Azulene

AKA: 275-51-4, Cyclopentacycloheptene, Azunamic, Bicyclo[5.3.0]decapentaene, Bicyclo(5.3.0)decapentaene, Bicyclo(5.3.0)-1, 3, 5, 7, 9-decapentaene, Bicyclo(5.3.0)-deca-2, 4, 6, 8, 10-pentaene
Synthetic
Soothing
Skin Conditioner
Not Clean
Azulene is one of over 100 different polycyclic aromatic hydrocarbons (PAHs). PAHs are chemicals that are formed during the incomplete burning organic substances, such as fossil fuels. They are usually found as a mixture containing two or more of these compounds. (L10)
Formula
C10H8
Mol. Weight
128.17
CAS #
275-51-4
Form
Powder
Functions
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Soothing
Calms redness, irritation, and inflammation. Your skin's chill pill — great for sensitive, reactive, or post-procedure skin.
Soothes Skin
Traditional Use
Isolated from chamomile and wormwood essential oils in the early 20th century; historically used in traditional European herbalism for inflammation. Its blue color and soothing properties made it popular in cosmetics starting in the 1950s.
EWG
3
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
ewg-3
medical-approval
all-shades-safe
Regulatory Status
USApermitted
EUrestricted
JAPANrestricted
CANADArestricted
Skin Types
all-skin-types
Best For
Irritation
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewed1 paper
⚖️Regulatory1 listing
🛡️Safety-assessed2 reviews
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR