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Third-Party Sunscreen Testings: Some Thoughts

Many readers and followers have been asking for my opinion surrounding third-party sunscreen testings. I’ve written about this very briefly in replies on Twitter and Instagram before but here’s my full-length blog post on it.

Third-party sunscreen testings have their place but I think they need to be closely examined with a sceptical mind to determine whether each claim has merit. Not disbelief but a rejection of judgment until sufficient evidence is examined.

This sort of DIY test (i.e., apply random sunscreens on the back then lay in the sun for a few hours) is next to pointless. (Image Source: Weibo)

Different UV test methods will give vastly different results. Sunscreens are sometimes falsely accused of not meeting labelled claims due to flawed testing methodologies. For example, Japan requires in vivo ISO 24444 (SPF) & ISO 24442 (UVA) test methods for all products with sun protection. In other words, they’re tested on humans. Most third-party tests opt for in vitro tests, which are done on plates because they’re much cheaper and faster. According to many peer-reviewed studies, however, their results are unreliable due to a lack of repeatability and correlation between the in vitro and in vivo data. Test the same sunscreen 10 times, and you’ll get 10 vastly different results.

It’s also very common for major brands to have regional products and formulas. Shiseido sunscreens sold in the US, Europe, and Asia, for example, all contain different ingredients (resulting in different UV protection) but have the same packaging, and near-identical product names. I often come across Chinese third-party online testing (and subsequently failing) sunscreens that are clearly made in China for the local Chinese market but will still list Japan as the product’s country of origin.

Another thing to consider is just because a third party decided to take it upon themselves to test sunscreens, doesn’t mean they’re automatically more trustworthy or reliable.

Consumer Reports test sunscreens in the US but their evaluations are completely based on their own made-up methodology which for SPF testing involves applying sunscreens to backs and then soak in a tub of water before exposing the areas to UV light. This is not how SPF testing is done. It could be argued that CR is simply replicating what could happen in real life (e.g. swimming) but skewing a testing procedure — especially an established one — to achieve a specific test result is terrible science.

There has been a huge push in China in recent years to grow and expand its cosmetic industry. Creating a cloud of mistrust surrounding existing popular brands while proclaiming the Chinese government has the strictest standards when it comes to sunscreens may encourage their own citizens to try Chinese brands (and dissuade people from buying products from countries with economic or political conflict).

Insuk Ahn from the Korea Institute of Dermatological Sciences seems reliable, but she is clearly working with Korean brands regarding all her tests and findings because the country has a lot at stake on a global scale. (The South Korean government is well-known to play a big role in supporting the major players in the cosmetic industry because it helps with the country’s soft power.) Taking South Korea’s very strict defamation law and her position (and experience) in the industry into account, I find it very difficult to believe that she’s impartial or completely truthful.

Issues like how the third party obtained the sunscreen sample and how was it stored come into question as well. I find the sunscreen choices in a few third-party tests I came across peculiar since numerous products shown have been discontinued or repackaged for a couple of years already. Mixing fresh and very old testing samples will obviously skew results.

Which sunscreen is “best” or “most protective” is quite a personal thing — your skin type, how your skin reacts to UV, where you live, your climate, and your activities all come into play. A sunscreen’s overall formula (and how it feels on the skin) matters just as much as the UVA/UVB rating. It’s a moot point whether sunscreen has superior UV protection or not if it’s heavy, greasy, or unpleasant. The best sunscreen is the one that you’ll actually use correctly and generously daily — whatever that may be.

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17 Comments on Third-Party Sunscreen Testings: Some Thoughts

  1. Hi, excellent comment. I find it very difficult to rely on any third party reviews precisely for the reason you mentioned – they are often influenced by motives fr removed from impartiality. For that matter honest consumer reviews are a lot more reliable, although recently there has been an influx of fake reviews on all sites, including Amazon. Thank you for your blog ang your site, as I said in one of my previous messages I often refer to your descriptions when I want to buy a Japanese product. You deserve more recognition

    • Thank you for your kind words.

      Yes, I agree. I feel that reviews from those that have the same skin type, personal preferences, and living in the same climate as you would be far more helpful and relevant than any third-party testings.

  2. Could you please answer this random question? Is 3300円 a reasonable price to ship a 1200円, 100-page book (mook) from amazon jp to the US (i.e. 1200円 + 2200円 配送料)? The book is no longer in-print; I can only find another copy on mercari jp, and the total cost to ship is >4000円 by most proxies.

    • Amazon Japan ships internationally via DHL express, expensive but extremely fast and reliable. Books tend to be heavy and therefore expensive to ship.

      Generally speaking, the more items you buy, the less shipping works out to be overall since the rate is calculated per kg. This is especially true if the other items are small and very lightweight. You’ll often find that shipping just increases by 100-200JPY for each additional item you add.

      • Thank you for your insight. Can I borrow your mercari account instead? I promise it’s G-rated material. 😀

  3. Is there an official lab or organization in Japan that requires sunscreen manufacturers for UV testing before they are released into the market? Or do they also accept test results from other approved labs?

  4. Thank you…all the sunscreen tests on social media are exhausting. It’s like a fancier version of when people used to plug active ingredients into the BASF sunscreen simulator to estimate protection. And it’s scummy that organizations are jumping on this trend for their own gain.

    I think the best way to decide on a sunscreen is to read unbiased reviews (to make sure it’s not universally panned) and try it yourself and judge the performance. There’s sadly not an easier or fool proof way to find out whether it will work

    • Any content about how many sunscreens on the market are supposedly “failing to meet SPF claims” is guaranteed to generate a large amount of traffic and therefore revenue. I’ve seen a few articles in Taiwan that clearly used BASF sunscreen simulator (their results are copy/pasted).

      There is a way and that is by reading the package carefully and actually following the manufacturer’s advice/directions! Most people don’t bother to do either.

      • Well it is possible for some products to be shitty and not live up to their promises like a product claiming to be sebum resistant not actually being the case in reality. That’s where reading reviews and trying it yourself comes into place.

        But yes, reading the package and following instructions is definitely very important lol and should be a given…

  5. I completely resonate with the last paragraph. What’s the point of having a super-protective sunscreen that’s too greasy or tacky for everyday wear? Thank you for the post!

    • I often hear people say that they don’t care that if sunscreen feels greasy as long as it’s highly protective. They, however, forget (or don’t realise) that sunscreen also needs to stay put on the skin in order to be protective. If it’s sliding around or it’s transferring off, they’re not going to get anywhere close to the labelled protection.

  6. How do you determine whether a sunscreen is good for an outdoor hike? Are the Kose Suncut Perfect Gel or Essence sunscreens only for indoor use?

    • By reading the packaging. Sunscreens that are formulated for the outdoors/sports are explicitly stated on the packaging (in Japanese of course). No guessing or detective work necessary.

  7. Hi G,

    Thanks for this. Just wanted to check if KOKORO is still a good online option for Japanese products? I don’t want to go back to YesStyle now after seeing your post that it might be other formulas. I want the Japanese formulas (spfs specifically)

    Thanks again.

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