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,




Using Cheerleading to get people interested in science!

Did you know, many NFL cheerleaders are also scientists?

New England Patriots cheerleader Kelly is pursuing a PhD in neuroscience! Photo credit:
New England Patriots cheerleader Kelly is pursuing a PhD in neuroscience! Photo credit:

Those who know me will know that I LOVE cheerleading, as well as science, which is why headlines about NFL cheerleaders doing PhDs and ‘The Science Cheerleaders’ program have caught my attention. Founded by Darlene Cavalier (ex 76’ers cheerleader), The Science Cheerleader ( aims to use cheer to get young girls interested in science and challenge the stereotype of both scientists and cheerleaders. I was lucky enough to get an interview with Darlene and I am excited to share it with you!

Darlene cheering for the Philadelphia 76ers
Darlene cheering for the Philadelphia 76ers. Photo credit

Thank you so much Darlene for chatting to me, I am so excited to have you here!

Why don’t you start by telling us what the Science Cheerleader is all about and what gave you the idea for the Science Cheerleader?

We enlisted the help of professional cheerleaders to recruit people for an adult science literacy campaign several years ago. That caught the eye of the media and, as a result, we started hearing from real science cheerleaders (professional cheerleaders pursuing science careers). We interviewed them online to learn more about them and share their stories. Then, in 2010, the Burroughs Wellcome Fund gave us a grant to bring 11 of them together to participate in the USA Science and Engineering Festival in Washington, D.C. They performed routines to science-themed songs, led science cheers with a LOT of young girls, talked about their careers and signed autographs/posed for pictures.  
How would you describe the current stereotype of scientists?
I, personally, don’t have a particular stereotype of scientists but we know that kids do. 
Here’s something I copied from the National Science Foundation’s website:
 A recent study of fourth graders showed that 66 percent of girls and 68 percent of boys reported liking science. But something else starts happening in elementary school. By second grade, when students (both boys and girls) are asked to draw a scientist, most portray a white male in a lab coat. The drawings generally show an isolated person with a beaker or test tube. Any woman scientist they draw looks severe and not very happy. The persistence of the stereotypes start to turn girls off, and by eighth grade, boys are twice as interested in STEM careers as girls are.
The science cheerleaders certainly challenge those stereotypes! 
As a bonus, we are also able to challenge conventional thinking about what it means to be a cheerleaders. There are an estimated 3 million young cheerleaders in the United States. Empowering them by showing them current and former cheerleaders who’ve made science and engineering their career, is powerful. Reminding them that the same skills that make them a good cheerleader will make them a great scientist and engineer, is important (time management skills, public speaking, confidence, team-building, optimism, determination, persistence, etc).
 What do you think is the most effective way to encourage young girls to pursue science?
I think it’s important to try to connect to them where they. Not just geographically where they are (which is also important) but where they are in life (what are their current interests? how are they receiving messages?). And approaching outreach with the understanding that most young kids don’t quite know what they want to be when they get older. We try to engage them in doing science through projects on SciStarter so they can see that science *is* for everyone (scientists, cheerleaders, parents, everyone).

What is the most exciting thing you have done with Science Cheerleader?

SpaceMicrobes, Guinness World Record, and our forth-coming Science of Cheerleading ebook (free). 

Where would you love to take Science Cheerleader in the future?

Global (now that I know you exist!). And we’re going to seek financial support to expand and sustain the organization and related activities.  
To find out more visit and if you are a UK cheerleader in a science career and want to get involved, drop me an email 🙂
Till next time,

World Cancer Day – and some common cancer myths

So today is World Cancer Day, where people all around the world are uniting against cancer.

Wearing our CRUK unity bands at the ICR clinical trials unit today.
Wearing our CRUK unity bands at the ICR clinical trials unit today.

It seems everyday there is a new ‘thing that gives you cancer’ in the news, and this can make many peoples view of cancer and its risks really clouded, so I thought this would be a good opportunity to share some common myths about cancer. Lets sift out the breakthroughs from the BS.

The myths:

1. Under-wired bras give you cancerin fact there is no real scientific evidence for any connection between any underwear and breast cancer risk.

