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Citral

Worth knowingFragrancefragrancemaskingEU-declared fragrance allergen

EU-restricted, a common contact allergen, or subject to live debate.

Also written as: Geranial · Neral · 3,7-Dimethyl-2,6-octadienal · Lemonal

What it is

Citral is a mixture of two closely related aldehydes, geranial and neral, that together produce a sharp lemon smell. It is the dominant component of lemongrass, litsea cubeba and lemon-scented tea tree oils, and is present in smaller amounts in lemon and orange peel oils. Formulators use it for bright citrus top notes, and it also turns up in products simply because a citrus or lemongrass extract is present.

What it does well

  • Gives a strong lemon note at low concentrations

    Citral is highly odour-active, so very little is needed. As with other aroma chemicals this is a formulation benefit rather than a benefit to the skin.

    Strong evidence

  • Shows antimicrobial activity in laboratory studies

    Citral inhibits several bacteria and fungi in vitro, which is often cited for lemongrass oil. The concentrations required are well above normal cosmetic fragrance levels, so it should not be relied on for acne or preservation.

    Limited evidence

Worth knowing

  • A recognised skin sensitiser and part of fragrance mix II

    Citral is one of the six components of the standard fragrance mix II screening panel, which around 4% of European dermatitis patients react to. Positive reactions to citral specifically are less common than to oxidised linalool or limonene but are well documented.

    Matters most toPeople with eczema or a known fragrance allergy.

  • Cross-reacts with geraniol

    Geraniol can be oxidised on the skin into geranial, one half of citral, which explains why people allergic to one often react to the other. Avoiding just one of the two may not be enough.

    Matters most toPeople with a confirmed geraniol or citral allergy.

  • Can be irritating in concentrated essential oils

    Citral-rich oils such as lemongrass and lemon-scented tea tree can sting or redden skin if used undiluted. In a finished face mask the level is normally a small fraction of a per cent.

    Matters most toPeople diluting essential oils at home or using very high essential-oil masks.

Where the EU stands

Concentration-restricted

One of the original 26 declared fragrance allergens, and now capped by concentration as well. The labelling threshold is unchanged: it must be named on the pack above 0.001% in leave-on products and 0.01% in rinse-off products. After the SCCS reassessed citral's sensitisation endpoint in 2024 (SCCS/1666/24), Regulation (EU) 2026/909, in force since 18 May 2026, replaced Annex III entry 70 with a table of maximum concentrations by product type. A leave-on mask falls under the leave-on skin row at 0.15%; a wash-off mask falls under the skin rinse-off row at 1.2%. Products that do not comply may not be placed on the EU market from 1 January 2027, nor made available from 1 July 2028, so masks on sale today are unaffected.

Regulation (EC) No 1223/2009, Annex III entry 70 (replaced by Regulation (EU) 2026/909) · source ↗

Sources (2)

Every link goes to the original: a journal, a PubMed record or an EU document.

  1. [1]
    Opinion on Citral (CAS No. 5392-40-5, EC No. 226-394-6) - sensitisation endpoint (SCCS/1666/24)

    SCCS - Scientific Committee on Consumer Safety, European Commission · 2024

    The SCCS concluded citral can be considered safe with respect to induction of sensitisation at the concentrations proposed for cosmetic use, while noting the underlying risk-assessment methodology needs further refinement.

  2. [2]
    Cross-reactivity between citral and geraniol - can it be attributed to oxidized geraniol?

    Contact Dermatitis · 2014 · doi:10.1111/cod.12293

    Reactions to citral and geraniol frequently occur together, most plausibly because geraniol is oxidised to geranial, meaning the two should be considered jointly when advising allergic patients.

Masks that contain Citral