5 sticky myths about sunscreen


Who says “summer” says “sun.” And who says “sun” says “suntanning” … or “cancer“. 

I don’t think anyone should freak out over exposure to the sun. On the other hand, if you’re gonna use sunscreen, you might as well use it properly.

After all, this is not just about cancer: UVA rays cause premature aging of the skin, while UVB cause those infuriating sunburns.

At the pharmacy, people very seldom ask me for advice when it comes time to sunscreens. I wonder what determines their choice. A nice bottle with a cute doggy on it? Statements like “Ultimate Protection Apocalyptic 3000”? Low (or high) price tag?

Here’s the truth: choosing the best sunscreen is FAR from easy, even for me. It’s not easy to use it well either.

In this comic, I address 5 beliefs about sun exposure and sunscreen that I hear all the time.

In a second comic, I’ll address the issue of allegedly toxic ingredients in sunscreen (such as nanoparticles and endocrine disruptors), vitamin D deficiency and the belief that sunscreen is more carcinogenic than the sun itself.

P.S. There’s a joke that is a direct homage to the Simpsons. Who’s gonna find it first?

Translation by Olivier Bernard, proofreading by Lauren Knight.



Sunburns and skin phototype



Shade and UV rays



About sun protection factor SPF



Amount and frequency for applying sunscreen



Bad marketing about sunscreens

How to choose a sunscreen



Conclusion and radioactive white




25 responses to “5 sticky myths about sunscreen

  1. Actually, the first myth isn’t so much of a myth. If you look at the incidence of skin cancers, the way we epidemiologists track frequency of new cases of a disease in an at risk population, you will see that it is VERY low for essentially all races except Caucasian. There’s a reason for that. Melanin in the skin is a regional adaptation to relative length of sun exposure at each latitude. Melanin protects the skin from UV light.

    Now, onto another hat I wear: Physician. Clinically, we rarely see cancers (this is something called prevalence) or precancerous lesions in any race or ethnicity besides those with pure Caucasian ancestry. I refer you back to the explanation above for the reason for this.

    • thepharmafist

      Thanks for the precisions!
      In my practice, I see this belief mostly in people with phototype 3 who, for some reason, don’t burn easily. They tend to think they don’t need sunscreen for that reason.

      • I forgot to mention: Incidence of skin cancer is positively correlated with sunscreen use. Yes, you read that right, sunscreen use and skin cancer are POSITIVELY correlated. No one knows why, as it seems counter intuitive. But it goes to show that this is one of those things that are a lot more complicated than we try to make it.

        • True, here’s the study about that:

          But we do actually have an explanation for this positive correlation:
          “[Results] substantiate the hypothesis that sunscreen use, by permitting more time sunbathing, is associated with melanoma occurrence.”

          So it’s not the sunscreen itself, but rather a careless attitude and longer exposition to UV rays that would likely explain the increased rates of skin cancer.


          • That’s merely a hypothesis. I could postulate several possibilities. The way things tend to work, it’s probably a combination of things. We know from the medical condition called xeroderma pigmentosum that ANY amount of UV light exposure causes skin cancer. In between all the other factors regarding “normal” skin and skin cancer are a multitude of factors. It’s not a parsimonious issue, no matter how much we’d like it to be.

  2. You know, i use korean sunscreen last year, and is not sticky (actually gets dry as if you hadn’t apply nothing but regular cream), all are 30+ uva and uvb, have nice and sotf smells, and i can buy them by web ^O^

    I’ve a skin color like “dead corpse white Nº 5” xD so i MUST use sunscreen since early spring, so using the regular ones, like banana boat or others, made me feel like a sticky paper to catch flies x___X

    But korean and japanese sunscreens save my life xD and changed my relationship withs the sun from “absolute hate” to “meh” xD

    I buy them online and, oh koreans are smart, they sell you samples first so you can actually try the product, before buying the big bottle

    This year i’m going to buy a lot of them: i live in Chile, and with de ozone stuff, we have UV levels above the scale (the scale come from 1 to 11, where 9-11 is “just DON’T get out”… and last year we’ve levels like… 14 or more X____x)

    Oh, and korean susncreen is not expensive, and some girls have nice and pretty blogs where they give you a nice review of a lot of those products ^^

    And, sorry by my english xD<

    Oh, and nice work!!!

