Rebecca requests…On a recent trip to the beach I was unfortunate enough to sit down wind of someone applying a spray on sunscreen. I think less than half of what she sprayed actually hit her body because most of it was blown away by the breeze and landed on me! I could feel it and even see a fine film covering my sunglasses. I couldn’t help but wonder how in the world a spray on product can provide effective sun protection. Do the spray products use different ingredients than the lotions?
The Left Brain responds:
Formulating a spray-on sunscreen does present different challenges than creating a lotion product.
Spray-on savvy
To start with, even thin emulsions are difficult to spray because they don’t atomize well and they can clog the valve. So, most spray products are solutions of UV absorbers in ethanol. That means only alcohol soluble ingredients like Avobenzone, Homosalate, Octisalate, Octocrylene, and Oxybenzone can be used. Physical sunblocks, like titanium dioxide and zinc oxide, are not alcohol soluble so they can’t be sprayed from this type of product. In addition, to help ensure that the sunscreen coats the skin evenly, film forming ingredients like Acrylates/Octylacrylamide Copolymer are added. These film formers helps keep prevent the alcohol solution from pooling in nooks and crannies of your skin.
Of course none of this matters if too much overspray occurs. If the spray doesn’t hit your skin it’s obviously wasted. While they are appealing because of ease of application you may be getting less deposition than you realize, especially if you’re applying them on a windy day. Considering how important uniform sunscreen application is for the prevention of sunburn (and potentially skin cancer), I think it’s a bit risky to rely on this kind of spray application.
Perhaps that’s why sprays are not “officially” approved as sunscreens even though they are sold as such. According to an article by Stanley B Levy, MD published Medscape, as of April 11, 2012, “The FDA Final Monograph has not approved sprays as a dosage form pending further considerations and testing.”
Spray-on= $$
Furthermore, all that wasted over spray makes spray-on sunscreens potentially more expensive to use. And when you factor in the cost of ethanol (which is a more expensive solvent than water) and the aluminum can and the valve hardware (which are more expensive than a plastic lotion bottle), you may end up paying a lot more for the convenience of not getting lotion all over your hands. I think I’ll stick with lotions.
Image credit: seemsartless.com
References:
Chemist’s Corner: What’s in a sunscreen and why?
{ 8 comments… read them below or add one }
I’ll point out as well that there are recommendations not to use spray sunscreens on children, since they tend to be inhaled. I can’t imagine it’s a good idea for grownups to inhale them, either…
I find that lotions tend to make my already-oily skin feel even greasier, so I prefer sprays. I recently found that Banana Boat is making sprays that contain NO water and one of them (the kids tear-free, I believe) contains titanium dioxide. Can you address how such sprays would work as compared with the more conventional sprays discussed in your post and in the Chemists Corner article? Also, do the BB spf100 sprays provide better UVA protection than their spf 30 sprays? (They both contain the same percentage of avobenzone) Thanks!
@Scientist: The Banana Boat product is an interesting one. Looks like they are using an emulsion base (not an alcohol solution) which is how they get to their tear free claim. I don’t know how this will work compared to “conventional” sprays, but in regards to the TiO2 it looks like that added as a non-functional ingredient, not as a physical sunblock. It could be there to help give the product it’s white appearance that’s one of the product features (so moms can see where the product has been applied.)
Thanks for your response. I meant to say the Banana Boat contains no alcohol, not no water! Please edit my original post to reflect that. (no need to publish this one)!
I totally agree with you. Spraying sunscreen will always be more expensive than using lotion bottles. Not only because of the hardware as they are producing plastic version instead of using aluminum, the spraying cannot be controlled. You may end up spraying on other areas instead of all of it to your body. And yes, when it is sprayed, it can be inhaled. Applying it directly to your skin is more practical. Cheers!
I usually just spray into the palm of my hand, and take it from there. Easier to get the right amount.
same here, i spray in my palm first as well. i use spray as i like the non greasy formula better. i like loreal one and UVA protection is great with the mexoryl
Great tips!
Well, I also don’t trust spray on sunscreens.
When you spray it on, some will just be wasted since it will just drop off to the ground , so I think its not really a good deals for sunscreen.
Elena
My blog : papier peint New York
{ 2 trackbacks }