Tuesday, November 8th, 2011

By Nicki Zevola, Pennsylvania, Skincare Expert

Nicki Zevola is a beauty expert and the founder of FutureDerm.com, where she provides clear, well-researched information about beauty+skincare, fashion+style, nutrition+fitness, and personal development from a different perspective from most in the blogosphere. Named one of the top beauty bloggers since 2009, Nicki is also a medical student (M.D.) with an estimated graduation date of May 2013. Continue reading her full bio

5 Surprising Skincare Facts You Didn’t Know (Until Now!)

1. Mixing certain skin care ingredients inactivates them.

Even if you hated science classes, you have to keep in mind that skin care is the product of somewhat advanced chemistry, subject to pH imbalance, unexpected reactions, and the like. For instance, many cosmetic chemists do not recommend using products with alpha hydroxy acids, like glycolic acid, and retinol together. This is because retinol is most active at a pH of 5.5-6.0 (Journal of Investigative Dermatology), while glycolic acid has an optimized pH at 3.83 (Cosmetic Dermatology). Another problem is using a heavier skin care product under a lighter one. High concentrations of certain occlusive agents like petrolatum and mineral oil prevent the ingredients in the lighter serum from reaching your skin as effectively. Most dermatologists thereby recommend applying the lighter product first.

2. You should never apply self-tanner before going out into the sun, unless you use a sunscreen first.

Most self-tanners work by using dihydroxyacetone (DHA) as the main ingredient. According to a 2007 study published in Germany, DHA causes the skin to release 180% more free radicals once exposed to the sun. Therefore sun protection is extremely important when you have used self-tanners containing DHA within the past 24 hours.

3. There is no such thing as 100% SPF protection from a sunscreen.

According to dermatologist Dr. Rachel Herschenfeld, M.D., the percentage of protection you get is 100 – (1/SPF number)*100. I know that looks complicated, but let’s take SPF 30 for example:

Percentage of protection = 100 – (1/SPF number)*100
Percentage of protection = 100 – (1/30)*100 = 100 – 3.3
Percentage of protection = 96.6

Using that same principle, SPF 50 provides only 98% protection, and SPF 100 provides 99.9%!  Keep in mind this is the amount of protection provided when you apply a whole shot-glass full of sunscreen for your entire body and reapply religiously every 2-3 hours. As such, it’s safe to say there is no such thing as 100% sun protection from a sunscreen.

Check out two more facts you didn’t know! 

4. Try to avoid apricot scrub.

Apricot granules tend to have rough, almost triangular, edges. When apricot scrub is applied roughly, it can actually rip or stretch the pores. For this reason, it is best to stick with dermatologist-administered microdermabrasion or a different scrub, like my personal favorite, NIA 24 Physical Cleansing Scrub.

5. “Hypoallergenic” doesn’t mean anything.

“Hypoallergenic” by the dictionary definition means “below normal” or “slightly” allergenic, but there is no standard in any country that provides an official certification process that a skin care product or cosmetic must undergo before being labeled as hypoallergenic. While most companies would never release a product with a high risk of allergy as “hypoallergenic”, it is still possible for the rare individual to have a reaction. I’ve fallen victim to getting hives from chamomile, limonene, and several other extracts on products marked as “hypoallergenic.” So trust your own knowledge!

Bottom Line

Within the past twenty years, dermatological science has made incredible strides in developing ingredients and products to make a dramatic difference on your skin. Ingredients like retinoids, alpha hydroxy acids, antioxidants, niacinamide, and peptides all help us have clearer, brighter skin – and for many more years of life than previously thought possible. As we move from the tween to the teen years of the 21st century, I’m anticipating even more sensational breakouts in the skin care industry! For now, though, it is important to keep in mind that not all claims are created equal, and that it is just as vital to check a scientific or medical journal as the label when it comes to knowing what is really going on with your skin care!

Discussion and debate are highly encouraged, and we expect community members to participate respectfully. When asking a question, please check the FAQ section (above) for information about purchasing, price, dupes, and the like. If you have general feedback or need technical support, please contact us.

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47 thoughts on “5 Surprising Skincare Facts You Didn’t Know (Until Now!)

  1. Caroline F.

    Love this info

  2. I didn’t know you can get SPF100. Great article

    • Neutrogena Ultra Sheer Dry-Touch Sunblock comes in SPF 100. 😉

      • Smidgeroo

        There isn’t any location in the world with enough sun to warrant SPF 100. The number indicates time it’s effective, not necessarily the amount of protection. Even SPF as low as 30 can provide very good full protection when reapplied, which all sunscreens should be.

      • Lisa

        SPF 100 is not the same as 100% SPF protection.

      • Lucy

        So then it’s only 99% protection when applied properly. Still not bad 😉

    • CeeBee

      I think the thing to remember is that the SPF number doesn’t correlate directly to the length of time you can stay protected while out in the sun – you still need to reapply it regularly, as Nicki states, regardless of the SPF.
      In my opinion, the difference between SPF 50 and 100 is pretty much negligible – there’s only slight difference in the level of protection it provides (and personally I think there should be more info on whether the ingredients block either UVA or UVB only (both preferably!) as well) – it does not mean that one is twice is good (or worth twice as much $$$) as the other or that you can apply SPF 100 and then forget about it for the rest of the day.

