The Science of Laser Hair Removal

Laser hair removal is often described simply as “destroying the hair follicle”. In reality, it is a highly controlled interaction between light, pigment and heat — governed by a principle known as selective photothermolysis.

Light as a selective tool

Hair removal lasers are calibrated to emit light at wavelengths that are preferentially absorbed by melanin, the pigment within the hair shaft and follicle.

When this light is absorbed, it is converted into heat. This heat diffuses into the follicular structures responsible for hair growth, impairing their ability to regenerate. 

Crucially, the surrounding skin absorbs far less of this energy, allowing treatment to occur without widespread tissue damage.

This balance — between sufficient energy to disable the follicle and sufficient control to protect the skin — defines the effectiveness of the treatment.

Why wavelength matters

Different wavelengths of light behave differently within the skin.

Shorter wavelengths, such as the 755 nm Alexandrite laser, are more readily absorbed by melanin and are therefore highly efficient at targeting hair. 

Longer wavelengths, such as the 1064 nm Nd:YAG laser, penetrate deeper into the skin and are less absorbed by epidermal pigment, making them safer for darker skin tones. 

This distinction is fundamental.

It allows the treatment to be adjusted not only to the hair itself, but to the relationship between hair and skin, which varies significantly between individuals.

Thermal damage and biological response

The aim is not instantaneous removal, but progressive follicular disruption.

The thermal energy delivered to the follicle damages key structures such as the hair bulb and bulge, which are responsible for regeneration. Over time, this results in:

• delayed regrowth
• finer, weaker hair
• eventual long-term reduction

Why timing is critical

Hair grows in cycles: anagen (active growth), catagen (transition), and telogen (resting).

Laser energy is most effective during the anagen phase, when the hair is actively connected to the follicle and rich in melanin.

Because not all hairs are in this phase simultaneously, multiple treatments are required to progressively target each cycle.

A controlled, non-invasive system

Modern systems such as GentleMax Pro deliver this energy with a high degree of precision, incorporating cooling mechanisms to protect the epidermis and maintain patient comfort. 

The result is a treatment that operates at a cellular level, without disrupting the integrity of the skin’s surface.