Sunscreens should be used in conjunction with shade, clothing, hats and sunglasses, not instead of them. Sunscreens may absorb enough of the radiation to stop sunburn but photochemical reactions, DNA lesions and other types of damage may still occur. There is still scientific debate as to whether sunscreens alone protect against melanoma and other skin cancers. Sunscreen is usually composed of a combination of chemicals designed to absorb or block as much of the UVR spectrum as possible. Sunblocks such as titanium dioxide and zinc oxide on the other hand, provide physical blocks from all UVR wavelengths.
Sunblocks function similar to tightly woven protective clothing or deep shade.
There are transparent sunblocks available. To achieve the SPF value listed on the sunscreen container one must apply 2 mg per square centimeter. This is a very large amount. Most people only apply about 0.5 mg per square centimeter reducing their protection to one quarter of the SPF stated on the container. Practice regular skin self-examination Skin cancer is highly curable if detected early.