Sunscreen- What The SPF?

Yesterday was one of the most beautiful summer days at Delray Beach.  There was a cool breeze, not a cloud in the sky and the sun was shining brightly.  I quickly sprayed on some Neutrogena sunblock and laid down to bake.  My boyfriend meticulously piled on his 70 SPF sunscreen and I laughed at the thick white layer on his skin that just didn’t seem to fade no matter how hard he rubbed it in.

Jeremy got the last laugh though.  My face is bright red today and it hurts.  In addition to not putting enough sunscreen on my face, I also missed random spots on my chest, arms and stomach.

After a bad sunburn a few weeks ago, Jeremy refuses to use that Neutrogena spray that I used.  He now swears by the thick, sticky lotions with the highest SPF possible.  Four, 8, 15, 30, 45, 70, SPF, UVA, UVB- WTF?  What do all those numbers mean, and what should you consider when shopping for sunscreen?  I always feel a little overwhelmed when trying to decide which one might be best for me, so I have done a little research to figure out what it all means.

We use sunscreen to block ultraviolet light from damaging the skin. There are two categories of UV light- UVB causes sunburn, and UVA has more long-term damaging effects on the skin, like premature aging.  Too much sun exposure over time can take quite a toll, but sunscreen plays an important role in protecting your skin against sunburn, wrinkles, premature aging and skin cancer.  It should be applied anytime you plan on being outdoors, even just for a little while.  You don’t want to end up looking like this lady:

SPF stands for Sun Protection Factor, but the higher the number does not necessarily mean that it’s better.  The SPF number is simply a standard for how long you can tolerate the sun without burning.  For example, if you can stay in the sun for 10 minutes without burning, an SPF of 15 should allow you to spend 150 minutes out in the sun before burning.  This is assuming that you are using the ideal amount of sunscreen, which is enough to fill a shot glass.

Before you grab your calculator and head to the beach, you should know that this equation is not always accurate and doesn’t cover everything.  A higher SPF number may mean more sun-exposure time, but UVB absorption must be considered as well.  People get confused because the absorption number does not increase exponentially with a higher SPF.  For example, an SPF of 15 absorbs 93.3 percent of UVB rays, but an SPF of 30 absorbs 96.7 percent. The SPF number has doubled, but the absorption rate has increased by only 3.4 percent.

Because of this, according to the FDA, anything higher than 30 SPF is not much better than 30.  The bottom line is that you should be wearing enough SPF 30 with broad-spectrum UVA/ UVB protection and reapplying often.  Remember to reapply after going swimming or sweating a lot, because despite being advertised as waterproof, all sunscreens decrease in effectiveness when exposed to water.

Sunscreen use alone will not prevent all of the possible harmful effects of the sun.  It is also important to limit your time in the sun and wear protective clothing and a hat to protect your face.  Here are a few other random facts that will help you protect your skin:

  • The sun’s rays are the strongest from 10:00 a.m. to 4:00 p.m, especially during the late spring and summer.
  • Reflected glare from water and snow also can increase your exposure to UV radiation.
  • Sunscreen typically maintains its strength for about 3 years. After that time period, it is less effective.
  • Apply sunscreen at least a half-hour before you go outside.
  • Up to 80% of your total lifetime sun exposure is likely to take place before you reach the age of 18.
  • Make-up with SPF isn’t enough to protect your skin.
  • Skin cancer is the most common of all cancers. It accounts for nearly half of all cancers in the United States.

Stay safe, my friends!

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18 thoughts on “Sunscreen- What The SPF?

  1. ecobeaut says:

    Ouch, I’m feeling you on the sunburn. I had many bad ones, especially when I was a teen and worry-free about UVA/UVB rays. I agree with you though, applying SPF 30 diligently will be better than slathering SPF 100 just once. Recently the FDA is starting to move on regulating sunscreens ( so that sunscreens can only be SPF 50 and lower. I think that’s fantastic! People really need to know the facts about SPF and being in the sun’s rays. Thanks for your comment on my natural sunscreen post and great review too 🙂

  2. Yeah I think it’s a good idea. People are mislead into thinking they are much safer with 70 and 80 SPF when they’re really not.

  3. mommylounge says:

    Thanks for visiting the UV Skinz blog! You point out some good classic tips in your post. There is definitely a difference in coverage when you compare sprays to lotions. My favorite contain zinc oxide which a physical blocker, but the best protection (safer for you and the environment) is UV protective clothing. 🙂

  4. trikatykid says:

    Just what I needed. Do you know if sunscreen expires? Should we replace our bottles that are from “who knows what year?” This was useful – I don’t know if you read my comment on the PHYT blog but I burned this weekend while on a 3-day rafting trip. I’m sure some of it had to do with the fact that I was in and out of the water and had very little (other than clothing, NO sun cover) .. but I was surprised I got as much color as I did. Thanks again or the post. It was great.

    • Yes, sunscreen does have an expiry date!

      • trikatykid says:

        Where do you find it?! No wonder I got burned!!!

      • I’ve found it on the very end of the sunscreen bottle. It’s the sort of bottle kind of like a toothpaste tube, tapered at the end. On that very tapered end is the expiry date. You definitely have to look for it.

      • trikatykid says:

        Yes, thank you. This is very helpful! I will buy new sunscreen every season just to be safe!

      • The American Academy of Dermatology has this on their site
        Personally, I choose a sunscreen that has an expiry date on it.
        “Q. Can I use the sunscreen I bought last summer, or do I need to purchase a new bottle each year? Does it lose its strength?

        Dermatologists recommend using sunscreen every day, not just during the summer. If you are using sunscreen every day and in the correct amount, a bottle should not last long. If you find a bottle of sunscreen that you have not used for some time, here are some guidelines you can follow:
        The FDA requires that all sunscreens retain their original strength for at least three years.
        Some sunscreens include an expiration date. If the expiration date has passed, throw out the sunscreen.
        If you buy a sunscreen that does not have an expiration date, write the date you bought the sunscreen on the bottle. That way you’ll know when to throw it out.
        You also can look for visible signs that the sunscreen may no longer be good. Any obvious changes in the color or consistency of the product mean it’s time to purchase a new bottle. “

  5. #1 – you did say BAKE! #2 – I had no idea they made an SPF 100! #3 – LOVE your title! I’ve had 3 pre-cancerous things cut of of me thanks to my teen years. I am like your boyfriend! Even though it says so many hours, I re-apply almost every hour or two! 😛

    Actually, I’ve always wondered about expiration dates too…

  6. Sarah Beane says:

    Really good article! People should be more aware of sun protection but the range of different SPF’s is mind boggling and confusing.

  7. gracesbeauty says:

    This was an eye opener for me; I thought my BB cream was enough. Now I’m going to invest in a big floppy hat and a good cover up, thanks for referring me to this article. 🙂

  8. Casey, Thank for stopping by and commenting on our blog post and for linking back to this great post. Thank you for getting the word out. I saw an awful photo in a medical journal recently of a 60 some year old truck driver. The left side of his face looked like he was in his 90’s drooped and wrinkled such was the damage from the sun. The right side like some one in the 60s. It was a great PSA for keeping out of the sun.


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