  3. Laura R

    excellent pointers- thank you, Nicki! correct me if i’m wrong, but isn’t “non-comedogenic” also an undefined term? i know it means that the product doesn’t clog pores, but that is not a proven claim usually, and anything you put on your face whether makeup or moisturizer will clog pores at least temporarily….

  4. Very informative article Nicki!

  5. Leticia Centeno

    Really liked this post!


  6. Saffy

    Great post!

  7. Dina

    Thanks for such an informative and well written post. I’d love to read skincare tips on Temptalia on a much more regular basis.

    Bravo Nicki.

  8. @Laura – You’re absolutely right. “Non-comedogenic” does not mean that a product has to meet any specific standards for clogging the pores.

  9. Thanks for the info! Very helpful!

    Kindness is the best accessory,

  10. Thanks for this piece. Great info in a couple quick paragraphs. Thank you!

  11. Alison

    Is there a list somewhere of PHs of common skincare ingredients? I’d love to check to make sure my routine isn’t sabotaging itself!

  12. Kary

    This was great! Good job, Nicki! :)

  13. niche

    This is a great post. I knew some things but you definitely explained it better! I hope there will be more posts as I did learn a lot. I love numbers so the SPF thing is very cool.

  14. Great post but I’m not surprised, I knew most of those already. Then again I’m adamant about my skincare and make sure I know these things. Still – this is considerably better than a typical magazine article about skincare! Thanks for sharing.

  15. jagoda

    knew all these haha

  16. Shirry

    Quite informative. Thanks,

  17. yvette

    I have a question I’d LOVE answered. What’s the best way to treat post inflammatory hyperpigmentation? I am fair skinned and get red marks after pimples (even when I don’t touch them) that last for so long – like a year or more. My right cheek is covered with them. How can I avoid this? Even though my active acne has calmed down, I’m stuck with bad looking skin.

    • Smidgeroo

      Use at least SPF 30 all day in the area, as sunlight makes you produce melanin and will keep the marks from fading. At night, use a fading cream. Hydroquinone has been the gold standard for years, and I like Proactiv’s Skin Lightening Lotion. Pair it with a Salicylic Acid 1% or 2% moisturizer/lotion (any higher will just irritate the skin and do more harm than good) which will accelerate proper exfoliation. To sum it up: SPF during daylight hours (even short trips on overcast days) and active fading lotions at night.

  18. Great article Nicki! :]

  19. i absolutely love this article. as a prospective MD student myself, i appreciate it when i can hear the facts! this is information i have never encountered before. thanks nicki!

  20. T

    Okay did NOT know about the self-tanning active ingredient causing my skin to release free radicals! I self-tan so I don’t have to go in the sun! Ugh. Everything is bad for you, haha.

  21. Gina

    That’s really good to know about putting on heavier products after lighter ones! I always put my moisturizer on last anyway (meaning serums always go before it) but it’s still a really good piece of information to keep in mind.

  22. Liz

    Love your blog, love this info, great work Nicki!

  23. Traci

    I only have one NIA 24 product (a sunscreen) and I absolutely love it! It’s sometimes hard for me to find face products without dimethicone. I would love to hear more about these products!

  24. Katie

    Smart girl! Fantastic article, thanks!

  25. Being a medical student, you do know that there are a lot of studies that show that the SPF may do more harm then good, right?
    I’m not saying to not use it when you go to the beach, but using it all the time makes a sort of negative feed back and the cells don’t produce the melanin they normally should.

    • alex

      I’ve read about studies like these also. I’ve also heard that it’s bad to use SFP 35 and up. Does anyone know more about this?
      I agree that sunscreen is necessary sometimes, but I think that companies hype up things and lead people wrong.

      • sara

        I agree with both of you on this one. This article is incomplete to me. There was much more depth or knowledge that could have been included in this post. Even explaining how many of the sunscreen formulations do not protect both types of sun rays equally or explaining what ingredients to look for would have helped. A bit disappointed.

  26. Coco

    This post was super helpful! I had no idea self-tanners release that much more free radicals once you’re in the sun! Just to be sure, you’re supposed to put sunscreen UNDER the self-tanner right? (Not over? – Or does it not matter lol!?) Thanks so much for the info :]]

  27. Great post! Now I have like 50 questions I want personally answered! LOL 😛 Love this though – Good, common-sense information :)

  28. Amanda

    this was a great post! especially about mixing products, so so helpful to know!

  29. my

    Thanks for these infos! :)

  30. More of this kind of info please!!! 😀

  31. I wouldn’t want 100% sun protection. I need my vitamin D! Interesting about the apricot scrub – there are a lot of them in the shops too. I know I’ll be avoiding them from now on. Thanks

  32. Sarah Cormier

    Excellent Article Nicki! Very informative!

  33. Jessica Peng

    this is sooo helpful. Thanks!

  34. Cat

    I don’t get the part about applying the lighter product first. So would I use my serum first or my night cream first?

  35. Wow! Didn’t know any of them. Number five was especially helpfull. Now I know not to buy a product just because it is “hypoallergenic.”

  36. KD

    Not sure if you’re still checking comments but in case you are I had a question. When you say glycolic acid and retinol cant be mixed, do you mean I shouldnt use one right after the other (for example both at night), or that if I’m using one in any part of my routine, it is useless to include the other?
    Basically, could I use glycolic acid in the morning and retinol at night?