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Diethylhexyl Syringylidenemalonate

What Diethylhexyl Syringylidenemalonate is & what it does

An oil-soluble antioxidant (Oxynex ST) that protects formulas from oxidation and helps stabilize UV filters, supporting durable sun protection. It also defends skin from free radicals.

What is Diethylhexyl Syringylidenemalonate and what does it do in sunscreen?

It is an oil-soluble antioxidant, often sold under the trade name Oxynex ST. In a sunscreen its main job is to protect the formula from oxidation and to help keep the UV filters stable, which supports more durable sun protection over time. It also helps defend skin from free radicals generated by sun exposure.

Is Diethylhexyl Syringylidenemalonate safe?

Yes, it is regarded as a safe, well tolerated antioxidant at the levels used in cosmetics. It works mainly within the formula, helping to keep oils and filters from breaking down, and it is not associated with common irritation. Acne-prone or sensitive users generally tolerate it without issue.

Does Diethylhexyl Syringylidenemalonate clog pores?

Generally no. It is used in very small amounts as a formula stabilizer rather than as a rich emollient, so it is not a typical pore-clogging ingredient. If a product breaks you out, the heavier oils and waxes in it are far more likely the cause.

Is Diethylhexyl Syringylidenemalonate a UV filter?

No. It is an antioxidant and filter stabilizer, not a UV filter, so it does not absorb or block UV light on its own. Its role is to keep the actual UV filters stable and protect the formula from oxidation, which helps the sunscreen hold up better. It is easy to confuse with a filter because it appears in the sun-protection part of a label.

Is Diethylhexyl Syringylidenemalonate natural?

No, it is a synthetic ingredient made in a lab, commonly known by the trade name Oxynex ST. Synthetic here simply means it was engineered to be a stable, oil-soluble antioxidant, not that it is unsafe.

Sunscreens with Diethylhexyl Syringylidenemalonate

We rate 178 sunscreens that contain it, showing the top 10 by overall score:

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