04 June 2006

Being Sun Wise

Supposedly, “sunscreens were originally developed by Navy researchers seeking to create a product that would allow sailors to remain on duty longer.”  While it makes for a good story, there seems to be little backing to it.  However, being of a rather pale lot, as is the rest of my home squadron, we are all very interested in the most effective sunscreen now available.  Being a nuke and an engineer, I researched.  So, for those of you who might find this useful (which should be everyone for reasons of health), I present what I have dug up, just in time for summer:

As you may or may not know, the sun damages us with ultraviolet radiation.  The UV rays are broken down into three categories, based on wavelength:  UVA (320nm – 400nm), UVB (290nm – 320nm), and UVC (200nm – 290nm).  UVC, with its short wavelength and higher energy, is very deadly.  Luckily, it is blocked by atmospheric ozone, so we don’t have to worry about it.  Sunburn is caused by UVB, so that is what most sunscreen was developed to block.  SPF is based on the UVB blocking ability of sunscreen.

However, recent research has shown that UVA is much more dangerous than we gave it credit for.  With its longer wavelength, it penetrates the outer layer of our skin and can damage deeper tissue.  It is also 90-95% of the UV radiation that reaches us.  It is thought that it is a major player in the development of melanoma, the most deadly form of skin cancer.  As this is still relatively new knowledge, not many sunscreens are effective at protecting us from UVA.

There are two primary ways to protect us from UVA, with organic chemical blockers or physical inorganic blockers.

Organic Chemical Protection:
Chemical sunscreens work by providing a larger cross-section of absorption, thus preferentially absorbing UV radiation and thus keeping our skin from absorbing it (ha, and you nukes thought that knowledge wouldn’t be applicable to real life!).

Parsol 1789 – This widely available compound is found in many sunscreens, both from well-known manufacturers and as an off-brand.  It is a decent UVA blocker, although in longer UVA wavelengths it is not as effective, and it is not overly stable, and can break down too quickly once exposed to UV radiation to provide the necessary UVA protection needed.  It also possibly has some ill-effects in some individuals.  Under certain circumstances, it might not be helpful.  Some could be allergic to it.  As it is solely for blocking UVA, it is always paired with a UVB blocker as well.

Mexoryl - Stabilized version of Parsol 1789.  It is only available outside of the US, and only from L’Oreal, who holds the patent.  You can get in on-line, however.  Research provided to the NIH says it is safe, and it works, as advertised, mice testing indicates it is safe and effective, and reduces dimers, even if FDA is not yet ready to approve it (which is why it is only available outside the US).

Helioplex – Also a stabilized version of Parsol 1789, available in the US.  It should have similar properties to Mexoryl.

An important note is that, as all of the above products are chemical blockers, they have to be applied at least 30 minutes prior to sun exposure so that they are properly absorbed by the skin.

Inorganic Blockers:
Inorganic blockers, instead of absorbing UV radiation, reflect it, so that it never reaches our skin to damage it.  There are two primary compounds used as blockers, zinc oxide and titanium dioxide.  Now, when you hear zinc, if you think the big colored stripes folks used to put on themselves from back in the 80’s, you aren’t far off.  It used to be, in order for there to be enough zinc to be an effective reflector, the sunscreen would end up being opaque.  However, advances in producing smaller particles of zinc have changed that.  Additionally, since these inorganics are reflectors, they protect against the whole spectrum of UV radiation.

Z-Cote – The brand name for an inorganic blocker, micronized zinc oxide.  It can be expensive.  Research provided to the NIH backs it as broad spectrum blocker, though.

There are other micronized Zinc Oxide brands, however, they just require a little more hunting – for example, Blue Lizard, which has zinc and titanium in high percentages; really anything with mirconized zinc oxide > 6% is good, but 8-10% is preferred.  The micronized zinc is usually, but not always, called Z-Cote as well.

Another benefit of the inorganic blockers is that since they do not need to be absorbed, you need only apply them to dry skin, no prior to sun-exposure time limit.

Conclusion:
So what will we be using?  There is no clear-cut winner, so here is my answer with the reasoning behind it:
All of us have fairly sensitive skin, as well as being obscenely pale, and with rambunctious kids getting them gooped up 30 minutes before they run out the door is often difficult.  So, we will be buying the Blue Lizard in the one gallon option.  It has very few potentially problematic organics in it, it gives great broad spectrum protection, and quite good water resistance and overall durability.  
However, it does have the texture of sunscreen – something that some folks would rather avoid.  If this is true for you, I would encourage you to consider the Neutrogena with Helioplex.  It should feel like moisturizer rather than sunscreen, and should also provide quite good UVA and UVB protection.


Oh by the way:
While doing my sunscreen research, I found Heliocare – it is a dietary supplement in daily pill form that may help boost the skin’s resistance to UV radiation.  Independent studies available on their website seem to indicate it is helpful, but to what degree I am not sure.  I will probably continue to look into this, as I am terrible about remembering to slather myself with sunscreen, but I could just take this with my daily multivitamin.

3 Comments:

At 5/10/2007, Anonymous Lee said...

Hello, I've recently become very concerned about sunscreen safety after years of religious use. So I've found your post very helpful in allaying my concerns about physical blocks. But I still have serious concerns over many of the chemical screens. Since (it seems), all of the zinc oxide suncreen products also contain chemical sunscreens, have you been able to find any products that you consider to contain a safe mix of physical and chemical sunscreens? My sunscreens' contain zinc oxide (good), mexoryl (good), but also Parsol 1789, which I'd rather avoid.
Would appreciate your thoughts on this.

 
At 5/13/2007, Blogger Pig Boat said...

Wow, back to the archives, but it is that time of year to start worrying about it, eh?

I understand your desire to avoid chemical blocks. I have similar worries. That is why I have been sticking to the Blue Lizard products, specifically the Blue Lizard sensitive skin and Blue Lizard Baby versions of their sunscreen. They are physical blocks only, no chemical. You can check the contents of their products here.

I realize I sound like a commercial, but I really do love their products. After doing the research above last year, we bought a gallon sized Blue Lizard Baby sunscreen for the family, and, frankly, we loved it. No sunburns, it stays on for about forever it seems, and no worries about chemical blocks. The only supplement we used to it was a zinc oxide sunscreen stick that we used on foreheads, because if the Blue Lizard got into our eyes it stung something awful, and the stick seemed to stay on longer (but, on the downside, we had to reapply it more often).

So I would heartily recommend Blue Lizard. You can get their stuff at most drugstores, or, if you want the gallon size, like we did, there are several places online to get it.

Enjoy the summer!

 
At 1/23/2010, Anonymous Anonymous said...

Nice blog as for me. It would be great to read something more concerning that topic. The only thing I would like to see here is a few pics of any gizmos.
Kate Watcerson
Block phone

 

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