By Mary Molinari


sunscreenYou know that premature aging of skin and skin cancer are harmful effects of the sun. You are also aware of the benefits of using a sunscreen. But (SPF 15? SPF 30? Zinc oxide? or is it titanium dioxide? UVA? and UVB ?) all those brands and terms leave you baffled!

So lets start with the basics:

How does sunscreen work?

Sunscreens aid the body’s natural defenses in protecting against harmful ultraviolet radiation from the sun. They contain chemicals that work by absorbing, reflecting or scattering the sun’s ultra violet radiation on the skin. This helps prevent sunburn and other skin problems.

How do I begin?

First you are going to look at the SPF number and if there is protection against UVB and UVA rays.

UVB and UVA rays?

The sun gives off two types of harmful–ultraviolet (UV) radiation. One is the Ultraviolet B (UVB) ray which affects the outer layer of your skin. It is primarily responsible for sunburns. The other is the Ultraviolet A (UVA) ray which can penetrate into the thickest layer of your skin causing cancer and premature skin aging. Excessive exposure, however, to both forms of UV rays can lead to skin cancer.

So what is this SPF?

SPF is an acronym for Sun Protection Factor. It essentially measures the effectiveness of sunscreen. The number refers to the product’s ability to stop your skin from burning. Levels of SPF range from 2-80 and therefore vary in their ability to protect the skin from sun damage. Generally, the higher the SPF rating, the greater protection, and the longer you are able to stay in the sun before burning.

But…be careful !

The Sun Protection Factor number only applies to UV-B rays. The SPF does not indicate protection from UV-A rays.

So then how do I know which is best for me?

There are formulas based upon time it takes for you to burn in the sun and multiplying it by a SPF number. Unfortunately, there are too many variables to make this reliable. Dermatologists recommend you look for labels that specify broad or multi spectrum UVA and UVB protection, are water resistant and have an SPF of 15 or higher. To be effective against all UVA rays it should contain avobenzone, zinc oxide, or titanium dioxide. The only way to determine this is to look at the ingredients. Because of the altitude in Mexico and if you are light-skinned, spend a lot of time in water or direct sun, a SPF of 30 or higher may be a better choice.

Do products expire?

All sunscreens should be stable and at their original strength for at least three years.

Is a sunblock the same as a sunscreen?

No, sunblock works in a different manner than sunscreen but does blocks both UV-A and UV-B rays. Some feel it is a better option for skin protection, but it is not as commercially available as is sunscreen.

What is the best way to apply sunscreen?


Liberally (a handful) to clean, dry, sun-exposed skin areas 15-30 minutes before exposure to the sun for proper absorption

At least every two hours, this is more critical after swimming or perspiring heavily. Even “water-resistant” sunscreens may lose their effectiveness after 40 minutes in the water. Sunscreens rub off when you towel dry so reapply.

No matter your race or ethnic origin. People with dark skin do need sunscreen.

Lip balm with SPF 15 once every hour while you are in the sun and after activities that remove it from the lips such as eating and drinking.

When overcast because 80 per cent of ultra-violet radiation is still present.

When in the shade, concrete and water reflect harmful rays.

Last word

Sites for approved sunscreens

For more information about Lake Chapala visit:

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