New Ways To Maximize Sunscreen's Effectiveness
Why one prominent dermatologist wants you to apply sunscreen the night before sun exposure.
With increased exposure to the damaging effects of the strong summer sun, how do we go about protecting our skin in the most effective way possible? Some sun-savvy tips from co-developer of Retin A® James E. Fulton, MD, Ph.D. on how to reap the greatest benefits from our sunscreen:
Cumulative effect
Over and over, we hear that, for sunscreen to be most effective, it should be applied at least an hour before sun exposure in order to permit its ingredients to fully activate, and then reapplied every couple of hours during exposure. Dr. Fulton takes this advice a step further.
Because, by consistently using sunscreen, one builds up a reservoir of protection in the epidermal level of the skin (the stratum corneum). Dr. Fulton recommends applying sunscreen the night before exposure to sun, followed by a second application an hour before exposure, preferably while skin is moist. In fact, if Dr. Fulton has a patient who is going to the beach on Saturday, he'll often have them apply sunscreen on Thursday night, Friday night, and then again on Saturday morning to build up an optimal layer of protective sunscreen in the stratum corneum. Once this protective reservoir is built up, it takes approximately three days for it to dissipate, so if the patient forgets to reapply sunscreen once during the day of exposure, the consequences aren't dramatic.
Apply while skin is freshly hydrated
As with all skin treatments, sunscreen¹s active ingredients penetrate the skin more readily when applied immediately following a bath or a shower, when skin is still moist. This same principle applies to subsequent applications throughout the day. Reapply when skin is still damp from swimming. And remember, even waterproof sunscreen claiming to last throughout the day requires frequent re-application, because waterproof doesn't necessarily mean "towel-proof"
Alcohol vs. cream based sunscreen. Sunscreens with an alcohol base provide longer lasting waterproof protection. Why? The alcohol base provides a more effective "delivery vehicle" for the sunscreen's active ingredients because, when the alcohol evaporates off the skin, the heat of the evaporation helps the ingredients penetrate the skin and bind to its top layer. This results in a more effective barrier to the sun¹s damaging rays, with notably more staying power.
Quantity counts
Most people do not use enough sunscreen. For all-over body protection, anything less than 1 oz. (a shot glass-full) won't do it, and will lessen the effectiveness of a high SPF. The average 8 oz. bottle of sunscreen contains no more than 8-10 applications. Does this mean greater expense at the pharmacy? Yes and, it's well worth it.
Regarding SPFs (sun protection factors), most people think that high SPF numbers will double or triple the more common SPF 15 sunscreen¹s protection. Research has shown that 95% of the skin cancer causing rays are blocked with a SPF 15 sunscreen. A SPF 50 blocks about 97% of these rays. Therefore, increasing the SPF from 15 to 50 only gives 2% more sun protection, while exposing the skin to a much higher adamosis concentration of potentially irritating ingredients. For enhanced sun protection for sensitive skin, one is better off sticking to a SPF 30 and donning a cover-up and wide-rimmed hat.