    • thepharmafist

      Thanks for sharing your experience!

      SPF 30 and broad spectrum (UVA+UVB) sounds legit.

      And yet, it’s all about the ingredients. Brands, packaging, texture and such should not be taken into account to assess the quality of a sunscreen. Even my personal brand of sunscreen makes crappy versions of their products.

      It’s great that you’ve become used to sunscreen! For a lot of people, that’s the toughest part.

      Thanks again !


  3. So I suppose the sun screens could have also been called Duff / Duff Lite and Duff Dry?

  4. From what you say, doubling the index seems to divide by two the amount of UVs reaching your skin. If it is already 2%, then it reduces only to 1%, which is not much an effect. This seems to be simply due to the fact that light absorption through the sunscreen follows an exponential decay, like I(skin) = I0 * exp(-d*alpha), where I(skin) is the amount of UVs reaching your skin through the sunscreen, I0 is the amount of UVs hitting the sunscreen, d is the thickness of sunscreen and alpha is the absorption coefficient. So it seems that in the equation, the index is simply proportional to the absorption coefficient (or IS the absorption coefficient, with customized units). So this would also mean that doubling the index allows you to divide by two the thickness of sunscreen for the same effect ( except you would put less grease on yourself). If this is true, why say that an index over 30 is useless, and why say that there is only one single amount of sunscreen we should use ? If I am correct, it is useless to increase the index of 30 precisely because you decide of a fixed amount of sunscreen you have to use that is so huge.

    • Mathematically, that makes sense. However, practically, it does not, because you can’t spread a tiny amount of sunscreen over a huge surface. Sunscreens are notoriously hard to apply evenly.
      There’s an “ideal” amount of it that should be used to obtain the announced SPF. You could definitely reduce that amount with a higher SPF… but not infinitely.
      Thanks for your input!

  5. Fascinating read, Olivier! Cleverly illustrated as always.

    Personally, I use a mineral sunscreen (6.5% titanium dioxide; 6.3% zinc oxide) and have been extremely satisfied so far. No sunburn at all!

  6. This makes sense and does answer my comment.

    Thanks for your reply!

  7. Since you’ve asked for typos to be identified, I think the last sentence before the CONCLUSION box needs a “not”, as in “As you can see, . . . should NOT have a influence on your decision.” Unless you really think logos and vague statements should.

  8. Hi,
    Love your site and appreciate the great info, but I feel you’ve missed an important factor on the sun screen issue. Clothing is the most natural and cheapest sun screen that exists. Covering up (long sleeves, scarves, hats) is what people in other parts of the world have always done. It’s free and doesn’t contaminate the environment!

  9. Homer went to the brewery and three types of Duff were all coming out of the same giant pipe. Thanks for writing this article and especially for including the Simpsons reference. Good stuff!

  10. So when products offer longer hours of protection, say 8hrs. They are being misleading? There’s quite a few that do this now.

    • thepharmafist

      Hi Joe !

      This is most likely based on the companies’ in-house tests, which may be reliable or not. Because we don’t have a way of knowing, the recommendation for “every 2 hours” is the most conservative one.

      That being said, many dermatologists will tell their patients that one application a day is enough, because they’re concerned that recommending too many applications will discourage people from using sunscreen altogether.

      Thanks for the question!


  11. What about sunscreens that claim to give all day protection ? How realistic is this?

    • Hi !

      It could be true. Sunscreen companies do their own in-house tests and don’t share those with the scientific community, so it’s hard to differentiate what is marketing and what is science.

      Because of that, I think that the 2-hour rule should still be followed to obtain the best possible protection.

      Thanks for your question !


Write your comments here (I have to manually approve them before they show)