Polypentene
AKA “PENTANE, n-Pentane, Pentan, Skellysolve A, Pentanen, Pentani, Amyl hydride, Tetrafume”
Synthetic
Ingredient Facts
Polypentene
AKA: PENTANE, N-Pentane, Pentan, Skellysolve A, Pentanen, Pentani, Amyl hydride, Tetrafume
Synthetic · Emollient · EWG: 4
Synthetic
Emollient
Occlusive
Skin Conditioner
Synthetic
Clean
Creates a protective layer on skin and hair to lock in moisture and smooth the surface for a polished finish.
Solubility less than 1 mg/mL at 70 °F (NTP, 1992)
Formula
C5H12
Mol. Weight
72.15
CAS #
9078-70-0
Form
Powder
State
N-pentane appears as a clear colorless liquid with a petroleum-like odor. Flash point 57 °F. Boiling point 97 °F. Less dense than water and insoluble in water. Hence floats on water. Vapors are heavie
See origin →
Functions
Film Forming
Creates a physical seal on skin to lock moisture in and keep irritants out. The "slugging" ingredient — barrier protection.
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Emollient
Fills in the tiny cracks between skin cells to make everything feel smooth and soft. The "silky finish" ingredient.
Creates Protective Barrier
Traditional Use
A synthetic polymer derived from petroleum olefins, developed in the mid-20th century. Used in cosmetics as an emollient and texture enhancer, replacing some functions of traditional mineral oils.
Skin Types
●all-skin-types
Best For
General
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Yes
RIFM fragrance ingredient safety assessment, pentanedioic acid, 1,5-dimethyl ester, CAS Registry Number 1119-40-0.
Api AM, Belsito D, Botelho D, Browne D, Bruze M et al.
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 2018
Final Report of the Safety Assessment of Isobutane, Isopentane, n-Butane, and Propane
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Final Report on the Safety Assessment of Isostearyl Neopentanoate
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Isobutane, Butane, Isopentane and Propane
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Diethylpentanediol Dineopentanoate
European Commission
EU Cosmetic Ingredient Database (CosIng)
Ethylhexyl Neopentanoate
European Commission
EU Cosmetic Ingredient Database (CosIng)
Isodecyl Neopentanoate
European Commission
EU Cosmetic Ingredient Database (CosIng)
Isohexyl Neopentanoate
European Commission
EU Cosmetic Ingredient Database (CosIng)
Isopentane
European Commission
EU Cosmetic Ingredient Database (CosIng)
Isostearyl Neopentanoate
European Commission
EU Cosmetic Ingredient Database (CosIng)
Myristyl Neopentanoate
European Commission
EU Cosmetic Ingredient Database (CosIng)
Octyldodecyl Neopentanoate
European Commission
EU Cosmetic Ingredient Database (CosIng)
Polypentene
European Commission
EU Cosmetic Ingredient Database (CosIng)
Tridecyl Neopentanoate
European Commission
EU Cosmetic Ingredient Database (CosIng)
Trimethyl Pentanyl Diisobutyrate
European Commission
EU Cosmetic Ingredient Database (CosIng)
Trimethylpentanediol/Adipic Acid/Glycerin Crosspolymer
European Commission
EU Cosmetic Ingredient Database (CosIng)
Trimethylpentanediol/Isophthalic Acid/Trimellitic Anhydride Copolymer
European Commission
EU Cosmetic Ingredient Database (CosIng)
1,5-Pentanediol
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
2,2,4-Trimethyl-1,3-Pentanediol Monoisobutyrate
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Ethylhexyl Neopentanoate
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Isodecyl Neopentanoate
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Isopentane
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Isostearyl Neopentanoate
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Octyldodecyl Neopentanoate
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Tridecyl Neopentanoate
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Trimethyl Pentanyl Diisobutyrate
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Trimethylpentanediol/Adipic Acid/Glycerin Crosspolymer
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Allergic Contact Dermatitis to Trimethylpentanediol/Adipic Acid/Glycerin Crosspolymer in a Lip Balm.
Lockmann A, Schill T, Schubert S, Buhl T
Contact dermatitis, 2026
A comparison of pentane-1,5-diol to other diols for use in dermatology.
Sundberg JJ, Faergemann J
Expert opinion on investigational drugs, 2008
Isobutane, Isopentane, Butane, and Propane.
Tucker R, Bergfeld WF, Belsito DV, Cohen DE, Klaassen CD et al.
International journal of toxicology, 2025
Isobutane, Isopentane, Butane, and Propane.
Tucker R, Bergfeld WF, Belsito DV, Cohen DE, Klaassen CD et al.
International journal of toxicology, 2025
Isobutane, Isopentane, Butane, and Propane.
Tucker R, Bergfeld WF, Belsito DV, Cohen DE, Klaassen CD et al.
International journal of toxicology, 2025
Verified Feb 2026
Data: PubChem · CosIng · EWG · CIR