Melanoma Education Foundation
Free melanoma lessons for middle and high school students

May 11, 2017 | Stephen Fine, Founder and President

SPF is Far Less Important than How Much is Applied

Anyone with even the most basic awareness of skin cancer is likely to know that the Golden Rule of practicing sun-safety is to wear sunscreen. The only better protection from the sun’s harmful UV (ultraviolet) rays is to sit inside your home with all the window shades drawn.

Unfortunately, though, there is a key piece of information regarding sunscreen of which far too many people are unaware.

Get the Maximum SPF Out of Your Sunscreen

First, if you’re a regular sunscreen user—excellent job. However, it’s equally important to apply the correct amount. This is the only way to ensure that the sun protection factor (SPF) sun-shield that you’re actually receiving is identical to what is stated on the product.

Many of us, albeit unwittingly, fall into that category. The typical wearer applies a mere 25% of what’s required to achieve a sunscreen’s full safety potential. And while 75% off may be fantastic for department store sales; it is disastrous to our skin. To illustrate further, when 25% of an SPF 100 rated sunscreen is applied, the true SPF isn’t 25-—it’s only 3.2.

Anyone who spends even a brief time reading up on skin cancer and melanoma, will inevitably come across a few of the same specific comparisons used in a wide variety of materials. The one relevant to this post is that the minimum volume of sunscreen to use for each application would be enough to fill a shot glass. It’s also important that it be evenly distributed across any exposed skin, and be re-applied at a maximum of two hours. Even sooner than that if you’ve been sweating or swimming.

Speaking of the latter, spending a day at a beach or pool wearing only a swimsuit is not a good idea. However, anyone who does should use up an entire a 6-ounce container of sunscreen on him or herself by the time they leave. Do you use that much or know anyone who does?

The main point is important to reiterate: you must apply sunscreen much more heavily than that of most users to achieve the rated SPF.

Don’t just get your money’s worth of SPF; get your skin’s good health worth.


*Additional sources: Vitals.lifehacker.com, Onlinelibrary.wiley.com