How does a sunscreen work?

I asked a question in my last post and that was because of a reason. Recently, I visited a well known parlour in Sector-18, NOIDA. I was getting my clean-up done; in the meanwhile, a lady asked about the best sunscreens and how to apply them. The head of the parlour said you should always apply your sunscreen under your moisturizer. I contradicted by saying that neither (sunscreen and moisturizer) would do their job and it should be done the other way round. Frankly speaking, I had no idea but I used my logical mind because of the studies I had done during my preparation for Medical Exams. But she went on and on about how she has graduated from so and so college abroad, whatever she know is correct etc. One more fact, it's the second time when I got this suggestion by the parlour. But I didn't give this discussion a piece of my anxious mind that time because I hardly cared.

Talking about the recent discussion; yes, I admit my knowledge stumbled a bit because of her position in that parlour, plus knowing her graduation degrees etc I was forced to give it an evening full of questions if she was right or my logic was right. I am glad that you all answered how I thought it to be. It also forced me to do a search on sunscreens and how they work.

How does a sunscreen work!?!

A sunscreen product acts like a very thin bulletproof vest, stopping the Ultraviolet (UV) photons before they can reach the skin and inflict damage. It contains organic sunscreen molecules that absorb UV and inorganic pigments that absorb, scatter and reflect UV. To deliver a high level of protection, a sunscreen product must have sufficient quantities of these protective agents and it must optimally deploy them over the skin's peaks and valleys.

The term SPF that appears on sunscreen labels stands for Sun Protection Factor, but it is really a sunburn protection factor. Products with a higher SPF allow fewer of the photons that produce sunburn to strike the skin. In simple terms, you can view an SPF 10 sunscreen as allowing 10 out of every 100 photons to reach the skin and an SPF 20 product as allowing only 5 out of every 100 photons to reach the skin. Because sunburn is primarily a UVB effect, it is possible for a sunscreen product to deliver high SPF while allowing a significant percentage of the incident UVA photons to reach the skin. To deliver true broad spectrum protection, products must also block a significant fraction of the UVA photons. In the U.S. market, this requires that the products contain significant levels of zinc oxide, avobenzone or titanium dioxide. read more here

A quick experiment on "how sunscreen works" :

Take a day-glow pen and draw a picture on your hand.

Put your hand underneath the UV light. What do you see?

Smear sun cream over half of the picture. on your hand and put your hand back under the UV light. What happens now?

Read here about what happens after putting sunscreen on the picture.

Most of us know how it happens. I am glad that I researched and got the logic.

Have you ever encountered wrong suggestions given by someone in parlour? What was that suggestion?

Posted in: Parlour,Question and Answer,Sunscreen,suntan