Like many other plants, cannabis contains terpenes and flavonoids. Terpenes impart the strong odors characteristic of good weed and have therapeutic properties of their own. Terpenes also interact with cannabinoids in ways that affect how the body absorbs and utilizes them.
Terpenes are used in aromatherapy to alter mood, attitude and outlook, as well as for physical effects. When used in conjunction with cannabis they influence the high. Most experienced marijuana consumers understand this informally. If you were to be handed a bud, your first action would be probably be to look at it. The second thing you would do is smell it. THC, CBD and the other cannabinoids have no odor. What you would be smelling are the terpenes. You know from experience that the odor of the bud is an indication of the kind of high it produces. That's why two different varieties that have the some THC content can have different effects -- its the terpenes.
You could say THC is the engine that drives the high and the terpenes are the steering wheel. Is it taking you up? Is it focusing, relaxing, or making you tired or energetic? It's the terpenes.
Some terpenes, such as myrcene, have an effect once they enter the bloodstream. Myrcene passes through the blood-brain barrier and increases its porosity to so that more THC enters faster, causing a quick-onset high. B-caryophyllene is associated with a relaxed feeling and sociability. Other terpenes have other special effects. Terpenes may have more effect on the high and some medical condition than CBD or cannabinoids other than THC.
Two of the most important terpenes in terms of their effects are myrcene and linalool.
Myrcene is the most abundant terpene in most varieties. It has anti-inflammatory, analgesic, antibiotic and antimutagenic properties. It is found in cavicol and other varieties of mangoes.
Beta caryophyllene lightens people's moods and helps them socialize. It has anti-inflammatory, antimalarial and cytoprotective properties.
Linalool is also found in lavender, roses and some citrus. It is typically only about 5% of the essential oils in marijuana, but it has important biological effects. Linalool is the most powerful sedative of all the terpenes. It is antidepressant and helps reduce anxiety.
Alpha pinene has a pine-like odor and has anti-inflammatory, antibiotic, stiumlant and other properties.
Limonene is found in abundance in citrus. It is focusing, stimulating, antidepressant and helps reduce anxiety.
Terpineol has antibiotic, antioxidant and anti malarial properties. It has a vaporizing temperature of more than 426F, notably higher than some cannabinoids and other terpenes.
Excerpted from Beyond Buds: Marijuana Extracts by Ed Rosenthal, copyright 2014.