What are UVA and UVB rays?

If you’re confused about how to pick a sunscreen, you’re not alone. Here’s some practical advice to help you sort through the sprays and lotions and understand the alphabet soup of SPF, UVA and UVB to find the best sun protection for you.

UVA rays cause premature aging, while UVB rays can burn your skin. An easy way to remember is “A for aging” and “B for burn.” But whether you’re talking UVA or UVB, both are damaging. So choose a sunscreen labelled broad-spectrum or full-spectrum, which means the product is designed to protect you from both.

Sunscreen ingredients

Chemical sunscreen ingredients, such as PABA (para-aminobenzoic acid) and cinnamates, absorb UV rays and convert the sun’s radiation into heat energy, while physical sunscreens (such as zinc oxide and titanium dioxide) deflect and scatter the rays before they penetrate your skin. Both types can be effective and safe if used properly.

Which SPF is best?
Sun protection factor, or SPF, measures how well sunscreens repel UVB rays. In other words, how much longer it takes you to burn when wearing sunscreen compared to skin without any protection. If it takes you 10 minutes to burn, a properly applied SPF 15 can extend this timeframe to 150 minutes.

It’s surprising to note, however, that a higher SPF only offers minimal increased protection. For example, SPF 30 doesn’t provide double the protection of SPF 15. In fact, SPF 15 filters out 93 percent of UVB rays, while SPF 30 filters out 97 percent.

There is no SPF-equivalent for measuring UVA protection. So pay attention to the sunscreen’s ingredients for effective UVA-blocking components. Keep an eye out for at least one of the following: ecamsule, titanium dioxide, sulisobenzone, avobenzone, oxybenzone or zinc oxide.

Choosing the right sunscreen
Sunscreens made for dry skin may not suit people with acne or rosacea. The following guide should help you find the right sunscreen for your skin’s needs.

1. For children’s skin: The physical sunscreens zinc oxide and titanium dioxide tend to be better tolerated by people with sensitive skin and can usually be found in sunscreens for babies and children. Spray sunscreens should not be applied directly to the face; sprays should be misted into the hands, then spread on the face.
2. For allergy and acne prone skin: Patients with allergy-prone skin or conditions such as acne or rosacea should avoid products containing preservatives or fragrances, as well as those containing PABA or oxybenzone. The ingredients least likely to cause skin reactions are the physical sunscreens, as well as those made with salicylates and ecamsule. Patients with acne, may find gel formulas, which usually contain alcohol, more drying and less likely to aggravate acne. Acne-prone patients should avoid greasy sunscreens (often marketed as “creams”), since they may exacerbate breakouts; the UVB filter ensulizole has a lighter, less oily consistency than most other chemical sunscreens. Since some acne medications increase sun sensitivity, making wearers more vulnerable to burning and skin damage, rigorous daily sun protection is especially important.
3. For dry skin: Dry skin can benefit from moisturizing sunscreens. Numerous moisturizers are used in sunscreens; popular ones include lanolin, oils, and silicones such as dimethicone. Moisturizing sunscreens are often formulated as creams, lotions, or ointments, so look for these terms on the label.
4. For people with melasma, a history of skin cancer, or very fair skin: For patients with a blotchy brown discoloration of the skin called melasma, those who have had skin cancer, or those who are very fair, sunscreen with an SPF of 30+ is recommended daily for extra protection. Since most people do not actually apply enough sunscreen to achieve the SPF listed on the container, frequent reapplication (after two hours out of doors or immediately after swimming or sweating heavily) is especially important.
5. For darker skin tones: Individuals with darker skin who tan easily and rarely burn may feel they do not need to use sunscreen. However, like sunburn, a tan is the result of DNA damage from exposure to the sun’s harmful UV radiation. Darker-skinned people may also be wary of using physical sunscreens, especially titanium-based products, because they can look chalky and white on the skin. Chemical sunscreens are also an option; look for a broad-spectrum sunscreen with an SPF of 15+.
6. For the older person: Although older individuals may have already received large amounts of UV light exposure in their lifetime, they can still benefit from sunscreen use. At any age, unprotected sun exposure accelerates skin aging, leading to age spots, wrinkles, sagging, and leathery skin. Older people with decreased mobility may have a hard time applying sunscreen to areas such as the legs and back; for them, spray-on sunscreens may be a great option — they are now available both in chemical and physical formulations. Sprays should be applied until an even sheen appears on the skin.

You’ve found the perfect sunscreen – now use it!
In general, apply sunscreen about 20 minutes before sun exposure to give your skin plenty of time to absorb it. Whether you are using a lotion or spray, apply a thick coat and thoroughly rub it in. Don’t overlook areas like the back of the neck, tips of the ears and tops of the feet. And reapply every two hours. If you’re sweating or playing in the water, consider reapplying more often. Water resistant doesn’t mean waterproof – and it’s better to be safe than sunburned.
And keep in mind, sunscreens expire. Check the expiration date on the bottle and toss it in the trash if it’s past its prime.

Conclusion
Sunscreen is an important part of a sun protection regimen that should also include seeking the shade, avoiding UV tanning, and wearing protective clothing, including a broad-brimmed hat and UV-blocking sunglasses. By educating yourself about your many sunscreen options, you can be confident that the product you choose will fit your particular needs, offering you the best protection from the sun’s harmful rays — and helping to ensure that you use it regularly. After all, the sunscreen you apply consistently is the best sunscreen of all.