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BHT

What BHT is & what it does

Butylated hydroxytoluene, a synthetic antioxidant used at tiny levels to keep a formula's oils and fragrances from going rancid. It protects the product rather than the skin.

What is BHT and what does it do in sunscreen?

BHT (butylated hydroxytoluene) is a synthetic antioxidant used at very small levels. In a sunscreen its job is to protect the formula, not the skin: it slows the oxidation that would otherwise turn the oils and fragrance rancid. By keeping those components stable, it helps the product look, smell, and perform consistently over its shelf life.

Is BHT safe?

Yes, at the tiny amounts used in cosmetics. BHT is a long-used antioxidant that also appears as a food preservative under the E-number E321. It sits very low on the ingredient list because only a trace is needed to keep oils from going off, and at those levels it is well tolerated for most people.

Does BHT clog pores?

Generally no. BHT is not flagged as comedogenic and is present only in trace amounts as a formula stabilizer, not as an oil or wax. If you are breaking out, the richer emollients and filters elsewhere in a sunscreen are far more likely the cause.

Is BHT a preservative?

Not in the usual sense. BHT is an antioxidant: it stops the oils and fragrance from oxidizing and going rancid, but it does not kill or stop the microbes that a true preservative controls. The antimicrobial preserving in a sunscreen is handled by ingredients like phenoxyethanol or ethylhexylglycerin instead.

Is BHT natural or synthetic?

BHT is synthetic. It is made in a lab rather than extracted from a plant, which is what allows it to work reliably at the trace levels formulators need. The same compound is also used as an antioxidant in foods and packaging.

Sunscreens with BHT

We rate 1136 sunscreens that contain it, showing the top 10 by overall score:

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