Page 3 - Chapter 3 - Fundamentals of Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 1st Edition
This is the ‘hairy chapter’ of our book
We wrote this book after many years’ of clinical research and training (more than 50 between us and counting) people in the theory and use of medical/aesthetic lasers and IPLs across the world. Many times, we were asked for ‘a book’ to refer to by trainees. We had to keep saying – “one doesn’t exist”. There are plenty of good medical texts, but these are aimed at medical professionals. There are also a lot of good physics and engineering books – but these are useless for most laser users.
This book describes some of the basic fundamentals of light energy, lasers and IPL systems, in “layman’s” terms. We explain the jargon and some of the more important concepts, which really should be well understood before firing laser/IPL energy at real, living people (if you want them to remain alive and well, and with no hair!!)
Hair removal using light energy is a science – it doesn’t matter if it’s laser or IPL light energy. The fact is, understanding the science will increase your chances of success significantly. There is no ‘art’ or ‘intuition’ with this subject – it is purely science, which is why this book is science-heavy!
We hope you enjoy reading it.
Terms used when discussing hair
Hair Most people think of a hair as the hair shaft which sticks out of the
skin surface. However, this is only the visible part of the structure.
Growth Follicles go through a number of growth phases:
Follicle
A hair follicle is the structure which contains all constituents of the hair – it is an ‘indentation’ into the epidermis/dermis and is usually connected to a sebaceous gland and an arrector pili muscle. The follicle consists of the infundibulum, the isthmus and the bulb.
Anagen
The anagen phase is known as the proliferation phase when a new hair shaft is generated. This phase can last from a few weeks to years, on the scalp. Recent clinical research indicates that the anagen phase may consist of six distinct parts.
Catagen
The catagen phase is the ‘transition’ phase when the hair stops actively growing. The follicle effectively shrinks in size as it regresses towards the surface. It usually lasts around two to three weeks, for all follicles.
Telogen
The telogen phase is known as the resting phase, During this time the follicle is relatively inactive and the hair is effectively dead. This phase can last between a few weeks and a few months, depending on the body area.
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