Friday, August 10, 2012

Are Chemical or Physical Sunscreens Better? (Part 2 of What You Should Know About Sunscreens)

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In my last sunscreen post, I explained why it’s important to use a sunscreen that protects against UVA and which sunscreen ingredients protect against UVA radiation (so head over to that blog post first if you haven't read it).

Today I'll dive into the debate on whether physical or chemical sunscreens are better (it's a real standoff!). This issue is very complicated, so forgive me that this post is long and detailed. I'll give the summary up front, and then if you are interested in more details, you can read on. :)

My personal belief is that it is better to use a physical sunscreen on a daily basis so there is no risk of chemicals absorbing into the body, accumulating in tissues, and disrupting hormones. The truth is, we just don't know what the long term effects are of using these chemicals frequently on our bodies. We DO know that some percentage of chemical sunscreen filters DO absorb into the body, and we DO know that they can disrupt hormones by mimicking estrogen. While physical sunscreens don't provide super high levels of UVA protection, they can provide stable, quite decent level of protection great for everyday wear.

That said, I think using chemical sunscreens occasionally is fine - the small percentage that will absorb into the body just won't be enough to matter. I opt for using a chemical sunscreen on days I know I'm going to get a lot of sun exposure because they (if they contain Tinosorb or Meroxyl) provide a much higher level of protection from UVA radiation that physical sunscreens.

Now let's dive into the details!

Here's the scoop on physical sunscreens:

Not all physical sunscreens are created equal. First of all, make sure your sunscreen has at least 10% zinc oxide; while titanium dioxide is also a physical filter, it does not protect against the whole UVA spectrum. So many sunscreens, such as Neutrogena Pure & Free Baby SPF 60, have very low amounts of zinc oxide and yet claim high SPF and UVA protection. Watch out for this! If you put Neutrogena's baby sunscreen info into a sunscreen calculator, you'll see that its SPF is closer to 10, not 60, and its UVA protection is abysmal! I just don't know how they get away with these claims.

Now that you've made sure your sunscreen has enough zinc oxide, it's time to make sure the kind of zinc oxide and titanium dioxide used are safe. Many sunscreens use nanoparticles of zinc oxide and titanium dioxide, which are fantasically small particles. The jury is still out, but it's possible that a percentage of the nanoparticles can absorb into the body, and we don't know the long term effects of this. Studies have also indicated that ingesting nanoparticles of zinc oxide can increase risk of colon cancer. For these reasons, I prefer to use nanoparticle-free sunscreens. Sometimes it's hard to know if the sunscreen contains nanoparticles or not - in this case, call or email the company, and they should be able to tell you. (If you see the word "micronized" that is ok - microparticles are larger than nanoparticles.)

Finally, if titanium dioxide is used in your sunscreen, make sure that it is coated. "Coated" means that each particle has a coating, such as silicone. This is important because titanium dioxide reacts a lot in sunlight and releases energy that causes free radical damage to skin. Coating the mineral reduces its photoreactivity, so you can feel more comfortable it's safe! (Zinc oxide is less photoreactive, so it is ok if it is uncoated).

The main problem I've had with non-nano, high percentage zinc oxide sunscreens is they usually leave me looking like this:

Image frome here

Others may be clear, but are sticky or drying...I'm still searching for the perfect zinc oxide sunscreen, and I know there's one out there somewhere!

Now here's the low down on chemical sunscreens:

I'll be honest, I just don't like the chemical sunscreens sold in the United States because there are hardly any sunscreens available with the latest, most stable and effective chemical sunscreen filters (Tinosorb and Meroxyl). As I mentioned in my last post, the combination of avobenzone and octocrylene (which is in most U.S. sunscreens) is stable for some time, but it is destabilized if you put makeup (foundation, powder, etc) on top of it. I also believe you should reapply it frequently given avobenzone's tendency to break down in sunlight.

Meroxyl and Tinosorb, which are much more stable, provide an unparalleled level of UVA protection. La Roche Posay's Anthelios sunscreen is the only one I know of in the U.S. that contains Meroxyl, but most of their sunscreens also contain oxybenzone, something I recommend avoiding. The European versions of this sunscreen are oxybenzone free.

I am head over heels in love with Tinosorb - it is incredibly stable in sunlight. It works by reflecting AND absorbing UVA radiation - so it works like a physical and chemical sunscreen at the same time! Even more exciting, it does not disrupt hormones like many other chemical sunscreens! I have worn a Tinosorb sunscreen outside in bright daylight for 5 hours straight, not reapplied and not even gotten a tan - it is that good! People claim they see their hyperpigmentation and freckles fade when they use a Tinosorb sunscreen regularly.

