The science behind IPL hair removal

Intense Pulsed Light aka IPL hair removal is an increasingly popular method of DIY hair removal. Several friends of mine swear by it, so I was wondering how it actually works, and if it really is as effective as they say it is?

An at home IPL machine
An at home IPL machine

How it works?

IPL is light at a wavelength of 590-1200nm, which includes all visible light colours and also some infrared light. This is shown in the diagram below. These particular wavelengths of light means it can be absorbed by the hair follicles in the skin, damaging them. This process is called selective thermophotolysis. Other laser hair removal is different as it only uses one wavelength of light at a time (one colour), whereas IPL can use loads of different wavelengths at the same time. Being able to use a range of light wavelengths in IPL allows it to be absorbed by different layers of skin, so it can penetrate deeper into the skin without damaging the melanin in darker skin.

The wavelengths in IPL hair removal are circled in this diagram.
The wavelengths in IPL hair removal are circled in this diagram.

How effective is it?

Several clinical trials have found IPL hair removal to be very effective, with one trial noting a staggering 95% of users having significant hair count reduction.  However, because it works by selective thermophotolysis, it is selective in which skin and hair types it works best on. Melanin is the main protein that absorbs the IPL wavelengths, and lighter hair, grey hair and red hair doesn’t contain much melanin, which explains why IPL doesn’t really work for these people (unlucky blondies!) For people with darker hair, and those with a big contrast between their skin colour and hair colour (lighter skin with dark hair, like me!) will find that IPL works really well for them.

Don’t use IPL over tattooed skin though, when the melanin absorbs the light it heats up, and this has been reported to cause second degree burns on tattooed skin, ouch!


Better than laser hair removal?

Research concludes that diode laser hair removal is slightly more effective, but it is more painful than IPL (which doesn’t really hurt!) They are both effective though, and are both safe to use. Personally I would prefer to try IPL, as it can be done at home and I can’t be dealing with the pain of lasers!

Other uses of IPL?

It’s not just hair removal that IPL is useful for, the wavelengths in IPL can be absorbed by blood vessels, which means it can treat vascular lesions such as angiomas (common red skin growths). It is also used to treat spider veins and sun spots/age spots.

So, the hype around IPL is founded on real research, and can be explained by physics, which also explains why it is discriminatory against blondes and gingers.

Till next time,




2 thoughts on “The science behind IPL hair removal

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