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O-Cymen-5-Ol

What O-Cymen-5-Ol is & what it does

A mild antimicrobial preservative (also called IPBC-free biosol) that protects against bacteria and fungi. It is effective at low levels and well tolerated.

What is O-Cymen-5-Ol and what does it do in sunscreen?

O-Cymen-5-Ol is a mild antimicrobial preservative, also known as biosol. In a sunscreen its job is to protect the formula from bacteria and fungi so the product stays safe and stable over its shelf life. It is effective at low levels and is generally well tolerated, which is why it appears in many face and body sunscreens.

Is O-Cymen-5-Ol safe?

Yes, at the low levels used in cosmetics. It is a long-established preservative used in small amounts to keep products microbe-free, and it is considered well tolerated by most skin. Without a preservative like it, a water-containing sunscreen would spoil and become unsafe to use.

Does O-Cymen-5-Ol clog pores?

No. It is a preservative used in very small amounts, not an oil or wax, so it is not a pore-clogging ingredient. If a sunscreen is breaking you out, the heavier emollients in the formula are far more likely responsible than the preservative.

Is O-Cymen-5-Ol a preservative?

Yes. O-Cymen-5-Ol is an antimicrobial preservative whose role is to stop bacteria and fungi growing in the product. It is sometimes confused with active or fragrance ingredients because of its chemical-sounding name, but its only job here is to keep the formula stable and safe over time. You will often see it near other preservatives on the ingredient list.

What else is O-Cymen-5-Ol called?

On the label it appears as its INCI name, O-Cymen-5-Ol. It is also known as biosol and, chemically, as 4-isopropyl-3-methylphenol, a thymol-related compound. These are different names for the same mild preservative.

Is O-Cymen-5-Ol natural?

It is synthetic. It is a lab-made phenol related to thymol, the aromatic compound found in thyme, but the cosmetic ingredient itself is manufactured for purity and consistency. Natural or not, its role is simply to keep the product free of microbes.

Sunscreens with O-Cymen-5-Ol

We rate 105 sunscreens that contain it, showing the top 10 by overall score:

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