Page 89 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
The table above shows us quite clearly that photothermal hair removal is a case of ‘diminishing returns’ (see Table 19). Each time the patient/client comes back for a follow-up session, they have fewer follicles available for treatment. Even fewer of those will be in the anagen phase at the time of treatment.
Take, for example, the treatment of a chin with an EKR of 60% (which appears to be fairly average). According to our results in Table 19, up to around 48% of all the follicles may be destroyed in the first session. But, only 31% might be destroyed in the second session. This then reduces to 13, 5, 2 and then finally 1% in each subsequent session. But this assumes that the correct parameters are being applied in each treatment session!
Figure 44 – The progression of hair removal during treatments.
Figure 44 shows how laser/IPL hair removal progresses. At ‘Day 0’, the area is full of hairs in all three phases – anagen, catagen and telogen. During the first treatment, some (typically between 50 and 60%) of the anagen hairs are killed (in red). But, only the anagen hair follicles are affected leaving most of the follicles untouched. In addition, some of the anagen follicles have not been fully denatured – they will grow back later with finer hairs (usually due to insufficient fluence!). A short time after the first treatment we can see that the total number of follicles has reduced. However, a few weeks later, some of those follicles have changed phase – this is important! If too short a time is left between treatment sessions, then there may not be much difference in terms of total number of anagen follicles presenting for the next treatment session.
________________________________________________________________________ 89 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
© The Laser-IPL Guys, 2025