Pentamethyl Octahydroindenodioxane

INCI: Pentamethyl Octahydroindenodioxane | Function: Fragrance | Type: Fragrance (Synthetic Musk)

What Is Pentamethyl Octahydroindenodioxane?

Pentamethyl Octahydroindenodioxane is a polycyclic synthetic musk compound structurally related to Galaxolide (HHCB). It functions as a fragrance ingredient providing clean, long-lasting musky notes to cosmetic and personal care products. Synthetic musks are valued for their substantivity — they bind to fabrics and skin, releasing fragrance over extended periods.

Key Skin Benefits

+ Long-lasting musk scent — persists for 12+ hours
+ Fragrance fixative — extends other notes' longevity
+ Clean laundry-like scent profile — popular in functional fragrances

Pros

+ Excellent substantivity on skin and fabrics
+ Cost-effective alternative to natural musk
+ Broad compatibility with fragrance compositions

Cons

− Polycyclic musk — environmental persistence concern
− Bioaccumulation potential in aquatic ecosystems
− Potential fragrance allergen — IFRA restricted
− Not biodegradable — accumulates in sediment and biota

Specifications

Property	Value
Usage Areas	Face, Body, Hair
Product Type	Leave-On, Rinse-Off
Source	Synthetic
Natural Level	Synthetic

Safety Ratings

Metric	Rating
Skin Sensitivity	2/5
Comedogenic Rating	0/5
EWG Score	5/10

Regional Regulatory Limits

Region	Leave-on %	Rinse-off %	Status
EU (CosIng)	IFRA limit	IFRA limit	Allowed — IFRA restricted
US (CIR/FDA)	No limit	No limit	Allowed
Japan (MHLW)	No limit	No limit	Allowed
ASEAN	IFRA limit	IFRA limit	Allowed
China (NMPA)	No limit	No limit	Allowed

Typical Usage % by Product Type

Product Type	Typical %
Fragrance Compositions	0.5–10%
Fabric Conditioners	0.1–2%
Perfumes	1–5%

References

CosIng Database — Pentamethyl Octahydroindenodioxane. https://ec.europa.eu/growth/tools-databases/cosing/
IFRA Standards — Polycyclic Musks Safety Assessment.
EWG Skin Deep — Pentamethyl Octahydroindenodioxane. https://www.ewg.org/skindeep/

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