2. Sweeteners give you cancermany people think ‘proper coca cola makes you fat, but diet coke gives you cancer because of the sweeteners’. This is a lie. Research has been done on the link between sweeteners like aspartame and sucralose and no connection has been found with these sweeteners and cancer incidence.  

3. We already know a miracle cure for all cancers – although all of us would love this to be true, it sadly isn’t. Cancer is a huge umbrella term including many different diseases, all needing different treatments, so there is no one ‘miracle’ treatment that will work for all types of cancer. There is also a conspiracy theory that pharmaceutical companies already know a miracle cure for cancer,and are keeping it secret to make money. This is a big fat lie, and makes no sense at all.

4. Mobile phones cause cancerThere is no evidence that mobile phone use is linked to cancer. The radio-frequency that mobile phones release does not cause DNA damage or enhance the effect of carcinogens – so as far as we know, this link is a myth!

5. Smaller breasts have less risk of getting cancer There is no link between breast size and cancer risk. Larger breasts can be a bit more difficult to examine, but although they can be a handful (pun intended) they can still be examined with a slightly different technique.

6. Cancer was created by 20th/21st century lifestylesAlthough lifestyle factors (poor diet, smoking, sedentary lifestyle) in modern days have affected cancer incidences, cancer has been around for a very long time. Even ancient Greek and Egyptian skeletons that are over 3000 years old have shown evidence of cancer! 

7. Herbal products can cure cancer – Although some herbal remedies can help with the side effects of cancer treatments, there is no evidence for herbal remedies stopping cancer spread and growth.

8. Deodorant gives you breast cancer Studies have looked into this and no link has been found, (so there is no excuse to stink!).

9. Breast implants increase breast cancer risk – This link has not been found, although implants can make mammograms harder to read, so you might next some extra scans/x-rays to check your breasts, but the risk factor for getting breast cancer is the same!

10. Sharks don’t get cancer – This myth led to some people capturing and killing sharks to study them and see why they didn’t get cancer. This is not true, poor sharks 😦

It is true however that we have made huge progress in cancer treatments for so many types of cancer, and as many people that die from cancer now survive cancer. So today on #WorldCancerDay text UNITE to 70200 to give £3 to Cancer Research UK, who fund research that is defeating cancer.

Till next time,



The science behind lip plumpers

It’s funny, we worry about being stung by a bee, but it seems we totally love the post sting look on our lips. A study has shown that the more plump women’s lips were, the younger their age was guessed as! This makes it no surprise that so many of us use lip plumpers to achieve that ‘just kicked in the mouth’ look. But how do they actually work? I looked into the science behind the pout

Lips like Angelina Jolie please?!?
Lips like Angelina Jolie please?!?
  • Irritation – When our skin is irritated by something it can swell up, and this is the basis behind many lip plumpers. They cause irritation of the delicate skin on the lips, which causes blood vessels in the lips to dilate, so more blood and tissue fluid flows to lips and they swell, giving you the daffy duck look. Ingredients that can annoy our lips so they puff up nicely include ginger, menthol, niacin and even chemicals such as capsacin which is found in chilli peppers! No wonder lip plumpers can often feel weird when we apply them! This also might explain why some women find that eating spicy food puffs up their lips just as well as a fancy lip plumper.
  •  They reflect light– A more simple way that lip plumpers work is by reflecting the light, giving the visual illusion of fuller lips. They contain ingredients that reflect light well such as glitter or mica (a silicate mineral present in many make-up products including mascara and foundation). 
  • They can increase collagen and elastin production – recently some more expensive lip plumping products claim to have a lasting effect, by increasing the amount of collagen and elastin fibres produced in your lips. They claim to do this using special oligopeptides, but to be honest I’m not that convinced on the effectiveness of this.
  • Or you could just use a shot glass… a more simple solution could be to place a shot glass over your lips and suck. Sounds weird, but it creates a vacuum seal and physically draws fluid to your lips, making them swollen. It has been found to work, but it can bruise your upper lip and give you a weird line around your mouth, so it isn’t the best idea!

So there we have it, lip plumpers give us a perfect pout mainly from irritating us, so don’t over use them as lips can get too irritated and start to peel!

Till next time,