7 Things To Know About SPF (Hint: A Higher Number Isn’t Always Better)

May 8, 2013

When I say that the sun is our frenemy, I’m kind of joking. But kind of not.

The sun is a life-giver! Without the sun, life on this planet wouldn’t even be possible. On an everyday basis, the sun can brighten our day and provide warmth. But, at the same time, the sun is also sneaking in a lot of long-term damage to our skin.

Our skincare routine should always include some kind of sun protection.

Most people are happy to just slather on some kind of product containing the highest number of SPF that they can find, without a clue as to what that number means.

So, today I’m going to quickly break down the important things you need to know about SPF in sunscreens.

And why a higher number isn’t always necessarily better…


  • 1) SPF stands for Sun Protection Factor. This was a number introduced in 1962 to measure a sunscreen’s effect against UVB rays, the type of UV ray chiefly responsible for sun burn and skin cancer.
  • 2) The SPF number stands for how long you can stay in the sun without getting burned. The idea is, if you tend to burn under the sun within 10 minutes of exposure, using an SPF 10 product will multiply the time you can stay out in the sun by 10 without getting burned (in this case, 100 minutes).
  • 3) SPF number indicates protection only against UVB rays. It’s important to look for a “broad-spectrum” label which will protect against both UVB rays and UVA rays, the other type of UV ray that can penetrate deeper into the skin and cause long-term photo damage.
  • 4) Increasing the SPF number does not exponentially increase your level of protection. For example, an SPF of 15 absorbs 93.3 percent of UVB rays, but an SPF of 30 absorbs 96.7 percent. Even though the SPF number has doubled, the UVB absorption rate has increased by only 3.4 percent.
  • 5) Suncreen’s effectiveness decreases when exposed to water or sweat. Even if it is waterproof. All types of sunscreen break down over time, especially after exposure to water. So re-apply every 2 hours to keep your skin safe.
  • 6) No matter how high the SPF, sunscreen can protect only the skin it covers. Your whole body is vulnerable to skin cancer, not just the areas that burn easily or wrinkle faster. Areas that tend to be overlooked are the lips, the backs of your hands and ears, and the tops of your feet.
  • 7) After applying sunscreen, wait 15 to 30 minutes before stepping out into the sun. This gives chemical sunscreens enough time to be fully absorbed into the skin.

Other important things to remember:

To have well-rounded coverage, SPF protection should be combined with protective clothing and sun avoidance during the hottest and brightest parts of the day, usually between 10 am and 4 pm, when UVB rays are strongest.

SPF strength is less important than frequent application!!

And finally, you should be protecting your skin from the sun on a daily basis, no matter what the season! You do know that, right??

I know that summer is the season when people love to get their tan on. And for those people, I’m going to leave you with a very powerful image of what the sun can do to your skin over time.

Maybe you’ve already seen this? But if not, this is a photo from a New England Journal of Medicine study, about a 69-year-old man who drove a truck for 28 years, and was exposed to the sun only on the left side of his face.

Sun Damage

Eep! The sun really is our frenemy.

7 thoughts on “7 Things To Know About SPF (Hint: A Higher Number Isn’t Always Better)

  1. Luchessa

    This is a really important article dear. I think we all kind of heard about sun screen, but rarely think about the numbers or ingredients that they consist.
    It’s great to be reminded of that all. I should get a good daily cream for my face with a SPF 15 in it. Any tips (for sensitive & combination skin)?

    1. Kareen

      Hi Luchessa! I think so too. It’s important to shed some light on what those numbers means. I didn’t delve too much into ingredients and chemical vs physical sunscreens. But next time! As you know, I am a big fan of Andalou Naturals Daily Defense Lotion with SPF 18, and I have normal/combination skin. I’ve been looking for other good moisturizers with SPF, so I’ll let you know if I find some good ones for sensitive & combination skin type.

    1. Kareen

      Hey Kris! I saw that picture a few months back and it really stayed with me! I read your article before, but I’ve just left un petit commentaire 😉 bixxou

  2. Emilia

    Wow! That last pic really drove your message home! I love the sun because it clears up my skin without creams or lotions. What do you suggest to either get enough (but not too much) sun-shiny rays? I see you mentioned Andalou Naturals Daily Defense but do you know of anything that is specifically for problem skin?(sunscreen clogs my pores)

    1. Kareen

      I love the sun too! I love being sun kissed, but I only need a little bit of it each day to brighten my mood. And as for my Vitamin D needs, I take a vitamin D supplement.

      As for naming a sunscreen for your skin type, I don’t really have one off of the top of my head. All I can say is that there are 2 kinds of sunscreens–physical and chemical. I’ve read some accounts that say physical sunscreen particles are too big to enter and clog pores. Physical sunblocks are composed of zinc oxide and titanium oxide. These particles aren’t absorbed into the skin. They just reflect and bounce off the light from the sun. So I would suggest looking for sunscreens that mainly contain these ingredients. Specifically zinc oxide, since it protects against the entire spectrum of UVB and UVA rays and has low comedogenicity. But, everyone’s skin is different and there’s always a chance your skin might react badly to one of these ingredients.

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