less than 1% of scalp hair is in catagen at any given time.

3. The Telogen Phase (Resting Phase)

• Characteristics: The final resting stage of the hair cycle. The club hair remains in the follicle until it is shed naturally during washing/brushing or is pushed out by a new emerging anagen hair forming below.
• Duration: Lasts approximately 3 to 6 months.
• Population: Approximately 10% of scalp hair is in the resting telogen phase.

Normal Daily Shedding Rates

• It is completely normal and physiological to shed 50 to 100 hairs per day from the scalp.
• Eyebrow and eyelash hairs have a much shorter anagen growth phase (typically 3 to 4 months), explaining why they do not grow to extreme lengths like scalp hair.

2. Natural Growth Patterns

Growth pattern is the direction in which hair grows out of the scalp, and it is fixed. You cannot cut it out, and fighting it produces haircuts that will not sit.

Identify growth patterns on dry hair before you begin, because wetting the hair and combing it flat conceals them. This is the first assessment in the consultation sequence in Chapter 7.

3. Wave Pattern

Wave pattern describes the shape of the hair strand along its length: straight, wavy, curly or coily. It correlates with the cross-sectional geometry of the follicle — round follicles produce straighter hair, oval and flattened follicles produce increasingly curved hair.

Wave pattern drives service decisions throughout this guide:

• Cutting. Curly and coily hair shrinks as it dries, sometimes dramatically. A cut executed on wet curly hair without accounting for shrinkage will finish far shorter than intended.
• Chemical texture. Chapter 10's rod size, wrapping pattern and relaxer strength decisions all begin with wave pattern.
• Colour. Coily hair is often more porous at the bends of the curl, where the cuticle is naturally more raised, so colour and lightener can grab unevenly.
• Styling. Chapter 9's thermal, pressing and braiding sections are organised around wave pattern.

4. Four Properties Candidates Confuse

A client can have fine texture and high density — many thin hairs — or coarse texture and low density. Confusing the two produces the classic formulation error: treating a client with a lot of fine hair as though the hair were strong, and overprocessing it.