The Basics of Hair Growth: Why Timing Matters in Laser Hair Removal

Laser hair removal is one of the most effective methods for long-term hair reduction. But to understand how and why it works, it’s essential to understand how hair grows and more importantly, why the timing of your treatments plays such a crucial role in the results.

The Hair Growth Cycle: Three Key Phases

Hair does not grow continuously. Each follicle cycles independently through three main phases:

1. Anagen Phase (Active Growth)

1. What Happens: Cells in the bulb divide rapidly, forming the hair shaft.
   
2. Duration: Can last from 2 to 7 years, depending on genetics and the body area.
   
3. Why It Matters: The follicle is attached to the dermal papilla and rich in melanin, making it the only phase where laser treatment is effective.
   
4. Coverage: At any given time, 10–20% of body hair is in this phase (up to 80–90% for scalp hair).
   
   

2. Catagen Phase (Transitional)

1. What Happens: The hair stops growing, and the lower part of the follicle begins to shrink and detach from the blood supply.
   
2. Duration: 2–3 weeks.
   
3. Laser Impact: Not effective, since the follicle is no longer actively growing or pigmented.
   
   

3. Telogen Phase (Resting and Shedding)

1. What Happens: The hair follicle remains dormant. The hair is eventually shed, and the cycle starts over.
   

2. Duration: Can last 2–4 months.
   

3. Laser Impact: Ineffective — there is no hair production and minimal pigment for the laser to target.
   
   

Why the Hair Cycle Affects Laser Treatment Scheduling

Since only hairs in the anagen phase respond to laser treatment, multiple sessions are required to catch each hair during its active growth cycle. Hair follicles don’t synchronize their cycles, so each session targets a different percentage of active follicles.

Treatment Timing by Area:

1. Face and neck: Every 4–6 weeks
   
2. Body (e.g., legs, arms): Every 6–8 weeks
   
3. Back or chest: Every 8–10 weeks
   
   

After each session, you may notice gradual thinning or patchy regrowth. This is a normal part of the process as more follicles are treated over time.

Other Factors That Influence Hair Growth and Treatment Results

1. Hormonal Influence

1. Conditions like PCOS, thyroid imbalance, or pregnancy can stimulate excess or irregular hair growth.
   
2. Hormonal areas (face, neck, lower abdomen) often require more sessions or maintenance treatments.
   
   

2. Body Area

1. Different areas of the body have different cycle durations. For example, facial hair cycles faster than leg hair, requiring shorter intervals between sessions.
   
   

3. Skin and Hair Color

1. Laser targets melanin, so individuals with dark hair and light skin typically see the fastest results.
   
2. For darker skin types, lasers like the Nd:YAG used in the Candela GentleMax Pro are safer and more effective due to deeper penetration and lower melanin absorption in the skin.