Purito Centella Unscented Sun tests as SPF 19 in two different European labs
Update (22nd of December 2020): We would like to share a few updates since our original article:
- You can find the official response from Purito here: https://www.instagram.com/p/CIYZVYvHnfw/
- Purito has suspended the sales of all three of their sunscreens: PURITO Centella Green Level Unscented Sun, PURITO Centella Green Level Safe Sun, and PURITO Comfy Water Sun Block
- The sales of Klair's Soft Airy UV Essence sunscreen is also suspended as it is manufactured at the same place as the Purito one and has a similar formula
- There is now also another independent test of the PURITO Centella Green Level Unscented Sun done by the Korea Institute of Dermatological Sciences that measured an SPF of 28.4 (source here: https://www.instagram.com/p/CI5zU-xnWHX/)
- We have a few more useful information in our Instagram stories adding more context to false SPF claims and SPF testing: https://www.instagram.com/stories/highlights/18060805732248840/
I suspect this will spark further discussion and controversy, and to be honest, I am worried of what might come, as I realise the sunscreen in question is a super popular and well-loved product.
But I also see a huge discussion ongoing between the “sceptics” and the “believers” about a question that should not be decided by reasoning, or worse, beliefs, but what is, at the end of the day, a measurable fact.
As a cosmetic formulator & entrepreneur, I have started a sunscreen project for a little more than a year ago with the help of one of the top sunscreen formulators in Europe.
I wanted (or rather still want :)) a light, cosmetically elegant sunscreen for every day that uses modern sun filters such as Uvinul A, T and Tinosorb S. Of course, I considered the examples of the popular, super-elegant feeling Korean sunscreens, one of them being the Purito Centella Unscented Sun.
Looking at the formula, and seeing only two filters, I raised my eyebrows even before I learnt that Purito disclosed the unusually low filter amounts (3% Uvinul A and 2% Uvinul T) and that the SPF 50+ is SPF 84.5 according to the brand.
When one of our awesome users submitted the filter % claims to INCIDecoder I went to the BASF calculator and put in the numbers. It is a tool for rough estimations and it is well-known among formulators to be on the “conservative side”. Still, the estimation of SPF 10.3 from the BASF calculator vs the SPF 84 claimed by the brand sounded strange.
Having doubts, I asked our sunscreen formulator’s opinion specifically on the Purito Centella Unscented Sun and how he thinks it might be possible to achieve SPF 50+ with these two filters at these low amounts.
He answered me pointing to false SPF ratings in the past, essentially saying that it is highly doubtful that the SPF claim on the Purito product is realistic.
This was the point when I knew that we have to send the product for testing to European labs. Testing takes time and effort, so all this happened during the summer when I ordered several bottles of Purito (they arrived with an expiry date of 14 June 2023).
We decanted the products to mask the true identity and to avoid any prejudice bias in the lab and sent in the samples for the SPF testing.
As the quickest and most cost-effective option, we started with an in-vitro test in the Polish lab Ita-Test. It came back as SPF 15.8 with standard deviation of 2.3, with UVA-PF 9.1 ± 1. Click here for the full report >>
In vitro testing is still only an estimation, and is not the measurement required to put the SPF value on the final product. So we went on to order the 10 person in-vivo test according to the ISO 24444 standard needed in Europe to put an SPF claim on the bottle. The results came back five weeks later. The mean SPF was 19. Click here for the full report >>
Being a sceptic, and reading about potential reproducibility issues of SPF measurements, I wanted to have another fully independent measurement from another lab, even from another country. Our sunscreen formulator recommended a well-respected German lab. The cost of testing in Germany is multiple times that of the Polish tests, and the German lab offers a screening in-vivo test with 5 persons that can later be extended to the full study if the SPF value is what you expected. As this second in-vivo test is a “double-check test” on our part, we opted for the cost effective screening test. It came back as SPF 19.2 ± 2.4. Click here for the results from the lab >>
Would the measurements come back the same from another batch or from another lab? I am not sure. Would it come back as SPF 84 or anywhere close to it? At this point, it seems highly unlikely.
I hope publishing these results is enough to raise concern and others will also send the product to independent lab-testing (maybe along with a few other sunscreens).
posted on the 3rd of December, 2020