Galaxolide

SyntheticPOPULAR & WEIRDmusky · clean · sweet

BasePyramid

3/5Strength

400hTenacity

3Origins

Specimen

N/A (synthetic molecule)

Definition

Transparent, slightly waxy sweetness pressed against clean cotton. Galaxolide is the invisible architecture of modern laundry — a polycyclic musk so ubiquitous it has been detected in the blood of over 90% of tested adults.

MUSKY SWEET CLEAN WOODY POWDERY METALLIC WARM

HHCB

Instruments

Pyramid

TTop

HHeart

BBase

3/5Strength

Medium

odour strength

Tenacity on blotter

400hours · 17 days

1 h6 h24 h3 d7 d400 h

at 100 %

Producing countries

China Germany Netherlands

Scent

Clean, sweet, musky — with a faint metallic edge that reads almost mineral on first contact. Drier and cooler than Habanolide's watery linen character; less creamy than Ethylene Brassylate; entirely without the animalic undertow of muscone. There is a soft woodiness beneath the sweetness, like cotton dried on a cedar shelf.

On skin, the metallic sharpness fades within minutes, leaving a quiet, near-subliminal warmth that sits close to the body. The molecule never projects forcefully — it radiates. In large doses, a soapy-powdery quality emerges; at trace levels, it functions as pure texture, adding density to a composition without announcing itself.

In PREMIEREPEAU

DISCOVERY SET7 × 2 ml →

The Full Story

Galaxolide (HHCB, CAS 1222-05-5) is a polycyclic iso-chroman musk, molecular formula C₁₈H₂₆O, molecular weight 258.4 g/mol. Its IUPAC name — 4,6,6,7,8,8-hexamethyl-1,3,4,6,7,8-hexahydrocyclopenta[g]isochromene — describes a rigid, compact ring system that locks in musk character while resisting metabolic degradation. Commercial product is a viscous liquid (mp −20 °C, bp ~326 °C at 760 mmHg), supplied either pure or as a 50% dilution in dipropylene glycol.

The molecule has two chiral centres (C-4 and C-7), yielding four stereoisomers. Only the (4S)-isomers carry significant musk odour: the (4S,7R) form shows an odour threshold below 1 ng/L in air — among the lowest of any synthetic musk. This enantioselectivity, demonstrated by Kraft and Fráter (Helvetica Chimica Acta, 1999; Chirality, 2001), is unusually pronounced and provides strong evidence for receptor-mediated olfaction. The commercial product is a racemic mixture of all four isomers, meaning roughly half the material is olfactively inert.

The scent is clean, sweet, faintly metallic, with a soft woody undertone — the olfactory definition of laundered fabric. It reads cooler and more transparent than macrocyclic musks (Habanolide, Exaltolide) and lacks the animalic warmth of muscone. Substantivity is extraordinary: approximately 400 hours at full concentration on blotter, which explains its dominance in functional perfumery — detergents, fabric softeners, soaps. By the late 1980s, annual production exceeded 6,000 tonnes, making it one of the highest-tonnage aroma chemicals ever produced.

Galaxolide is highly lipophilic (logP ~5.3) and resistant to wastewater treatment. It has been detected in freshwater fish, human breast milk (97% of samples in one US cohort), blood plasma (91% detection in Austrian young adults, Hutter et al.), and adipose tissue. In January 2025, France's ANSES proposed classifying Galaxolide as a Category 1B reproductive toxicant (H360Df) under the EU CLP Regulation, based on multigenerational rat studies showing effects on reproductive organs. European consumption has fallen approximately 35% between 2005 and 2023 as formulators shift toward macrocyclic alternatives with better biodegradability.

Related notes: Amber · Ambergris · Ambrette · Ambroxan · Cashmeran · Cashmere · Ethylene Brassylate · Iso E Super

Extraction & Chemistry

Extraction method

Purely synthetic — no natural source exists. Synthesised from petrochemical precursors via a multi-step pathway: 1,1,2,3,3-pentamethylindane (prepared by cycloaddition of tert-amylene to alpha-methylstyrene) is hydroxyalkylated with propylene oxide in a Friedel-Crafts reaction using aluminium chloride as catalyst. Ring closure to the iso-chroman structure is accomplished with paraformaldehyde. The commercial product is a viscous, colourless liquid — a racemic mixture of four stereoisomers. Available at >50% purity (solution) or >99% purity from speciality suppliers.

Formula: C18H26O
CAS: 1222-05-5
Botanical: N/A (synthetic molecule)
Appearance: colorless clear oily liquid
Odour strength: Medium
Lasting power: 400 hours at 100.00%
Synonyms: HHCB

IFRA status

Restricted

Permitted by IFRA (51st Amendment, 2024): max 1.5% in Category 4 leave-on products, higher limits for rinse-off. Classified EU CLP for acute and chronic aquatic toxicity (Category 1). In January 2025, ANSES (France) proposed harmonised classification as Repr. 1B (H360Df) — under ECHA public consultation as of early 2025.

Physical properties

Boiling point: 326.30 °C @ 760 mm Hg (est.)
Flash point: >212 °F TCC (>100 °C)
Specific gravity: 1.037 to 1.047 @ 25 °C
Refractive index: 1.516 to 1.526 @ 20 °C

In Perfumery

Galaxolide is a base-note fixative and volume builder — its role is structural, not decorative. At molecular weight 258.4 and logP 5.3, it sits firmly in the low-volatility, high-substantivity zone, anchoring compositions that would otherwise evaporate within hours. Its 400-hour blotter persistence is strong among polycyclic musks. In functional perfumery (detergents, softeners), Galaxolide is often the single largest component by weight, dosed at 5-10% of the fragrance oil. In fine fragrance, it is used more judiciously — typically 0.5-3% of the concentrate — as a transparent musk bed beneath floral, woody, or citrus constructions. It serves every major fragrance family: in fougères, it replaces the musk base once provided by nitro musks (now largely banned); in white florals, it adds radiance without animalic weight; in fresh colognes, it extends citrus top notes into the dry-down. Key blending partners include Iso E Super (CAS 54464-57-2) for transparent woody volume, Habanolide (CAS 111879-80-2) for watery-linen warmth, Ethylene Brassylate (CAS 105-95-3) for powdery softness, and hedione (CAS 24851-98-7) for radiant floral diffusion. Environmental pressure is driving reformulation toward macrocyclic musks — Exaltolide (CAS 106-02-5), Ambrettolide, Helvetolide — which biodegrade more readily.

Role in the formula

01fixative

02diffusion enhancer

03modifier

04signature note

05blender

06volume builder

Available as

synthetic

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