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Tetramethyl Acetyloctahydronaphthalenes

OTNE

Depends on youFragrancefragrancemaskingEU-declared fragrance allergen

Genuinely relevant for some people, or depends on dose and pH.

Also written as: OTNE · Iso E Super · Acetyl Cedrene analogue · ISO E Super

What it is

OTNE is a mixture of closely related synthetic woody-amber molecules, sold commercially under names such as Iso E Super. It has a soft, velvety cedar-and-amber character and unusually good staying power, so it is used in a very large share of modern fragrances and scented cosmetics. It was among the substances the SCCS identified as an established contact allergen without individual labelling, and Regulation (EU) 2023/1545 corrected that.

What it does well

  • Adds volume and longevity to a fragrance at low cost

    It is one of the most-used fragrance ingredients in the world precisely because it is stable, cheap and blends with almost anything. This is a formulation benefit only.

    Strong evidence

Worth knowing

  • An established contact allergen that was previously invisible on labels

    Cases of allergic contact dermatitis to OTNE have been reported and it was one of the additional allergens the SCCS flagged for individual labelling. Because it was hidden inside Parfum until now, sensitised people had no way to avoid it.

    Matters most toPeople with unexplained fragrance-related dermatitis.

Where the EU stands

Labelling required

Added to the declared fragrance-allergen list by Regulation (EU) 2023/1545 as Annex III entry 344. Must be named on the pack above 0.001% in leave-on products and 0.01% in rinse-off products. Non-compliant products could be placed on the EU market until 31 July 2026 and sold from existing stock until 31 July 2028.

Regulation (EC) No 1223/2009, Annex III entry 344, as inserted by Regulation (EU) 2023/1545 · source ↗

Masks that contain Tetramethyl Acetyloctahydronaphthalenes