Sunscreen And Why To Use It

I talk about skin aging a lot and one of the main causes of collagen breakdown is the sunlight. Or more to the point, ultraviolet radiation.

Ultraviolet rays are emitted by light sources, such as sun. They are invisible to the naked eye although we feel the effects of it on our skin through suntan and sunburn. 

There are a few types of UV rays, but the ones of interest in skincare are medium and long waves or UVB and UVA. For simplicity I call them "burning" and "ageing" rays, although it's not entirely correct. UV rays are also responsible for production of vitamin D in the skin.

So, the rays are there, some are absorbed by the ozone layer, but a lot get to the Earth's surface. We do need them, but we also need to protect ourselves from overexposure. UV rays can also impact the DNA structure directly and indirectly, and cause skin cancer.

So how can we protect ourselves? Obviously by using sunscreen when planning a direct exposure - sunbathing. And that's when majority of people tend to use sunscreens when they can actually see the big bright sun in the sky. But they should be using them on a daily basis.

Sunscreens can be organic chemical compounds and physical (mineral). Chemical sunscreens absorb the UV rays and physical reflect and scatter them. The thing is whatever they are made of, they will break down in a couple of hours and you'll lose your protection. And that's why when we're sunbathing, it says to reapply liberally every couple of hours or more often if we're swimming, etc.

But how about when we are out and about during the day and in a city with full make up on? That's when it gets more complicated and confusing.

Lots of us want to save time so we'll buy a moisturiser with built in SPF. Most of them if mixed into creams are chemical ones and they will rarely offer my more than UVB protection, so it means that you're still exposed to the UVA radiation. 
But the biggest problem is that the chemical sunscreens can be a bit controversial. Some can cause allergic reactions, some interfere with DNA.
So that leaves us with mineral sunscreens. They are the ones that create a barrier on skin and leave us with a whitish tinge. They are the best we can get at the moment, a broad spectrum mineral sunscreen that we apply on top of our daily moisturiser. 
The key in choosing a good one is that there isn't one. Go for the maximum protection that you can. I tend to pick SPF50 and I go for the texture and smell that I like. Many of them can be greasy so try a few. My personal favorite is Sisley Broad spectrum facial sunscreen, but it is expensive. Shiseido does a good high protection UVA/B sunscreen and, while it's not exactly a bargain, it is cheaper.
But don't forget that even the best sunscreen will break down in strong sunlight and stop giving you protection, so cover up with a hat.