Apply sunscreen approximately 30 minutes before being in the sun (for best results) so that it can be absorbed by the skin and less likely to wash off when you perspire.
Apply sunscreen often throughout the day if you work outdoors, and wear hats and protective clothing.
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 and has a sun protection factor (SPF) of at least 15.
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.
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.