Page 12 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
Table of Contents
Section 3.1 – Overview of Hair Removal Using Light Energy 17
Hair Removal using Light Energy – in a nutshell 18
The basic parameters (settings) in lasers and IPLs 21
The Epidermis and Skin Colour 27
Melanin and its effects on hair removal (Absorption Coefficients) 28 Skin Colour and melanin concentration 29 Hair colour & skin colour – contrast – why this is so important 33 Skin Colour 6 – ‘Black’ skin 34
Hair Colour vs Skin Colour – How are they related? 34
Measurement of epidermal melanin content 35 Epidermal peak temperatures for three fluences 37
Epidermal temperature rise due to skin colour 39
Tans – Sun or sunbeds 43 Hirsutism and Hypertrichosis 44 Melanin Absorption, Skin Colour and Pain 45 What is the difference between melanocytes and melanosomes? 47
Laser / IPL Treatment of Hair – the Fundamentals in more detail 48
The Fundamental Principles of Light-based Hair Removal Treatments 48 Selective Photothermolysis and hair removal – a quick review 49 Thermal relaxation time – how important is it? 49 How do pulsewidth, thermal relaxation time and denaturation time relate? 52 Management of Safe and Efficient Light-based Skin Treatments 56 Light Absorption in Epidermal Melanin 56 Optimal Skin Cooling in Laser Hair Removal 58 Thermal Pain Sensors 61 Thermal Nerve Density across the Body 64
Laser Hair Removal – A Thermo-Chemical Process 64
Depths of the bulge and bulb in hair follicles 67 Hair depth and fluence 69 Melanin absorption – how they compare across devices? 73 Epidermal Complications 76 Dermal Complications 76 Dormant Follicles 77 Thick and thin hair – how much light energy do they absorb? 77 What does this mean for light-based hair removal treatments? 78 Skin diseases and disorders 79 What cannot be treated? 80 Proper language when talking to clients/patients 80
Treatment Timings 81
What are the optimum hair removal intervals? 81 How much hair is lost following treatments? 88 ‘Re-growth’ of hair 90 Hair treatment intervals – what is the ‘best’ time to leave between sessions? 91
Section 3.2 – Science / Biology 95
The Important Science and Biology Involved with Hair Removal 96
Basic Terms You Really Should Understand 96 Selective heating - The impact of object colour vs the colour of light 97 Fundamental optical properties of the skin 99
________________________________________________________________________ 12 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
© The Laser-IPL Guys, 2025