Propylene Glycol

What Propylene Glycol smells like

Propylene glycol is a viscous, colourless liquid, nearly odourless but with a faintly sweet taste, in Wikipedia's description. It dissolves many resins, dyes and essential oils, is miscible with water and many solvents, and is used as a carrier for flavours in preference to ethanol because its low volatility gives a more uniform flavour.

Leading note

No single note leads in the published descriptions

Character

Neutral, low-volatility

• odourless

What makes Propylene Glycol distinctive

A nearly odourless, water-miscible carrier — common in flavours and functional products.

How Propylene Glycol is used

Used as a carrier and solvent in flavours, cosmetics and functional fragrance.

Typical role: solvent (dilutes or carries other materials).

How Propylene Glycol differs from similar materials

Dipropylene Glycol (DPG)

DPG is the usual low-odour perfumery diluent; propylene glycol is more common in flavours and water-based products.

Glycerol

Glycerol is thicker and dissolves far fewer perfume materials; it is used as a humectant rather than a diluent.

Each difference compares the published descriptions of the two materials. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.

Formulation considerations

It does not dissolve all fragrance materials well and is more hygroscopic than DPG; test solubility before replacing DPG with it.

Identity and classification

Type

Solvent or carrier

Origin

Synthetic

Odour family

No odour family

Note position

Base note

Physical form at room temperature

Liquid

Also known as

1,2-Propanediol, PG

CAS number

57-55-6

Molecular formula

C3H8O2

Molecular weight

76.09 g/mol

IUPAC name

propane-1,2-diol

The CAS number, formula and molecular weight are taken from PubChem compound 1030, whose own record lists this CAS number; checked 19 October 2026.

Safety and compliance

Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. Companies notifying the ECHA C&L Inventory report it as not meeting the GHS hazard criteria (6,762 of 6,899 reports). 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

• Dipropylene Glycol (DPG)

  Solvent or carrier · No odour family — odourless

• Ethanol (Perfumer's Alcohol)

  Solvent or carrier · No odour family — alcoholic, volatile

• Triethyl Citrate

  Solvent or carrier · No odour family — odourless

Propylene Glycol is also suggested as a partner on the pages for Glycerol.

Used in formulas and accords

Not currently used in any published formula.

The Formula & Accord Library lists Propylene Glycol here as soon as a published formula, accord or base uses it.

Further reading

• Is Your Fragrance Oil Already Diluted? Carrier Solvents Explained

  Many purchased fragrance oils are cut with DPG, IPM or benzyl benzoate. How to find out, what it does to your concentration, and how IFRA certificates treat it.

Questions about Propylene Glycol

Sources

• PubChem — compound 1030, checked 19 October 2026.
• PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
• Wikipedia — Propylene glycol — published perfumery reference.
• PCC Group — Propylene glycol — manufacturer's description.
• Olfactory profile: the RUŌOD Lab team's synthesis of the published descriptions above, reviewed 24 October 2026. Evidence: more than one published description. Classification and the short description: revision 1. Descriptions of odour are judgement, not measurement.