thymol

Thymol is a natural monoterpene phenol with the chemical formula C10H14O and the IUPAC name 5-methyl-2-isopropylphenol. It is one of the major constituents of thyme essential oil, derived from Thymus vulgaris, and occurs in smaller amounts in other members of the Lamiaceae such as oregano. Thymol contributes to the characteristic aroma of thyme and has long been used for its antiseptic properties.

In essential oils, thymol typically appears alongside other terpenoids such as p-cymene and carvacrol. It is a white to off-white crystalline solid with a phenolic odor. It is sparingly soluble in water and more soluble in organic solvents. The compound is a weak acid due to its phenolic hydroxyl group and can form phenoxide salts under basic conditions.

Thymol has a range of uses in food, medicine, and consumer products. It is employed as a flavoring and fragrance agent and is approved as a food additive in some regulatory systems. It is also valued for antimicrobial and antifungal properties and is used in mouthwashes, toothpaste, surface disinfectants, and certain topical antiseptics. In combination with other essential oil components, thymol can act synergistically to inhibit microbial growth.

Safety and regulation vary by jurisdiction. Thymol can be irritating at high concentrations and should be used in appropriate dilutions. It is typically sourced from natural thyme oil but can also be produced synthetically for industrial applications.