Generally, people rank oil-free sunblock according to its sun protection factor (SPF) rating. It is also divided into to three main categories, namely, those containing chemical blocking agents, those containing physical blocking agents, and those using a combination of both. A person can also find oil-free sunblocks with varying degrees of water resistance. In addition, the products are available in a variety of forms.
All sunblocks, including oil-free, are designed to either absorb or reflect harmful rays of the sun. These rays, often referred to as ultraviolet A (UVA) and ultraviolet B (UVB) are what cause sunburns, premature aging, and other skin damage resulting from sun exposure. When choosing oil-free sunblock, many people look solely to the SPF rating. That rating, usually a number ranging from 10 to 65, refers to the effectiveness of the product in protecting the skin and the length of time it will remain effective once applied. Typically, the higher the number, the better the protection afforded.
Aside from the SPF rating, oil-free sunblock is considered either chemically based or physically based. These categories refer to the two methods used to protect a person’s skin. Chemical blocking agents protect the skin by absorbing most of the UV energy before it can reach the skin. Oil-free sunblocks that fall into this category contain a combination of chemical ingredients for this purpose. No one chemical, however, can block all UV rays, and while chemical blocking agents generally block most UVB rays, they block only a few UVA rays.
Some oil-free sunblocks use physical blocking agents rather than chemical ones. These blocking agents basically reflect harmful UV rays away from the skin. Most of these products work effectively against both UVA and UVB rays. Titanium dioxide is the most common physical blocking agent, but zinc oxide is also a popular choice.
There are several of these products on the market that use a combination of both chemical and physical blocking agents. Many people feel that the oil-free sunblocks that fall into this combination category are the most effective for sun protection. This is especially true if the product also has a high SPF rating.
In addition to an SPF rating and blocking agent category, certain types of oil-free sunblock offer different degrees of water resistance. There are two basic levels, namely, “water resistant” and “very water resistant.” If the sunblock falls into the first classification, it means that the product will work effectively when wet for about 40 minutes after application. For the later classification, formerly referred to as “waterproof,” it means that the product will maintain its effectiveness for about 80 minutes after becoming wet.
Oil-free sunblock is also available in a variety of styles to suit individual needs and preferences. For instance, it can be found in cream or gel form, or as solid stick. It is also available as a spray-on lotion. Other types are colored and become clear after application to help keep track of the areas of the skin being covered. Still others come in a convenient towelette form, similar to a baby wipe, that can be rubbed onto the skin.