Alpha terpinene (α-terpinene) is one of three monoterpenes known as terpinene, along with beta-terpinene and gamma-terpinene. α-terpinene occurs naturally in many varieties of plants, including allspice, eucalyptus, citrus, juniper, cardamom,  marjoram, and cannabis. 

Known for its smoky, woody scent, α-terpinene is a colorless liquid that is most commonly utilized by adding more pleasant scents into industrial fluids. It is also used in the beauty and pharmaceutical industries as a flavor and aroma additive. In biology, it is known as both a component of volatile oil and as a plant metabolite.

As a constituent of tea tree oil, α-terpinene possesses strong antioxidant properties.¹ α-terpinene has also been researched as a potential cancer treatment. A study conducted by the Tropical Journal of Pharmaceutical Research found α-terpinene contributed to the inhibition of breast cancer cell growth.²

Like many terpenes, α-terpinene is referenced by a number of (potentially confusing) different names and synonyms. LabEffects’ list of known synonyms is as follows:

α-Terpinene synonyms and other names:

• Terpinene
• p-Mentha-1,3-diene
• Alpha Terpinene
• 1-Methyl-4-(1-methylethyl)-1,3-cyclohexadiene
• 1-isopropyl-4-methyl-1,3-cyclohexadiene

Cannabis strains with high concentrations of α-terpinene include Sentinel and Warwick #1.