It’s time for sunscreen bootcamp!
First, let’s talk about why we use sunscreens.
Energy from the sun comes in the form of light. The light we see is called visible light. The light we don’t see with higher energy than visible light is called ultra-violet light, or UV light.
Ultraviolet light, for all intents and purposes, is divided up into 3 groups: UVA, UVB, and UVC. UVA is less “intense” and UVC is more “intense”. UVC is predominantly blocked by our ozone layer, so it is not a major concern.
UVA and UVB, on the other hand, both pose significant health risks. The intensity of these rays can cause sunburn and damage in the form of aging, wrinkles, and eventually cancer.
Which is worse? Well, UVB is more intense and poses greater health risk. BUT, UVA is much more prevalent – you’re exposed to about 50 times more UVA than UVB.

So, we must protect against our exposure to these. Sunscreens are how we do so.
Protecting Yourself From The Sun
Let’s now discuss SPF. SPF stands for “Sun Protection Factor“. SPF is a measure of a sunscreen’s ability to protect against UVB only. This very important! Only “broad spectrum” sunscreens protect against UVA. With upcoming FDA regulations, broad spectrum sunscreens must protect equally against UVA and UVB.
The number associated with SPF is actually about time. SPF 15 means it will take 15 times as long for your sun to redden than if you had no protection. SPF 30 means it will take 30 times as long for your skin to redden.
Once you hit SPF 30, you are “blocking” about 97% of harmful rays. Increasing the SPF beyond 30 will gain you only 1-2% extra protection. Therefore, SPF 30 is all that is necessary. The key is using the proper amount and reapplying every 2 hours.
Mineral vs Chemical Sunscreens
Protection from the sun comes from either a variety of chemicals or from minerals. (a little tidbit: In Europe, mineral sunscreens are illegal).
FDA Approved Sunscreens
Chemical sunscreens form a thin, protective film on the surface of the skin and absorb the UV radiation before it penetrates the skin.
The mineral-based sunscreens are insoluble particles that reflect UV away from the skin. Most sunscreens contain a mixture of chemical and physical active ingredients.
It’s really a matter of choice. Our preference is to recommend mineral-based sunscreens. We tend to recommend oil-free sunscreens for the face to decrease chances of getting pimples.
The Key To Protection – Applying it Right
All the protective effects of sunscreen come if the correct amount of sunscreen is applied. For the average adult, 3 tablespoonfuls (1 and 1/2 ounces) should be applied every 2 hours.
Most people apply only 1/4 to 1/2 of the recommended amount. A recent article in Drug and Therapeutics Bulletin states that this equates to a true SPF of only 2.3-7.1.
Sunscreens must be applied 20 minutes prior to needing protection. Some sunscreens are labelled as “instant protection” now must submit data supporting this claim to the FDA or have that claim removed from the package.
What about water? Some sunscreens currently are labelled as water or sweat proof. This claim soon has to be proven by providing protection for 40-80 minutes while sweating or swimming. Until new regulations take effect fully, please reapply sunscreen IMMEDIATELY following sweating or swimming.
In Summary
In an ideal world…
- Use a true broad spectrum SPF 30 sunscreen
- Apply 20 minutes prior to sun exposure
- Use 3 tablespoonfuls over all exposed areas every 2 hours
- If you sweat or go swimming, reapply immediately
