Laser hair removal works by using lasers to emit light pulses at a particular wavelength that is absorbed by the pigment (melanin) in the hair follicle. The light energy is absorbed by the follicle, which causes it to heat up, and results in the follicle being damaged. Eventually, the hair attached to the follicle falls out, and the damaged follicle does not grow new hair.
Although laser hair removal is often promoted as giving permanent results, the truth is somewhat more complicated. This blog post explains why.
Phases of Hair Growth
All individual human hairs go through a growth cycle with four distinct phases: Anagen, Catagen, Telogen, and Exogen. The Anagen phase is when hair follicles create new hair shafts, and the hair shafts grow longer. The Catagen phase corresponds to a period when hair growth slows down, and the hair follicle shrinks. The Telogen phase is a resting state, during which old hair remains connected to the follicle, while new hair begins to grow underneath. The final Exogen phase occurs when old hair shafts fall out, and new hair continues to grow.
The four phases also take very different periods of time: Anagen can last anywhere between two and seven years. Catagen lasts up to two to three weeks. Telogen takes between three and four months. Exogen is harder to define; it actually overlaps with the other phases.
Effectiveness of Laser Hair Removal
Laser hair removal procedures are most effective during the Anagen phase, while the hair follicle is growing a new hair stalk, and the hair follicle contains the most melanin. The laser is tuned to a frequency that is absorbed by the melanin, which results in the light energy being efficiently converted to heat. This heat damages or kills the follicle, inhibiting future hair growth.
The following factors combine to prevent single laser hair removal treatments from being able to remove all hair in the treated area:
- the hair growth cycle results in not all hair is in the Anagen phase at any given time.
- individuals vary greatly in the lengths of their hair growth cycles, influenced by hormonal and genetic factors.
- hair thickness also varies greatly between individuals, which may influence how effective the laser is at damaging hair follicles.
- the period during which hair does not grow is influenced by many factors, including age.
- the damage caused by the laser heating up individual follicles may not be enough to completely prevent new hair growth. Partial damage can result in the regrowth of lighter, finer hairs.
- the laser equipment being used may not be a perfect match for the patient’s hair and skin colors.
- the practitioner’s skill may also influence how effectively hair removal occurs.
Permanent or Temporary?
Given that a single laser hair removal treatment will not be 100% effective, in most cases patients will be advised to have several treatments, spaced out appropriately. This technique will certainly increase the percentage of hairs removed in the treated area, over time.
The various factors that influence the effectiveness of laser hair removal combine to make it quite unlikely that even a skilled practitioner will be able to achieve permanent 100% removal of hair in a given area after just a few treatments. In some of the real-world cases, further treatments will be needed to maintain the results, although the intervals between these treatments will generally become longer over time.
Your Laser Skin Care
Your Laser Skin Care practitioners are medically qualified and highly experienced in performing laser hair removal. We also have extensive experience with a wide variety of other non-invasive cosmetic procedures. We can help you choose the safest, most effective, and most cost-effective way to achieve your cosmetic goals. Call us at (323) 525-1516 to schedule a free consultation, or visit us online for more information.