Page 81 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
treatments. Tell them that they are looking at a combination of new hair and some re-growing hair, and explain why...
Treatment Timings
There appears to be much confusion in the world regarding the optimum times to treat hairs! Given that there is quite a range of anagen and telogen phase durations, it is actually very tricky to figure this out using intuition alone.
So, we constructed a mathematical model to try and figure out the ‘best’ times.
What are the optimum hair removal intervals?
Laser/IPL hair removal has been around, commercially, since the late 1990s. Many clinical studies have been carried out around the word looking at the optimum wavelength(s). fluences, pulsewidths etc. However, very little work has been done on the ‘best intervals between repeat sessions. As a direct consequence, the industry has adopted a rather haphazard approach to guestimating these intervals.
Many laser/IPL operators are trained to leave 4 or 6 or 8 or ‘whatever’ weeks between sessions, with virtually no explanation as to why!
So, we put together a computer model to investigate this more thoroughly, using data that we do know.
Clinical studies in the 1960s and 70s investigated the growth rates of hair across the body in youngish, healthy individuals with no underlying medical issues. Table 14 shows what they found (Richards & Merhag).
All hair goes through the standard anagen-catagen-telogen growth cycle. In most cases, the catagen phase lasts for around two to four weeks. So, the data above gives us a good idea of the rate at which hair grows and the percentages of hair in the anagen or telogen phase.
We constructed a model in Microsoft Excel which describes these growth patterns over a year.
Here is our blog post on this model, explaining how it works in more detail.
________________________________________________________________________ 81 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
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