Proper Sunscreen Use

Julia Belluz does a great job of reviewing some of the frequently asked questions about sunscreens.

Do chemicals in sunscreens hurt me?

• So far, there is no evidence of organ injuries or cancers being caused by chemicals in sunscreens.  Certainly, there is a known risk of skin damage and skin cancer in not using them.

Do sunscreens cause Vitamin D deficiencies?

• No.

Do sunscreens expire quickly or get damaged by heat?

• Consumer Reports found that sunscreens last for years after purchase, but
• they can be rendered ineffective by being over-heated at the beach or in your car.

 Is higher SPF better?

• SPF 30-40 is fine.  Many sunscreens overstate SPF, so if you want a general purpose SPF 15, get SPF 30 just to be sure.  On the other hand, there is very minimal additional benefit at SPF 45 or higher.

How much do I need to use?

• Quite a bit, actually.  It takes about a fluid ounce (1 shot) to cover your whole body, on average.
• Plus, it needs to be replenished every two hours as the chemicals have absorbed harmful UV radiation.