How to Choose Between Sunscreen versus Sunblock

Factors to Consider when Choosing a Sunblock

Summer is not yet over, recent weather forecast show that the summer heat is still on. Aside from beating the high temperature and staying hydrated, it is also important to protect your skin from the harmful UV rays of the sun especially when you're going out or planning for a summer vacation.

Those who will be staying under the sun for longer periods will need a stronger sun protection cream like sunblock or sunscreen. Both can shield you from UV rays but they work in different ways. Read through the article to know the difference of sunblock from sunscreen and other important factors to keep your skin healthy.

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1. Types of ultraviolet radiation

UVA and UVB are the two types of ultraviolet radiation that can harm the skin. With prolonged exposure, these ultraviolet radiation promotes premature skin ageing and increases one's risk of having skin cancer.

UVA penetrates deep into the skin and is responsible for wrinkling and skin sagging. It causes premature skin ageing and supports the effect of UVB towards cancer formation. UVB on the other hand is more intense on the superficial layer of the skin. This is the one which causes redness or sunburn.

2. The right sun protection

Sunscreens are usually interchanged with sunblock but they are different terms. Sunscreen absorbs UV rays and diffuses it to the skin. It contains chemical ingredients that creates a thin film on the skin to reduce the harmful effect of UVB rays. Others say that it converts the UV rays into less damaging radiation.

Sunblock works by making a physical barrier rather than a chemical one mentioned previously. Sunblock creates a thick film which acts as a barrier which can actively block both UVA and UVB rays. They offer a higher degree of sun protection compared to sunscreens. According to the American Melanoma Foundation, sunblock is a better option because of its broader action.

• If the product label do not include the type of sun protection, you can look at the ingredients to distinguish sunblock from sunscreens. Sunblock contains zinc oxide and titanium dioxide while sunscreens do not.  
• Creams, lotions, and sprays are equally effective so you don't have to worry about those.
• If you're going to stay under the sun for longer duration, sunblock is a better option. Sunblock is also best for those who have sensitive skin since it physically blocks the entry of ultraviolet radiation.

3. Application & exposure time

Sunblock are immediately effective right after application because of the physical barrier made by the ingredients. If you opt for sunscreens, you need to wait for at least 20 minutes before it could take effect. That's why it is usually advised to apply sunscreen in the morning or before going outdoors.

Water resistant sunscreens lose effectiveness after 40 minutes of exposure, while waterproof sunblock start to lose effectiveness after 80 minutes of exposure. Reapply often especially after swimming or heavy perspiration. Also, be sure follow the product's directions for reapplication.

4. SPF - Sun Protection Factor

The sun protection factor (SPF) denotes the product's ability to block UV rays.  Most Dermatologists recommend an SPF of at least 30 to ensure adequate sun protection. Choosing a product with an SPF of 30-50 is ideal since an SPF of more than 50 is actually no longer beneficial. Keep in mind that the SPF do not equate with the protection time, for example:

• SPF 15: 94% protection
• SPF 30: 97% protection
• SPF 45: 98% protection

Reference:

• AMF. Facts About Sunscreen. American Melanoma Foundation. Retrieved 26 May 2015 from http://www.melanomafoundation.org/prevention/facts.htm 
• No Author. Sunscreens Explained. Skin Cancer Foundation. Retrieved 26 May 2015 from http://www.skincancer.org/prevention/sun-protection/sunscreen/sunscreens-explained.