If we're talking about the level of UVA protection, then Tinosorb or Meroxyl sunscreens win hands down over physical sunscreens. The only problem is, Tinosorb and Meroxyl never appear in sunscreens without other chemcial filters as well - chemical filters that disrupt hormones - so I still prefer to not use them daily.


Level of UVA Protection (physical vs. chemical):

I'll tell you about a very interesting tool - the sunscreen calculator - you can use this to check the real SPF level and UVA protection level of your sunscrens by entering the ingredients. Here's the link:

You have to sign up, then you can log in. Be sure to set the "region" at the top to "all filters" or else it doesn't work well (I don't know why).

UVA is measured in Europe in PPDs (like an SPF but for UVA). Good physical sunscreens can give a PPD of only about 10. A Tinosorb or Meroxyl sunscreen on the other hand gives a PPD of 30 to 40, which is really superb!

Where to buy Tinosorb, Meroxyl, or nanoparticle-free zinc oxide sunscreens:
I recommend ordering your Tinosorb or Meroxyl sunscreens from sites that import from Europe or Asia. Bioderma, Avene and La Roche Posay make some good ones, but you have to be sure it's the European product, or you may not be getting the right formulation!,, or sell some of my favorites. Alternatively pick up a bunch if you travel abroad, or ask a friend or family member to if they are going abroad! I try to stockpile whenever I travel (it's much cheaper that way).

As a side note, Tinosorb and Meroxyl are sometimes listed on the ingredient list by their chemical names (Tinosorb or Meroxyl are like brand names). Just so there's no confusion, here's the list of the chemical names:

Tinosorb S: Bis-ethylhexyloxyphenol methoxyphenyl triazine; or Bemotrizinol
Tinosorb M: Methylene bis-benzotriazolyl tetramethylbutylphenol; or Bisoctrizole
Meroxyl XL: Drometrizole trisiloxane
Meroxyl SX: Terephthalylidene dicamphor sulfonic acid; or Ecamsule

To order great physical sunscreens, I recommend websites such as,,, and Some brands I've used are Burnout, Alba Botanica, Dermaquest, and Elta MD (though it contains nanoparticles). I may try SkinCeuticals (also has nano-particles), DeVita, and Renee Rouleau's zinc oxide sunscreens soon.

In the next installment of this series, I’ll share what sunscreens I’ve tried, which are my favorites, and how they rank as far as UVA protection and safety!


  1. Great post Ashley-where do you get all this information?! And I can't WAIT to read about the nano-free sunscreens! also, any news on spf lip tints that are chemical free?

  2. Hi Nadia! I still haven't found a tinted balm with mineral SPF :-(. Lavanila has one with zinc oxide, but it's not tinted. Same for Burnout. But I did not look at Burt's Bees yet. I'll let you know if I stumble upon one!

    1. Great article Ashley! I'm so much more informed about sunscreens now. You really broke it down.Should I trash my neutrogena with helioplex? Is it really bad for me even if I don't wear make up over it. What would be the best drugstore sunscreen to use?

    2. Hey Momo,
      I'd get rid of the Neutrogena and replace it with something else. I'm not sure what all brands they sell in the drugstore in NY, but here there just aren't any drugstore sunscreens that I like much. The best would be Coppertone Sensitive Skin Suncreen SPF 50 (with zinc oxide, octinoxate, octisalate) OR Coppertone Faces Sensitive Skin Sunscreen SPF 50 (again, zinc oxide, octinoxate, octisalate). Check the bottle, because they have some other versions that do not have these ingredients and have oxybenzone. The only reason I don't like this susncreen is that it contains a formaldehyde releasing preservative (Diazolidinyl Urea) that I don't like to use on a daily basis.

      If you're willing to look outside the drugstore, I'd recommend Shiseido sunscreens (in the blue bottles), Elta MD sunscreens (the ones with zinc oxide), DermaQuest Zinclear. I haven't tried it but Chanel UV Essentiel gets crazy good reviews. The only thing is the Elta MD and Shiseido (don't know about the Coppertone or Chanel, I need to contact those companies) have nanoparticles. You'll have to decide if you don't mind using a sunscreen with that in it.

      I'm working on a "Sunscreen Guide" that lists and ranks about 50 sunscreens. I think it will help you find one. I know I'm slow posting it, it just takes such a long time to compile the info.

      Oh, and here's the links to the Coppertones:

  3. Have you finished your Sunscreen Guide yet?

    1. Hi Kansaslily!
      I have gotten a good deal of work done on it, but have not been able to finish because I got not one, but two new jobs and just haven't had time for the blog the past few months :-(. However, very soon I will start posting again, and I will try to make sure that the sunscreen guide is one of the first things I post. I can let you know when I've posted it. I'll reply here to this thread, or I could email it to you, so you don't have to keep checking back here. Thanks for reading, and for your comment!


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