Applying Sunscreen: how much, When, and Where

Now that so many products contain sunscreen (foundation, concealers, moisturizers, and even face powders), the next question is, What about application? That’s a great question! The major issue for the use of any well-formulated sunscreen (SPF 15 or greater with UVA – protecting ingredients) is liberal application. Why? Because protection is determined not only by the SPF number and the UVA ingredients the product contains, but also by how thick and evenly it is applied, and when, where, and how often the sunscreen is reapplied. But studies show there is a mismatch between the expectations versus the reality of actual
use. (Sources: Lancet, August 11, 2007, pages 528-537; and Journal of Photochemistry and Photobiology, November 2001, pages 105-108.)

Research indicates sunscreen users are only applying 50% of the recommended amount, so they are only receiving 50% of the SPF protection. And that means expensive sunscreen may be dangerous to your skin’s health. After all, how likely are you to liberally apply an expensive sunscreen? Not applying sunscreen liberally can negate any benefit you may as­sume you are getting from the SPF number on the label.

You may have seen recommendations that you should apply sunscreen 20 minutes before you go outside and then again 20 minutes later or whenever you get to where you are go­ing. This is all about the issue of application. Because research has made it clear we aren’t wearing enough of the stuff, dermatologists have recommended these use options to get us to comply, and really put on enough to take great care of our skin.

Keep in mind that everyday liberal application, applied 20 minutes before you step outside (not once you get to the car, or get to the beach, or do anything—but before you leave the house) is the key element in getting the best protection possible. But within your skin-care routine, exactly when does sunscreen get applied? If you are applying several skin – care products, ranging from toners to acne medications to moisturizers, the rule is that the last item you apply during the day is your sunscreen. If you apply sunscreen and then apply, say, your moisturizer or an acne product, you could inadvertently be diluting or breaking down the effectiveness of the sunscreen you’ve just applied.

Any skin-care product, or even just water (and almost all moisturizers are more than 50% water), applied over a sunscreen reduces its effectiveness to one degree or another. This is why you have to reapply sunscreen after swimming or perspiring. If you use moisturizers, which are always lipid soluble, over your sunscreen these will break down the sunscreen via dilution or removal, and that is a serious problem. What about applying foundation (one that doesn’t contain sunscreen) over the sunscreen you’ve just applied? That depends on several more factors, such as how much you apply, how thick or oily it is, or what kind of sunscreen you are using. To eliminate any dilution and to add more protection, you can choose to wear a foundation during the day that contains sunscreen. Voila, no more worries.

If you are using more than one product containing sunscreen, such as an SPF 15 mois­turizer and an SPF 8 foundation, it is important to understand that does not add up to an SPF of 23. You would get some increased SPF protective value, but there is no way to know what amount of increased protection that would be. If you want to get the protection of SPF 30, then that is the SPF number you should look for. If you are mixing SPF products, both must contain UVA-protecting ingredients.

What if your foundation is the product you’ve chosen for sun protection? Then the trick is to be sure you’ve applied it evenly and liberally. If you apply it too thinly or blend most of it off instead of using it full-depth, you would not get the amount of protection listed on the label.

I am concerned about the pressed powders with sunscreen. Although I don’t doubt the validity of these product’s SPF ratings, I worry that most women do not apply pressed – powder foundations liberally enough to get the amount of protection stated on the label.

If you lightly dust the powder over the skin there is no way you will get the SPF protec­tion the label indicates. You must be sure you apply the pressed powder in a manner that completely and evenly covers the face. I believe that pressed powders are an iffy way to get sun protection for the face, but they are a great way to touch up your makeup during the day and reapply more sunscreen at the same time.

A few more important facts:

• Even on a cloudy day the sun’s rays are ever-present and ever attacking the skin.

• Sitting in the shade or wearing a hat protects you only from a small portion of the sun’s rays. Plus, other surrounding surfaces such as water, snow, cement, and grass reflect the rays up from the ground to your skin, giving you a double whammy of damage.

• Altitude is a sun enhancer; for every 1,000-foot increase in altitude, the sun’s potency increases by 4%.

Time of day does matter. All UV radiation is strongest between 10 A. M. and 2 P. M. Clouds filter some, but not most, of the UVR, which is why you are still likely to get burned on an overcast day, and the UVA rays are still strongly present, too.

Updated: September 13, 2015 — 3:13 am