How to read a sunscreen lab report
If a brand shows you a report, here is how to tell whether it says what they claim it says.
In October 2025 independent testing of several best-selling sunscreens in India returned results below their labelled SPF, and the coverage that followed left a lot of buyers asking a fair question: how would I ever know? A report is the answer, but only if you can read it. Here is what to look at.
1. In vivo or in vitro
In-vivo testing (ISO 24444) is run on human skin. In-vitro testing is run on a plate. In-vitro is faster and cheaper, and it is what a lot of published comparisons use. For an SPF number on a pack, in-vivo is the meaningful one, and it is the method the Indian standard IS 17494:2025 adopts. If a report does not say which method it used, that is the first question to ask.
2. Which batch
A result belongs to the batch that was tested, not to the brand and not to the product line forever. Formulations get remade; a claim that was true for one production run is not automatically true for the next. A report without a batch code cannot be matched to the tube in your hand.
3. Which lab, and is it accredited
Look for the testing laboratory's name and its accreditation. An unnamed lab is not a citation.
4. The date
A test from years ago describes the formula as it was then. Pair the date with the batch.
5. Whether it is signed, and complete
A screenshot of a number is not a report. The document should be the lab's own, signed, with its method and conditions stated — including the application density, which should be 2 mg/cm².
What we do with ours
Each production batch goes for in-vivo testing, and the signed report is published against that batch code on our proof page — lab, date, method and measured value. Our first production batch is in testing now, and until that report exists the proof page says exactly that instead of showing a number. A result we do not like gets published too. That is the only version of this that means anything.
