Wednesday, 10 August 2011

SPF, sun and sea - Facts you need to know!

So here I am took a while, I know, but I had to do my reasearch! Plus, I'm on holiday so I'm finally enjoying some sun and sea!

Which brings me to the subject of my post: protecting your skin from the sun. We all know it's super important, but there are a lot of things that I personally didn't know, so I thought I'd share my recently acquired knowledge.

What is SPF?

The SPF value basically states the amount of UV that your skin absorbs. SPF 15 means that your skin will absorb 1/15th (about 6.7) of what it would absorb if no sunscreen were used. SPF 30 means 1/30th (about 3.3%) and so on . In percentage values, this means that SPF 15 will offer a 93.3% UV protection, whereas SPF 30 is 96.6% UV protection and SPF 50 is 98% UV protection.

Some studies show that SPF 15 is the best protection you can actually get. I'm obviously not an expert and can't verify these studies, so I will simply report them as I can't say I agree or disagree with them. Apparently, once you go higher than SPF 15, the marginal benefit decreases. This means that for SPF 30, you only get about 3.3% increase in UV protection with the added "bonus" of double the synthetic chemical UV absorbers in the formula, which elevate your risk of potential health problems and side effects. So the higher the protection, the higher the quantity of synthetic chemical UV absorbers.

The thing is, most people don't wear enough sunscreen. SPF 15 is good if you actually wear a LOT of sunscreen. I (and many dermatologists) feel that a higher protection is safer.

Personally, I prefer using SPF 50 the first few days I go to the beach, then SPF 30. I don't usually go lower than 30 and still tan a lot (I have dark skin to start off with). I never burn but I still think it's important to fully protect your skin!

How to choose your sunscreen!

Most agree that SPF 15 is sufficient during fall, winter and spring. My favourite brand for sunscreen in general is Lancome but there are so many good ones out there so it's really easy to find one that fits your budget AND your all-beauty-things-loving self. Personally, I don't bother buying a different sunscreen for my face and body. I don't break out easily and I don't feel I need a different sunscreen. On top of that, the chemical composition for facial sunscreen and body sunscreen is almost identical...check the INCI (International Nomenclature of Cosmetic Ingredients, usually on the back/box/bottom of the product) if you don't believe me! Cosmetic industries obviously want you to believe that  you need everything they come up with but the truth don't! Facial sunscreen is also much more expensive: for example,the Lancome "DNA guard" body sunscreen is priced at 29 € for 150 ml whereas the facial version is at 29 € for only 50 ml.

The reason as to why I'm reluctant to review moisturizer, creams and similar items is because the INCI is extremely important for me. However, I'm not a chemistry student so I can't be certain about some ingredients. I do try to learn as much as possible though, so if you're curious about a certain cream all you have to do is send me the INCI and I will do my best to analyze it.

Filters in sunscreen (chemicals which block UVA and UVB rays) can be of two types: chemical and physical. Physical filters are stable and protect your skin from the sun by deflecting or blocking the sun's rays. Chemical filters protect skin by absorbing radiation and then dissipating it safely. They can be more problematic and the unstable ones must be left on the shelf where they belong!

Chemical filters are absorbed by the skin and then secreted through urine whereas physical filters stay on the surface. For this reason, it is better to use sunscreen with physical filters on children under five and pregnant women. Physical filters are safe and FDA approved; they don't cause free radicals but are usually very pasty and hard to apply and also don't protect from the full spectrum of UVA rays. How much protection is offered depends on the particle size of the UV filters and overall product formulation. Chemical filters, on the other hand, are usually runny and much easier to apply. They are generally safe and offer more coverage against UVA and UVB rays than physical sunscreens; however, some chemical filters generate free radicals which can make your skin age. Many chemical UV filters have not been FDA approved in the States, but are in sunscreens sold in Europe and Asia. Bear in mind that chemical filters tend to be more irritating and can cause allergic reactions.

Physical filters:

  • Titanium dioxide (TiO2) - This can be comedogenic for some people. If you break out with mineral makeup as well it's probably because of Titanium dioxide.

  • Zinc oxide (ZnO)

Stable chemical filters:

  • Octocrylene : UVB filter

  • Mexoryl:
    - Terephthalylidene Dicamphor Sulfonic Ac= Mexoryl SX -  UVA filter
    - Drometrizole Trisiloxane= Mexoryl XL -  UVB filter

  • Tinosorb:
    - Bis-Ethylhexyloxyphenyl Triazine = Tinosorb S: UVA and UVB filter
    - Methyilene Bis-Benzotriazolyl Tetramethylbuthylphenol = Tinosorb M - UVA and UVB filter

  • Diethylhexyl Butamido Triazone: UVA filter

  • Ethylhexyl Triazone: UVB filter

  • Octyl methoxycinnamate = ethylhexyl methoxycinnamate: UVB filter. If this is found by itself it's stable, together with avobenzone it's not.

Unstable chemical filters:

  • Butyl Methoxydibenzoylmethane (otherwise known as AVOBENZONE): Generally unstable; it becomes stable if combined with octocrylene and/or mexoryl, tinosorb, diethylhexyl syringylidene malonate, diethylhexyl 2,6-naphthalate

  • Ethylhexyl Salycilate: Unstable, becomes stable in combination with ethylhexyl triazone, tinosorb M or S, octocrylene, or mexoryl.

Problematic chemical filters:

The following are possibly toxic and are under observation for possible interactions with estrogen activity.

  •  4-Methylbenzyliden Camphor (4-MBC)

  • Octyldimethyl-PABA (OD-PABA) 

  • Benzophenone-3(Bp-3)

  • Homosalate (HMS) 

  • Octyl-Methoxycinnamate (OMC)

This is probably a bit confusing but it's really important in order to find your Holy Grail sunscreen. Here are a few more tips...

  • Don't buy sunscreen with oxybenzone(=benzophenone-3) which generates free radicals which cause aging.

  • ALWAYS wash your face before you go to bed. Sunscreen must be removed, just like makeup.

  • Reapply every two or three hours and use generous quantities.

Make up with SPF

Now, this is a controversial subject. Some dermatologists say it's useful, some say it isn't, ALL say that it should never ever be used in place of sunblock. The general opinion is that make up with SPF is ok for incidental exposure to the sun. So when you're strolling (or desperately running and praying you won't be late, as is usually my case) round the city, going to work, to university, wherever, makeup with SPF can be quite good. But if you plan on staying in the sun for more than 15 minutes, a good SPF protection is recommended.

To be honest, I think makeup with SPF is pretty pointless. Think about how much sunscreen you need to protect your face fully. Can you imagine slathering that much foundation on? Because I really can't! The key to good sun protection is to reapply in generous quantities and frankly, if I were to do that with foundation, I would look absolutely horrific.

The quantity of makeup worn during the day is simply not enough to protect you from UVA and UVB rays. An SPF of 30 can become SPF 3 if not applied properly. So I don't use makeup with SPF usually because I find it unnecessary to put my skin into contact with filters which don't do what they promise. In any case, when buying makeup with SPF, it is best to keep in mind that the SPF indicated on the product is in reality much lower.

And so my chemistry lesson is finally over! I hope this wasn't too confusing and best wishes on finding your ideal sunscreen!


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