Page 34 - Blog Posts v1

A11 - Laser/IPL Hair Removal - How many follicles do we kill each treatment?
All hair follicles grow according to a cycle – ‘anagen, catagen, telogen’. The follicle germative cells promote anagen hair growth at consistently regular intervals resulting in periods of active growth, followed by inactivity. The duration of these periods depends on the which part of the body is being considered.
I created a computer model to investigate these growth cycles. I wanted to determine the ‘best’ intervals between laser/IPL treatment sessions to generate the best outcomes. My main criteria was that we wanted to retreat areas when the maximum number of follicles were back in anagen.
Chin Bikini
77 66 66
Table 1: Number of sessions required to kill almost all follicles across the body
In the real world, nobody can effect a 100% efficient treatment. So, we can never kill every anagen follicle when we treat. In reality, the efficiency is somewhere between 60 and 80%, in most cases. Table 1 shows the number of sessions required to kill virtually all follicles across the body when assuming a 60% efficiency, for three intervals between sessions - 4, 6 and 8 weeks. The number of sessions required doesn't change that much and these numbers are very close to what most clinics around the world achieve.
An 80% efficiency will reduce those numbers by only 1 or 2 sessions! The two ways to improve efficiency are 1: better equipment and 2: better training.
However, my model clearly shows that the first treatment will always generate the highest clearance – around 33%. Subsequent treatments kill fewer follicles, simply because there are less to treat each time.
Interval (weeks)
Upper lip
4
7
6
7
8
6
Arm pits
Legs
7
9
6
8
6
7
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