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May 26, 2020

Sunscreen: How to Select, Apply, and Use It Correctly

Sunscreens help shield you from the sun’s dangerous ultraviolet (UV) rays in two ways. Some work by scattering the light, reflecting it away from your body. Others absorb the UV rays before they reach your skin.

When To Apply Sunscreen
  • Apply sunscreen at least two times a day. First application should be approximately 30 minutes before being in the sun so that it can be absorbed by the skin and less likely to wash off when you perspire. Second application should be around midday (12-1pm).
  • Application of sunscreen is advisable even on cloudy days because although UVB radiation is minimal, UVA radiation (known to brake down collagen and cause skin cancer) is always present during daytime. Also most lamps irradiate small but continuos ammounts of UVA when lit.
  • Remember to reapply sunscreen after swimming or strenuous exercise.
  • Apply sunscreen often throughout the day if you work outdoors (every two hours), and wear hats (caps do not protect the ears and nape of neck area) and protective clothing (long sleeves shirts and long pants).

How To Apply Sunscreen
  • Shake well before use to mix particles that might be clumped up in the container. Consider using the new spray-on or stick types of sunscreen.
  • Be sure to apply enough sunscreen. As a rule of thumb, use an ounce (a handful) to cover your entire body.
  • Use on all parts of your skin exposed to the sun, including the ears, back, shoulders, and the back of the knees and legs.
  • Apply thickly and thoroughly.
  • Be careful when applying sunscreen around the eyes.

What To Look for When You Buy Sunscreen
  • Pick a broad-spectrum sunscreen that protects against UV-A and UV-B rays.
  • Read product labels. Look for a waterproof brand if you will be sweating or swimming. Buy a nonstinging product or one specifically formulated for your face.
  • The SPF factor rates how effective the sunscreen is in preventing sunburn caused by UVB rays. If you would normally burn in 10 minutes, SPF 15 multiplies that by a factor of 15, meaning you could go 150 minutes before burning.· People who have very fair skin, who suffer conditions like lupus or are taking medication that makes your skin more sensitive to sunlight should consider SPF 30 or higher. Keep in mind that the higher the SPF, the smaller the increased benefit: contrary to what you might think, SPF 30 isn’t twice as strong as SPF 15. While SPF 15 filters out 93% of UVB, SPF 30 filters out 97%. UVA protection. amazon site down Look for a sunscreen that contains at least one of the following: ecamsule, avobenzone + octocrilene, oxybenzone, titanium dioxide, zinc oxide.
  • Buy a brand that does not contain para-aminobenzoic acid (PABA) if you are sensitive to that ingredient.
  • Try a sunscreen with different chemicals if your skin reacts badly to the one that you are using. Not all sunscreens have the same ingredients.
  • Use a water-based sunscreen if you have oily skin or are prone to acne.
  • Be aware that more expensive does not mean better. Although a costly brand might feel or smell better, it is not necessarily more effective than a cheaper product.
  • Be aware of the expiration date because some sunscreen ingredients might degrade over time.

Modified from: and

Submitted by: Dr. Jorge Lopez-Granja