Short answer
A fragrance material can be identified by a common name, a trade name, an INCI name and a CAS number, and each identifies something different. A CAS number identifies a chemical substance and is the most reliable identifier for single aroma chemicals; trade names identify one manufacturer's product; INCI names are what appear on cosmetic labels; common names are convenient and ambiguous. Record the specific product you bought, plus every identifier that applies, so a formula still means the same thing years later.
The identifiers, and what each one pins down
| Identifier | Example | Identifies | Limitation |
|---|---|---|---|
| Common name | Linalool | A substance, informally | Several names for one substance; one name for several products |
| Chemical name | 3,7-dimethylocta-1,6-dien-3-ol | The molecule | Long; conventions vary |
| CAS number | 78-70-6 (linalool) | A registered chemical substance | Does not identify grade, purity, supplier or isomer mix in every case |
| Trade name | Hedione, Iso E Super | One manufacturer's product | Owned by that company; equivalents from others have other names |
| INCI name | Linalool; Citrus Aurantium Bergamia Peel Oil | The name used in cosmetic ingredient lists | Designed for labels, not for identifying a specific product |
| Supplier code | Your supplier's catalog number | The exact product you bought | Meaningful only with that supplier |
CAS numbers
CAS Registry Numbers are assigned by the Chemical Abstracts Service, a division of the American Chemical Society, to chemical substances. They are the closest thing to a universal identifier for a single aroma chemical, and suppliers, safety data sheets and regulatory lists all use them. A CAS number has a check digit, so a mistyped number can often be detected.
They have limits. Some substances have several CAS numbers (for different isomers, mixtures or historical registrations). Natural extracts may have a CAS number that describes a general category — "oil of a species" — not your specific oil, its origin or its process. And a CAS number says nothing about purity or grade. Record it, but alongside the product identity, not instead of it.
Trade names
Many important aroma chemicals are known by trade names that belong to the company that developed them — Hedione is a Firmenich (now dsm-firmenich) name for methyl dihydrojasmonate; Iso E Super is an IFF name. Other manufacturers sell chemically similar materials under their own names, and grades can differ in isomer composition and therefore in smell. If a formula says "Hedione", it should mean that product; if you substitute a generic methyl dihydrojasmonate, record it as a different material, because it may smell different.
INCI names and labels
INCI names are the standardized names used in cosmetic ingredient lists in many markets. In the EU, fragrance is declared as "parfum" and certain allergens by their listed names when above threshold — and the 2023 update changed some of those names and grouped some substances (geranial and neral are declared together as "Citral", for instance). If your records use the same names as the regulation, preparing a label is much less error-prone. See EU fragrance allergen labelling.
A naming convention that works
For each material record, we suggest:
- Display name: the specific product — "Bergamot oil FCF, Italy" rather than "Bergamot".
- Internal code: short and unique, never reused, e.g. "NAT-0142" or "AC-0031".
- CAS number for single chemicals; the supplier's stated CAS for naturals, noted as such.
- Botanical name and plant part for naturals.
- Supplier and supplier's product code.
- Synonyms you or others use, so searches find it.
Apply the convention to dilutions too: "Ambroxan 10% in DPG" names the parent, strength and solvent. And never rename a material in a way that changes what it refers to — if the product changes, make a new record. How this fits into the wider structure of a material library is covered in how to build a perfume ingredient database.
When names collide with supplier changes
A common trap: a material is reordered from a different supplier under the same common name and goes into the same record. The formula now refers to a different product without anyone deciding so. Treat a supplier change as a new material record, or at least a recorded change with re-evaluation — documenting raw material supplier changes covers the procedure.
The rest of what a material record should hold is in the raw material documentation guide.
Sources
Frequently asked questions
Where do I find a material's CAS number?
On the supplier's safety data sheet or specification, usually in the composition section. For single chemicals, it is also widely listed in reference sources.
Do essential oils have CAS numbers?
Many do, but the number describes a type of oil, not a specific product. Two lavender oils with the same CAS number can smell quite different.
Written and reviewed by the RUŌOD Lab team. This article is general education about perfume formulation and record-keeping; it is not legal, regulatory or safety advice, and the examples are illustrations, not validated commercial formulas. How we write and check these guides.