The Science Behind the Challenges of Laser Hair Removal on Grey Hair and the Limitations of Colouring Solutions

By Raymond Schoeman

Laser hair removal has gained immense popularity as a highly effective method for permanent hair removal. However, the success of the treatment depends significantly on the colour of the hair being targeted. While laser hair removal can produce excellent results for dark and pigmented hair, it presents challenges when dealing with grey or white hair. In this article, we will delve into the scientific reasons behind the difficulties of laser hair removal on grey hair and explore why attempts to colour the hair before the procedure are ineffective.

Understanding Laser Hair Removal

Laser hair removal operates on the principle of selective photothermolysis. A laser emits a concentrated beam of light that is absorbed by the pigment (melanin) present in the hair follicles. The absorbed light energy is then converted into heat, effectively killing the dermal papilla and inhibiting hair growth.

The Role of Melanin

Melanin, the pigment responsible for the colour of our hair and skin, plays a crucial role in laser hair removal. Darker hair contains higher concentrations of melanin, making it an ideal target for the laser. When the laser light is absorbed by melanin, it effectively heats up the follicle, leading to its destruction.

The Challenge of Grey Hair

Grey or white hair, on the other hand, lacks melanin or has significantly reduced levels. As a result, the laser struggles to target the hair effectively. Without sufficient melanin to absorb and convert the light energy into heat, the laser cannot destroy the dermal papilla effectively. Consequently, traditional laser hair removal techniques tend to be less successful on grey hair.

The Science Behind Melanin

To understand why melanin is essential for laser hair removal, it’s crucial to explore its role in the hair growth cycle. Melanocytes, specialized cells located at the base of the hair follicle, produce melanin. The amount and type of melanin determine the colour of the hair.

In individuals with dark or pigmented hair, eumelanin, the darker form of melanin, is predominant. Eumelanin readily absorbs the laser light, converting it into heat energy that destroys the follicle. In contrast, individuals with grey or white hair have reduced levels of eumelanin and increased levels of pheomelanin, the lighter form of melanin. Pheomelanin has limited absorption capabilities, rendering it less effective at converting light energy into heat.

Alternatives to Melanin-Based Laser Hair Removal

Given the challenges associated with grey hair, researchers have explored alternative approaches to address this issue. One such method involves using longer-wavelength lasers, such as Nd:YAG lasers. These lasers can bypass melanin and instead target the blood supply of the hair follicles, causing thermal damage. While this method can provide partial results, it typically requires more treatment sessions, and the outcomes may still be inconsistent.

Colouring the Hair as a Solution?

In an attempt to overcome the limitations of laser hair removal on grey hair, some individuals consider colouring their hair before undergoing the procedure. The idea behind this approach is to introduce melanin into the hair shaft, thus increasing treatment effectiveness. However, this approach is fundamentally flawed for several reasons:

  1. Lack of Natural Melanin: Colouring the hair does not introduce natural melanin into the hair shaft. Hair dyes primarily work by depositing artificial pigments onto the hair shaft, which do not possess the same light-absorbing properties as natural melanin. Consequently, even if the hair appears darker after colouring, the laser will still struggle to effectively target the follicle due to the absence of natural melanin.
  2. Depth of Pigmentation: Laser hair removal targets the pigmentation within the hair follicle, not just the visible colour on the surface of the hair shaft. The artificial pigment in coloured hair cannot penetrate deep into the follicle to provide the necessary melanin concentration for effective laser absorption. Therefore, the lack of melanin within the follicle itself remains a significant hurdle.
  3. Regrowth of Grey Hair: It is important to note that hair grows from the root, and as the dyed hair eventually sheds, the regrowth will be grey or white once again. Since the laser’s efficacy depends on the melanin content within the follicle, the absence of melanin in grey or white hair will pose the same challenges, regardless of any temporary hair colouring.


While laser hair removal has revolutionized the field of permanent hair reduction, it presents challenges when it comes to treating grey or white hair. The absence or reduced concentration of melanin in grey hair makes it difficult for the laser to target the hair follicle effectively. Colouring the hair before the procedure does not provide a viable solution, as it does not introduce natural melanin or enable the artificial pigment to penetrate deeply into the follicle.

While advancements in technology have led to alternative options for targeting grey hair, they often require additional treatment sessions and may not provide consistent results. Individuals with grey or white hair seeking hair removal options should explore alternative methods such as electrolysis or consult with a qualified professional to determine the most suitable course of action based on their specific needs.

Posts created 69

Related Posts

Begin typing your search term above and press enter to search. Press ESC to cancel.

Back To Top