Sunscreen: The Last Line Of Defense


Sunscreen is one of the most scientifically proven ways to prevent aging of the skin, skin cancer and sun damage. It is commercially available in personal care products such as daily facial moisturizers, facial sunscreens, sprays, gels, sticks and cosmetics.

Sunscreen comes in two forms: physical and chemical blockers. Physical blockers consist of zinc or titanium dioxide, which reflect light. Chemical blockers are organic compounds that need to be absorbed in the skin where they then protect our skin from ultraviolet light (UV). The best sunscreens will block both UV-A (aging) and UV-B (burning) wavelengths and are considered broad spectrum. The American Academy of Dermatology recommends a broad-spectrum blocker that is water resistant with an SPF of 30 or greater.

But is sunscreen really delivering sun protection for us, and are we using it correctly? The product label will usually recommend reapplication every 40-80 minutes in most cases. The rates of reapplication, in reality, have been shown to be very low and sunscreen is frequently applied in inadequate amounts, leading to missed spots, and ultimately undesired UV exposure. While being most apparent as a sunburn, frequent low-grade UV exposure is cumulative.  Ultraviolet light causes damage to the DNA of our skin cells and also thins our skin over time, leading to loss of the collagen and elasticity that gives our skin its youthfulness.

One of the most vulnerable times for our skin is trips to sunnier climates closer to the equator. It is important to be aware that the ultraviolet exposure in places such as Florida, the Caribbean and Mexico are several times higher than the ambient ultraviolet in the mid-Atlantic. Ten minutes by the pool on vacation may be equivalent to an hour outside in Maryland.

Very strong UV exposure from these trips can accumulate over time and accelerate skin aging dramatically. It is these intense exposures, though somewhat infrequent, that can significantly increase future risk for skin cancer. For fairer skin types, recent studies have shown that the individual lifetime risk is as high as 30% to 40% for skin cancer.

Sunscreen, although helpful, is only one piece of the skin protection puzzle. Use of sunscreen should not be a blank check to do any activities outside for hours on end. If your job or hobbies require you to be outside on a regular basis, it is time to really up your game with sun protective habits, clothing and hats in addition to sunscreen in exposed areas. As for Vitamin D, rely on supplements and natural dietary sources and don’t expose your skin to ultraviolet radiation to obtain it.

The best way to prevent unnecessary sun exposure is to plan outdoor excursions outside of the hours of 10:00am to 4:00pm when the vast majority of UV exposure occurs. Sunscreen is also a good idea to use year-round to prevent aging of the skin. UV exposure is cumulative and protecting our face, neck and tops of our hands even in winter months can allow the skin to flourish.

Given what we know about the benefits of sunscreen, it should always be part of any skin care regimen. If you are unsure what products or sunscreen may be best for your skin, schedule an appointment with your local board-certified dermatologist, get a baseline check skin examination and ask for sunscreen recommendations.

Lane Neidig, MD, FAAD, is a board-certified dermatologist who practices medical, surgical and cosmetic dermatology for all ages at Modern Dermatology of Maryland in Annapolis. For more information, contact Dr. Neidig’s office at 410-216-0993, by email at or visit


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