Sunscreen and sunblock are products designed to protect your skin from the UV radiation of the sun. Although these terms are used interchangeably, how each one guards your skin is substantially different. This health blurb clarifies what is this difference. Let’s start with the sun’s radiation.
UV (ultraviolet) radiation is a known carcinogen. UVA and UVB are the two types the sun emits. UVA wavelengths penetrate deep into your skin, while UVB mostly affects your skin’s surface. UVB rays are the main cause of a sunburn.
The basic difference between a sunscreen and a sunblock is how their ingredients handle the sun’s rays. Although the ingredients vary by manufacturer, they are typically classified as containing chemical or physical agents.
How chemical agents work is by absorbing and filtering UV rays after they penetrate your skin. These products are sunscreens and the FDA requires Sun Protection Factor (SPF) to be listed on their labels. SPF indicates the protective power a sunscreen has against primarily UVB radiation. Use of at least an SPF 15 is recommended, which in theory means it’ll take 15 times longer to get a sunburn because of it provides protection against 93 percent of the incoming rays.
Titanium dioxide and zinc oxide are physical compounds that block UV radiation from penetrating your skin. Therefore, these ingredients offer full protection against both types of the sun’s rays. These products are best described as sunblock.
A drawback for using a sunblock is the product sits on top your skin rather than being rubbed in. So cosmetically speaking, sunblock is noticeable, whereas sunscreens go unnoticed.
On the positive side, using a sunblock usually causes no side effects. Whereas the chemical ingredients in sunscreens may cause side effects, like:
You may need to try different ones to discover which works best for you without side effects. Typically, skin reactions are caused by para-aminobenzoic acid (PABA), benzophenones, alcohol, fragrances or preservatives. So if you have sensitive skin or are prone to skin allergies to any of these, check the label before you buy.
It’s suggested you apply your chosen sunscreen at least 15 minutes before going out into the sun so a protective film has an opportunity to develop. Sunscreens labeled waterproof or water resistant are best when swimming or heavy sweat producing activities are on your sun soaked agenda.
Generally, the medical community highly recommends the routine use of a sunscreen or sunblock whenever your skin is subjected to extended sun exposure. The justification for this recommendation is to prevent sunburn and minimize the sun’s harmful effects, particularly premature skin aging, skin color changes, cataracts and skin cancer.
However, not all effects from the sun are bad. One example is UVB rays trigger the chemical and metabolic reactions that ends with the production of vitamin D. Yet, some argue the sun is not necessary for getting your recommended daily allowance of this vitamin because most get enough in their diets. And if not, taking it in supplement form or consuming products fortified with it is better.
Another benefit from the sun is the suggestion that sunlight hitting your skin and eyes helps counter the effects of seasonal affective disorder. An argument against it is that light therapy boxes are designed do the same thing without the risk.
A final note, if you are taking antibiotics or antihistamines, sun sensitivity is a potential side effect of these drugs.