Practice Safe Sun & Protect Against UV Rays

A man applies sunblock on his nose.
A man applies sunblock on his nose.. Aaron Black/Getty Images

Sunblock protects the skin by reflecting UVA and UVB rays like a mirror. Instead of absorbing into the skin, the UV rays bounce right off. The most well known sunblock is zinc oxide. Other commonly used sunblocks include titanium dioxide and talc.

We often use "sunblock" and "sunscreen" interchangeably, when in fact they're quite different. They work differently and contain different chemical properties.

Sunblock literally blocks UV rays. Sunscreen coats the skin, but the skin absorbs UV rays. The key difference comes down to application. Traditional sunscreen must be applied 20 to 30 minutes before sun exposure to allow time for the sunscreen to absorb into the skin, while sunblock works immediately.

If a sunblock and a sunscreen share the same SPF, they're both going to provide the same level of protection. Neither product is inferior. Both sunblock and sunscreen need to be reapplied at least every 2 to 3 hours and after swimming or sweating.

About Sunblock

Sunblocks tend to have a thick, opaque consistency. Think: beach lifeguards sporting white zinc oxide on their noses. Since skin can't be seen through a traditional, thick sunblock, some might prefer to use sunscreen with a thinner consistency.

Sunblock also tends to be greasy and can clog pores, which can be an issue for those with acne-prone skin.

With sun safety becoming increasingly more important, more manufacturers are making skin-friendly sunblock with a spreadable consistency, like the Neutrogena Helioplex line.

Types of Sunblock

SPF ratings are mandated by the FDA, so an expensive moisturizer with an SPF 30 provides the exact same protection as a store brand lotion with an SPF 30.

SPF does not change from brand to brand, but the active ingredients do. Active ingredients can be split into two categories: chemical sunblock and physical sunblock.

Chemical Sunblock

Most chemicals only block a small part of the UV spectrum, therefore chemical sunblock contain several active chemical ingredients. Each ingredient blocks a different region of the spectrum, providing broad spectrum protection. Many of these chemical ingredients block UVB rays; very few chemicals block UVA rays.

Physical Sunblock

There two types of physical sunblocks: zinc oxide and titanium dioxide. Each provides broad spectrum UVA and UVB protection by reflecting UV radiation before it reaches the skin. Zinc oxide and titanium dioxide are physical blocking agents, not chemicals, so they're particularly helpful for those with sensitive skin.

Choosing the Right Sunblock

Ultimately it doesn't matter if you use sunblock or sunscreen. Both are excellent forms of sun protection, so long as you're using a product that has an SPF factor of at least 30.

Sunblocks and sunscreens come in lotions, creams, oils, gels and sprays. They are all equally effective, but only if used properly: that is, applied at least every 2 to 3 hours and after swimming or sweating.


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