In short
Citral is a mixture of the isomers geranial and neral and is the molecule behind the smell of lemon. It occurs abundantly in lemongrass and litsea cubeba oils and is also made synthetically.
What Citral smells like
Citral is the essence of lemon: intense, sharp and fresh, with a sweet, tangy green nuance. The Good Scents Company lists sharp, lemon, sweet, and fresh, juicy lemon peel with a sweet tangy green nuance. It is a mixture of two isomers — geranial gives the sharp, diffusive lemon blast, neral a softer, sweeter, slightly floral undertone. It is more concentrated and linear than a whole lemon oil, in which it is only a few per cent yet carries the lemon character. It is one of the 26 fragrance allergens individually named in EU cosmetics law.
- Leading note
- Sharp lemon
- Supporting facets
- Sweet, green
- Faint facets
- Slightly floral
- Character
- Sharp, intense, diffusive, linear
What makes Citral distinctive
It is lemon made literal and loud. Lemon oil is rounder and more complex; citral is the sharp lemon idea on its own — which is why it smells more like 'lemon' than the fruit does.
How Citral is used
Used for lemon notes in fragrance and flavour, in citrus reconstructions, and as a raw material for ionones. It is unstable in alkaline and oxidising products.
Typical role: modifier (used in small amounts to change the character of a blend); lift (adds diffusion and radiance, especially at the top).
How Citral differs from similar materials
- Lemon Oil (Cold-Pressed)
- Lemon oil is rounder and more complex, mostly limonene with citral a few per cent; citral is the concentrated, linear lemon.
- Citral Dimethyl Acetal
- Suppliers describe the acetal as milder and more natural lemon than citral, and more stable; citral is sharper and more intense. (compared directly by a cited source)
- Litsea Cubeba Oil
- Litsea cubeba oil is mostly citral, softened by sweet-green and woody-floral nuances; citral itself is the sharp lemon core.
- Lemongrass Oil
- Lemongrass oil is citral-rich but grassy, herbaceous and tea-like; citral is purer, sharper lemon.
- Citronellal
- One glossary describes citronellal as less piercing than citral, and rosier and greener; citral is the sharper, purer lemon. (compared directly by a cited source)
An asterisk marks a difference that a cited source states directly. The others compare the published descriptions of each material. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.
Formulation considerations
Unstable in alkaline media such as soap and can degrade in alcohol over time. It is a restricted and declarable allergenic material, so its total from all sources — including lemongrass and litsea — must be tracked.
Identity and classification
- Type
- Aroma chemical
- Origin
- Occurs in nature
- Odour family
- Citrus / Green
- Note position
- Top note
- Physical form at room temperature
- Liquid
- Also known as
- Geranial and neral
- CAS number
- 5392-40-5
- Molecular formula
- C10H16O
- Molecular weight
- 152.23 g/mol
- IUPAC name
- (2E)-3,7-dimethylocta-2,6-dienal
The CAS number, formula and molecular weight are taken from PubChem compound 638011, whose own record lists this CAS number; checked 19 October 2026.
Safety and compliance
The IFRA Standards Library lists a Standard covering Citral:
- "Citral" — Restriction, 49th Amendment, published 2020-01
Limits differ by product category and are set out in the Standard itself; this page does not reproduce them. The list above reflects the library as read on 19 October 2026.
Citral is one of the 26 fragrance allergens listed individually in Annex III of the EU Cosmetics Regulation (label name: Citral), which must be named on cosmetic labels above 0.001% in leave-on and 0.01% in rinse-off products. Regulation (EU) 2023/1545 extended the list; see the fragrance allergens list.
Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. It has a harmonised EU classification (Regulation (EC) No 1272/2008, Annex VI): H315 causes skin irritation; H317 may cause an allergic skin reaction. Companies notifying the ECHA C&L Inventory classify it (3,008 reports): H319 causes serious eye irritation (17.4% of reports). 1 of the reports find it does not meet the hazard criteria. A skin sensitiser classification concerns handling the neat material and the dose in a finished product; the IFRA Standards, where they apply, set the limits. Unless it is harmonised, this is the notifiers' own classification, not a binding one.
This page is general information, not a safety assessment or a specification. Confirm identity, composition, IFRA status and allergen content from your supplier's documents for the lot you hold.
Materials it works with
-
Lemon Oil (Cold-Pressed)
Essential oil · Citrus / Aldehydic — citrus, sharp, zesty, juicy
-
Litsea Cubeba Oil
Essential oil · Citrus / Fruity — lemon, sweet, fruity, fresh
-
Ginger Oil
Essential oil · Spicy / Citrus — spicy, warm, lemony, woody
-
d-Limonene
Aroma chemical · Citrus / Fruity — citrus, orange, fresh, light
-
Citral Dimethyl Acetal
Aroma chemical · Citrus / Green — lemon, fresh, green, soft
Citral is also suggested as a partner on the pages for Lemon Verbena Oil, Lemongrass Oil, Lime Oil (Expressed), Melissa Oil and Methyl Heptenone.
Used in formulas and accords
Used in 11 published formulas
Citral is an ingredient in 10 accords and 1 base in the Formula & Accord Library.
Further reading
Questions about Citral
Is Citral natural or synthetic?
The molecule occurs in nature. Commercial Citral may be made by synthesis or obtained from natural sources, so check the supplier's specification if the distinction matters to you.
What is the CAS number of Citral?
5392-40-5. It was checked against PubChem on 19 October 2026.
Which published formulas use Citral?
Citral is used in 11 published formulas in the RUŌOD Lab Formula & Accord Library, including Aperol Spritz Accord, Champagne Accord and Coquito Accord. Each is listed with a link under "Used in formulas and accords" on this page.
Is Citral covered by an IFRA Standard?
Yes. The IFRA Standards Library lists a Standard covering it: "Citral" — Restriction, 49th Amendment. The limits depend on the product category; read the Standard itself before formulating.
Sources
- PubChem — compound 638011, checked 19 October 2026.
- PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
- IFRA — Standards Library, read 19 October 2026.
- EUR-Lex — Regulation (EC) No 1223/2009, Annex III.
- The Good Scents Company — citral — odour database.
- Premiere Peau — Citral — published perfumery reference.
- ChemicalBook — citral — odour database.
- Olfactory profile: the RUŌOD Lab team's synthesis of the published descriptions above, reviewed 20 October 2026. Evidence: several independent published descriptions, which agree. Classification and the short description: revision 1. Descriptions of odour are judgement, not measurement.