Ingredient glossary
Mexoryl SX
On your shelf ✓What Mexoryl SX does for your skin, who it suits, and what to watch for.
INCI: Ecamsule
In short: Mexoryl SX delivers uva protection, suits most skin types, and the evidence behind it is strong.
- What it does
- Uva protection
- Best for
- Most skin types
- Evidence
- Strong
- How long
- Straight away
how it was measured
Measured on UVA attenuation by the applied film, read as UVA protection factor / PPD; the clinical consensus; no trial pins the point.
The molecule
The Glow take
Only as good as the sunscreen it lives in.
As a single filter, Mexoryl SX only matters as part of a finished sunscreen you actually reapply. The best SPF is the one that feels good enough to wear every morning.
— Maya
What it does
- uva protection
strong evidenceClinical sunscreen trials and regulatory data show Mexoryl SX maintains high UVA absorbance with minimal degradation and improves UVA protection indices in…
Why we say this
- Clinical sunscreen trials and regulatory data show Mexoryl SX maintains high UVA absorbance with minimal degradation and improves UVA protection indices in finished products.
On a label: usually effective at 3-10%.
The UV filter family, at a glance
5 UV filter entries in the base, Mexoryl SX among them. 3 of the 5 are a supporting active.
Who it's for, and who should skip it
Tends to suit
- all
Approach with care
No specific group flagged to avoid it.
- Clogs poresLow
- Irritation riskLow
How it fits each skin type
- DrySuits
- CombinationSuits
- OilySuits
- SensitiveSuits
Where it fits in your routine
This one works on contact — there is nothing to wait for.
What that covers, and what it does not
- Measured on: UVA attenuation by the applied film, read as UVA protection factor / PPD.
- The protection is optical: a sulfonated camphor filter absorbs UVA as soon as the applied film has dried, and there is nothing in the skin to remodel.
- This is not read off absorbance alone - standardised human testing measures it, with the panel irradiated roughly 15-30 minutes after application, and that interval is the whole of the wait.
- Two limits the bucket does not carry on its own: the film is the protection, so it goes with water, towelling, sweat and time, which is why reapplication exists and why the result is maintained rather than accumulated; and the photoageing benefit of daily use over years is a separate and far slower outcome from the protection timed here.
- 'Persistent UVA protection' in the marketing means photostable across one exposure, not building up over visits.
ISO 24442 (in vivo UVA protection, PPD) and ISO 24443 (in vitro UVA), which fix the application-to-irradiation interval; EU Cosmetics Regulation Annex VI entry for terephthalylidene dicamphor sulfonic acid (ecamsule). No PMID claimed.
Light, and how to keep it
Mexoryl SX does not break down in light, which is worth saying because plenty of people assume it does.
how it was measured
Mexoryl, a novel ultraviolet A filter, provides efficient ultraviolet A coverage, better photostability, and enhanced water resistance.PMID 17805138 · abstract
measured stable in light
Where this filter sits on the ladder of what fails first in an ageing sunscreen: does sunscreen expire?
What regulators say
In the EU mexoryl SX is capped at 10% (as acid) as a UV filter (Annex VI entry 7).
What the regulator says, in full
- A UV filter has no dose-effect relationship worth stating for one ingredient: the number a reader can use is the product's SPF and UVA rating, measured on the finished film by ISO 24444 and ISO 24443, and it depends on the whole filter system, the film thickness and the vehicle, not on the percentage of ecamsule alone.
- The regulators set ceilings for safety, not efficacy: EU Annex VI entry 17, 10% as the acid; not in the US sunscreen monograph; it reached the US market only inside specific approved products.
- Above those limits nothing is permitted and below them the SPF is whatever the product's own test says.
- The caveat: it covers UVA only, so its percentage says nothing about SPF.
Plays well with
- uv filters
- antioxidants
Mexoryl SX, answered
Is Mexoryl SX safe during pregnancy?
Yes. Mexoryl SX is considered safe to use during pregnancy and breastfeeding. As with anything, if you are unsure it is worth a quick word with your doctor or midwife.
Who should avoid Mexoryl SX?
No specific group is flagged to avoid Mexoryl SX. It is well tolerated by most skin. Still, introduce anything new one product at a time.
What concentration of Mexoryl SX actually works?
Mexoryl SX tends to do its job in the 3 to 10% range. Much lower and it is likely underdosed.
Does Mexoryl SX break down in the light?
No, and it is worth saying because plenty of people assume it does. Mexoryl, a novel ultraviolet A filter, provides efficient ultraviolet A coverage, better photostability, and enhanced water resistance.
Compare Mexoryl SX with
2 comparisons built.
This, for every label you own
One ingredient is easy. A full label is where it gets confusing. The Ingredient Decoder reads any product and tells you the honest truth, ingredient by ingredient.
Sources & how we reviewed this
What changed on this page
- : the effective dose from trials, what the EU regulates, the highest dose tested
- : light stability
- : what the EU regulates