What is SPF?
Is SPF 45 more effective than SPF 30?
What is UV and are there more than one type of UV?
How do you assess the UV exposure you can expect to receive during an outing?

What is SPF?

SPF is the abbreviation for Sun Protection Factor. In layman's language, one SPF is the amount of time in minutes that it takes your unprotected skin to become lightly reddened or irritated (erythemal) from being exposed to the sun. Each person has a different SPF based, among other things, on his/her skin type, amount of skin pigment (skin darkness), existing tan, and prior sun exposure.

The SPF number on sunscreen products indicates approximately how many times your normal SPF time is multiplied by correctly applying that product. As an example, if your personal SPF is 30 minutes and you choose to use an 8 SPF product, you would extend your time to reach the sensitivity to the sun as described above by eight (8) times.

The time would be calculated by multiplying your personal SPF time of 30 minutes by the SPF number on the sunscreen product which was 8. The total, in our example, is 4 hours (240 minutes). That means, in our example, the sun would have the same effect on your skin using properly applied SPF 8 sunscreen in four (4) hours as it would in one half hour without sunscreen.

Is SPF 45 more effective than SPF 30?

SPF 30 is very effective delivering 96.5% of UV protection without the side effects. SPF 45 and above provides minimal protection and the added active ingredients can be harsh to the skin and can result in allergic reactions. View this chart for details.



% of UV Protection

Very weak protection



Minimal protection



Dermatologist recommended protection     



Dermatologist recommended protection



Dermatologist recommended protection



High concentrations of active ingredients*



Very high concentrations of actives*



What is UV and are there more than one type of UV?

UV is the abbreviation for Ultraviolet Radiation. These invisible rays produced by the sun are commonly classified in one of three categories (UV- A, UV-B, or UV-C) and are the major cause of sunburn, skin aging, and in some cases, skin cancer.

UV-A rays remain rather constant in intensity throughout the year and penetrate more deeply into the skin's layers than UV-B rays. UV-A rays are major contributors to sunburn, wrinkling, and premature aging.

UV-B rays are more intense at locations closer to the equator, at higher altitudes, and during the summer months. They are stronger than UV-A rays and are the most common cause of sunburn as well as contributing to premature aging, and wrinkling of the skin. They also can contribute to skin cancer.

UV-C rays are the most dangerous and strongest of the UV band. However, they normally do not reach the Earth's surface because they are filtered out by the ozone layer of the atmosphere.

How do you assess the UV exposure you can expect to receive during an outing?