Cedrol (Cedar Sesquiterpene Alcohol · Sedative · GABA-A Modulator · Insect Repellent)

Compound	Cedrol (α-Cedrol; 8,11,11-Trimethylbicyclo[5.4.0]undec-7-en-2-ol)
Chemical class	Terpenoid — Sesquiterpene Alcohol (Cedrane-type sesquiterpene; cedar aroma compound)
CAS	77-53-2
Primary source	Cedrus atlantica (Atlas cedar, wood essential oil), Juniperus virginiana (Eastern red cedar), Cupressus spp.
Key applications	Sedative/anxiolytic (aromatherapy; GABA potentiation); insect repellent; antifungal; anti-inflammatory
Claim strength	Moderate
Typical form	Cedarwood essential oil (cedrol 15–30% of oil); juniper berry oil; cedrol isolate
Buy from Herbuno	Juniper Berry Oil Soluble Extract - Juniperus communis Linn →

Name origin: From Cedrus (cedar genus; from Greek kedros = cedar). Cedrol is the primary sesquiterpene alcohol of cedarwood essential oils — responsible for cedar wood’s characteristic warm, woody, balsamic aroma. It is a bicyclic sesquiterpene of the cedrane skeleton (5,7-fused bicyclic ring system) with a tertiary hydroxyl group that gives it its alcoholic character and relatively high boiling point among sesquiterpenes. Traditional use: Cedar has been used since antiquity — Phoenician and Roman shipbuilding (rot resistance of cedar wood, partly attributed to cedrol’s antimicrobial and antifungal properties), Egyptian embalming (cedar oil as a preservative), and across multiple cultures for its aromatic properties in religious and medicinal contexts. Cedar chest and closet use for insect repellence (protecting clothing from moths) reflects cedrol’s documented insect-repellent activity. Research trajectory: Cedrol has attracted pharmacological research primarily for its CNS sedative/anxiolytic effects via inhalation — cedrol inhalation in human studies reduces heart rate, blood pressure, and subjective stress, effects linked to GABA potentiation and autonomic nervous system modulation. This represents one of the better-characterised aromatherapy pharmacological mechanisms. Commercial source: Juniper Berry Oil Soluble Extract from Herbuno delivers cedrol as part of the juniper sesquiterpene profile.

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Evidence for Cedrol Applications

Sedative/anxiolytic via inhalation (Moderate): Inhalation of cedrol in human volunteers produces significant reductions in heart rate and mean arterial blood pressure (Dayawansa et al., 2003, Auton Neurosci), consistent with parasympathetic activation. In animal models, inhaled cedrol reduces locomotor activity and potentiates barbiturate sleeping time (consistent with GABA-A enhancement). The pharmacological mechanism involves direct GABA-A receptor potentiation by cedrol absorbed through the olfactory pathway. Claim strength: Moderate (human physiological studies; animal mechanism).

Insect repellent: Cedrol is the primary active in cedar wood’s moth repellence — documented in laboratory bioassays against Tineola bisselliella (common clothes moth) and several mosquito species. The repellent potency is lower than DEET but significant among natural compounds. Claim strength: Moderate (bioassay; not human field trial).

Antifungal and antimicrobial: Cedrol demonstrates antifungal activity against Candida and dermatophyte species — contributing to cedarwood’s historical anti-rot properties in timber. MIC values are in the moderate range (higher than terpinen-4-ol). Claim strength: Moderate (in vitro).

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Frequently Asked Questions — Cedrol

Is cedarwood oil the same as cedar essential oil?
“Cedarwood oil” is a commercial term covering oils from multiple botanical sources: Atlas cedarwood (Cedrus atlantica — high cedrol, 15–30%); Virginia cedarwood (Juniperus virginiana — high thujopsene and cedrol); Texas cedarwood (Juniperus mexicana); Himalayan cedarwood (Cedrus deodara). The cedrol content varies significantly between sources — Atlas cedarwood typically has highest cedrol content. True cedar (Cedrus) is a conifer; Juniperus (juniper, used as cedarwood source) is a separate genus. This botanical diversity means “cedarwood oil” requires specific botanical sourcing disclosure in quality specifications.

How does cedrol’s aromatherapy mechanism work pharmacologically?
Inhaled cedrol molecules are absorbed directly through the olfactory epithelium and respiratory mucosa, entering the bloodstream without liver first-pass metabolism. From the bloodstream, cedrol can cross the blood-brain barrier (it is sufficiently lipophilic, logP ~4.5). In the brain, cedrol positively modulates GABA-A receptors, enhancing inhibitory tone and reducing sympathetic activation. The olfactory pathway also directly connects to the limbic system (amygdala, hippocampus) via the olfactory bulb — providing an additional indirect anxiolytic route that is unique to inhaled compounds. This dual mechanism (systemic GABA modulation + direct limbic olfactory signalling) explains why inhaled aromatherapy compounds like cedrol can produce real physiological effects beyond simple “pleasant scent.”

Does cedrol repel mosquitoes?
Cedrol has documented mosquito repellent activity in laboratory bioassays — it repels Aedes aegypti (dengue/Zika mosquito) and Anopheles (malaria mosquito) at relevant concentrations. The repellent efficacy is lower than DEET but higher than many other natural terpenes. Commercial cedar-based mosquito repellents are available, though typically as cedar oil blends rather than isolated cedrol. The repellent mechanism involves blocking mosquito olfactory receptors that detect host odour cues.

Is cedrol safe for use around pets?
Cedrol and cedarwood essential oils are generally considered less toxic to mammals than many other essential oils at equivalent exposures. However, cats lack sufficient glucuronidation capacity to metabolise many terpenes — making cats more susceptible to terpene toxicity than dogs or humans. Concentrated cedrol or cedarwood oil should not be applied directly to cats or used in confined spaces where cats are present. Dogs appear more tolerant but can also experience adverse effects from concentrated essential oil exposure. Diffuser use at low concentrations in ventilated spaces is generally considered acceptable for pet owners.

Related compounds: Terpinen-4-ol, Linalool, Beta-Caryophyllene, Alpha-Humulene

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Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.

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