Updated 3/2017-- photos and all links (except to my own posts) removed as many no longer active.
Patients (and friends) often ask me which sunscreen they should use. Often this is more for skin aging protection than sunburn protection. The answer is the same. The best sunscreen is the one they will use. It has to "feel" good to them--not be too greasy, not have the wrong scent, be the right consistency (lotion vs cream). It will not matter if it is SPF 15 or 3o if it never gets used. The next thing I tell them is to use it daily, all year around, especially on the face and neck. If they are in the habit of applying sunscreen to their face daily (even on overcast days), it won't be forgotten.
For a more scientific answer, you need both UVA and UVB protection. It is the UVA rays that are most responsible for wrinkling and aging the skin. It is the UVB rays that are the most responsible for the sunburn. The best sunscreen is at least an SPF 15 and has a sunblock component also. The SPF rating reflects the product's ability to screen or block UVB rays only. SPF 15 blocks approximately 93 percent of all incoming UVB rays. SPF 30 blocks 97 percent; and SPF 50 blocks 99 percent. To protect against the UVA rays, the product needs to have avobenzone (Parsol 1789), ecamsule (Mexoryl), titanium dioxide, or micro-zinc oxide.
- Apply the sunscreen 20-30 minutes before going outside.
- Use enough. To ensure that you get the full SPF of a sunscreen, you need to apply 1 oz – about a shot glass full.
- Reapply after getting out of the water or toweling off. Even "water-proof" sunscreens are not usually "towel-proof".
- Reapply every two hours when outside at a beach, etc. for adequate protection.
- Use even on a cloudy day. Up to 40 percent of the sun's ultraviolet radiation reaches the earth on a completely cloudy day.
- Shield your eyes with UV-blocking sunglasses. Squinting caused wrinkles around the eyes. The UV rays can cause cataracts.
- Wear a wide-brim hat to help protect your head & neck.
- Don't forget to apply lip balm with SPF 15 or higher.
The Skin Cancer Foundation grants its Seal of Recommendation to products that meet the Foundation's criteria for effective UV sun protection products. If you use a product make especially for the face (ie MD Forte Total Protector SPF 30 or Clinique's Super City Block Oil Free Daily Face Protector SPF 25) it will be less likely to cause skin irritation or acne outbreak with daily use. So spend more money on the face and then if you need to save money, do so on the body sunscreen (ie NO-AD SPF 30 Sport Ultra Block Lotion, Coppertone Water Babies Sunscreen SPF 45).