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.
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.
Evolution over time
Immediately
Immediately
Clean, sweet, faintly metallic — a transparent musk with soapy brightness and a cool, almost mineral edge
After a few hours
After a few hours
Metallic sharpness dissolves; soft, warm, powdery musk sits close to skin. Cedar-shelf woodiness emerges beneath the sweetness
After a few days
After a few days
Near-subliminal clean radiance on fabric. Detectable on cotton for several days — quiet, sweet, intimate
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. The dossier is now under public consultation at ECHA. European consumption has fallen approximately 35% between 2005 and 2023 as formulators shift toward macrocyclic alternatives with better biodegradability.
This note in Première Peau. Albâtre Sépia · Doppel Dänçers · Gravitas Capitale · Rose Monotone. Sample all seven extraits in the Discovery Set.
Only half of commercial Galaxolide actually smells like musk. The molecule has two chiral centres, producing four stereoisomers, but the musk odour resides almost entirely in the (4S)-configured pair — the (4R)-isomers are near-odourless. Kraft and Fráter demonstrated this in 1999 by resolving all four isomers and testing them individually. An enantiopure (4S,7R)-Galaxolide would be roughly twice as potent per gram as the commercial racemate.
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.
Molecular Formula
C18H26O
CAS Number
1222-05-5
Botanical Name
N/A (synthetic molecule)
IFRA Status
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.
Synonyms
HHCB
Physical Properties
Odor Strength
Medium
Lasting Power
400 hours at 100.00%
Appearance
colorless clear oily liquid
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.
