Page 237 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
Myth 4 – “The broadband wavelength range of IPLs makes them ‘much weaker’ than lasers”
Let’s begin with Myth 1 – This is partly correct – lasers are not IPLs. If you read Chapter 1 you will see that this is clearly obvious. They are quite different technologies and generate light by completely different methods.
But, the end product – the light energy – is basically the same! The main difference, which is important in terms of skin treatments, is that all of the energy in a laser output is contained within a very narrow range of wavelengths – a few nanometres (Heisenberg’s Uncertainty Principle does not allow all the energy to be emitted in a single wavelength!).
This means that we can match those wavelengths with a specific chromophore, such as haemoglobin in blood. The result of this is that much of this energy will likely be absorbed by that chromophore.
IPLs, on the other hand, output energy across a much wider range of wavelengths, typically hundreds of nanometres. While this means that the absorption is not as specific as with a laser output, it will still induce a reaction in the target chromophores.
In particular, if the target chromophore is melanin (as for hair and pigmentation) then the wide range of wavelengths is advantageous, since melanin absorbs light across the full visible spectrum (plus a bit of the near infrared too).
So, for hair removal, the fact that IPLs deliver their energy in a wide range of wavelengths is not a disadvantage, when compared with lasers!
Myth 2 - IPLs “don’t penetrate as deeply as lasers.”
We see this a lot on social media forums and posts. It displays a basic lack of knowledge of the physics. The depth of penetration of light depends on a number of factors, the main one being the ‘extinction coefficient’. This coefficient combines the total amount of absorption, forward and back-scattering that will occur in the tissues. Each tissue (collagen, blood, melanin, keratin etc) will interact differently with light.
Our YouTube video on “The difference between lasers and IPLs” (Our most popular video to date with over 20,000 views as of March 2025.)
________________________________________________________________________ 237 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
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