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Terephthalylidene Dicamphor Sulfonic Acid

What Terephthalylidene Dicamphor Sulfonic Acid is & what it does

A water-soluble UVA filter (Mexoryl SX / ecamsule) that is photostable and targets shorter UVA wavelengths. It is often combined with avobenzone and Mexoryl XL to broaden and stabilize UVA coverage.

What is Terephthalylidene Dicamphor Sulfonic Acid and what does it do in sunscreen?

Terephthalylidene Dicamphor Sulfonic Acid is a water-soluble UVA sunscreen filter, sold under the trade names Mexoryl SX and ecamsule. It absorbs UVA light, especially the shorter UVA wavelengths most linked to photoaging and pigmentation. It is photostable, meaning it does not break down quickly in sunlight.

Is Terephthalylidene Dicamphor Sulfonic Acid a UVA or UVB filter?

It is a UVA filter. It targets the shorter end of the UVA range, so sunscreens combine it with UVB filters and broader UVA filters such as avobenzone or Mexoryl XL to reach full broad-spectrum coverage. Pairing it this way both broadens and stabilizes the UVA protection.

Is Terephthalylidene Dicamphor Sulfonic Acid safe?

It is regarded as a well-tolerated, low-irritation filter. It is photostable and, being a large water-soluble molecule, shows very low skin penetration. It is approved for sunscreens in the EU, UK, Canada and many other markets, and it also has a specific US approval, which is unusual for a modern filter.

Does Terephthalylidene Dicamphor Sulfonic Acid clog pores?

Generally no. It is a water-soluble filter rather than a heavy oil, and it is not flagged as comedogenic. If a sunscreen breaks you out, the oils, waxes or other emollients in the formula are far more likely the cause.

What else is Terephthalylidene Dicamphor Sulfonic Acid called?

On the label it appears under its INCI name, Terephthalylidene Dicamphor Sulfonic Acid. It is far better known by its trade names, Mexoryl SX and ecamsule. All three refer to the same UVA filter.

Is Terephthalylidene Dicamphor Sulfonic Acid natural?

No, it is a modern synthetic UV filter made in a lab and not found in nature. Synthetic here simply means it was engineered for stable, targeted UVA protection, not that it is unsafe.

Sunscreens with Terephthalylidene Dicamphor Sulfonic Acid

We rate 284 sunscreens that contain it, showing the top 10 by overall score:

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