Myrcene (beta-myrcene)

Structure and physical constants

Myrcene is the simplest of the common cannabis terpenes: an acyclic monoterpene, C10H16, molar mass about 136.24 g/mol, with two isolated double bonds and one conjugated diene. Beta-myrcene is the isomer of commercial and biological interest; alpha-myrcene is a rearranged isomer that is not a meaningful natural constituent. Its atmospheric boiling point is reported at about 166 to 168 degrees Celsius (331 to 334 degrees Fahrenheit). That figure is at one atmosphere and for the neat compound, and it is not a vaporizer set-point: in a dry-herb device myrcene is observed coming off plant material from roughly 155 degrees Celsius upward, well before its neat boiling point, because it is a dilute component evaporating from a matrix. The diene makes myrcene readily oxidised and readily polymerised, which is why aged or heat-abused material loses myrcene first and why a myrcene figure on an old certificate of analysis is the least durable number on the page.

Sources: Compiled from public compound databases (PubChem 2026* · Lanz C 2016

Sedative and analgesic pharmacology contested animal

The rodent data on myrcene are among the better-characterised of any cannabis terpene. Rao, Menezes and Viana reported that myrcene produced antinociception in mice and that the effect was reversed by naloxone, which points to opioid-system involvement rather than a direct cannabinoid mechanism. Lorenzetti and colleagues had already reported that myrcene reproduced the peripheral analgesic activity of lemongrass tea. do Vale and colleagues reported sedative and motor-relaxant central effects for myrcene among the Lippia alba chemotype constituents. Taken together this is a coherent animal picture of a sedating, peripherally analgesic monoterpene. What it is not is a demonstration of the same effects at the doses a human gets from inhaling flower or drinking a beer; the rodent doses were administered systemically and are substantially higher on a body-weight basis than realistic human exposure. The operator archive describes myrcene as having opioid analgesic effects. That claim is better supported than most terpene folklore and is retained here, with the naloxone-reversibility detail restored and the species qualifier attached.

Contested — caveat. Animal-only, systemic dosing, doses above realistic human dietary or inhaled exposure. Naloxone reversibility implicates the opioid system but the molecular target has not been identified.

Sources: Rao VSN 1990 · Lorenzetti BB 1991 · do Vale TG 2002 · marsresident / Van Kush Family (operator) 2016*

The blood-brain-barrier claim, and the mango contested anecdotal

The claim that myrcene increases blood-brain-barrier permeability, and therefore that myrcene-rich material or eating a mango beforehand potentiates THC, is the single most repeated statement in the popular cannabis literature. The primary-source support for it in humans is weak to absent. Tracing the citation chain leads to review articles that assert the permeability effect without a human study behind it, and to older secondary sources; the specific experiment — myrcene administered to humans, barrier permeability measured, cannabinoid brain penetration shown to increase — does not appear to exist. The mango practice compounds the problem with a dose question: mango flesh carries myrcene at a low fraction of a percent of a low essential-oil content, so the amount ingested from one fruit is small, and no pharmacokinetic study has shown it changes THC exposure. The mechanism is plausible on its face — small lipophilic monoterpenes do interact with membranes, and other terpenes are used as transdermal penetration enhancers — and it may yet turn out to be real. As of now it is a plausible mechanism with essentially no human evidence, and this shelf will not repeat it as fact. The honest formulation is: unproven, frequently asserted, worth testing.

Contested — caveat. CONTESTED. No human study demonstrates that myrcene increases blood-brain-barrier permeability or increases cannabinoid brain penetration. The claim propagates through review and popular literature by citation of secondary sources. The mango folk practice has a plausible mechanism and essentially no human evidence, and the ingested myrcene dose from one fruit is small.

Sources: Russo EB 2011 · Booth JK 2019 · Van Kush Family Research Institute (operator) 2026* · marsresident / Van Kush Family (operator) 2016*

Where myrcene actually is, and at what percent contested

Myrcene is typically the dominant terpene of both hop oil and most cannabis chemovars, which is why the two smell related. In hop oil it commonly runs from about 30 to well over 50 percent of the volatile fraction depending on variety and age, and because hop oil is a large share of what gives beer its aroma, beer is a much larger dietary myrcene exposure for most people than cannabis is. In cannabis the terpene fraction itself is roughly 1 to 4 percent of dry flower weight, and myrcene commonly occupies a large share of that fraction in indica-typed chemovars — but chemovar variation is wide and myrcene-poor cannabis is common. Note the two different denominators in the table below and read the source column.

Contested — caveat. Percent-of-oil and percent-of-product figures appear in the same table with different denominators, as marked in the Basis column. Hop and cannabis myrcene shares vary severalfold by variety, harvest and storage.

Sources: Russo EB 2011 · Booth JK 2019 · Lorenzetti BB 1991 · marsresident / Van Kush Family (operator) 2016* · Van Kush Family Research Institute (operator) 2026*

Industry notes contested

For a formulator, myrcene is the terpene most likely to be missing from a finished product relative to its label: it is volatile, it oxidises, and it is lost preferentially during drying, curing, distillation under heat, and open-vessel handling. For a lab tech, myrcene is also the analyte most sensitive to sample handling between receipt and injection — headspace losses during grinding and weighing are real and systematic. For a buyer, a high myrcene figure on a certificate of analysis for old stock should be treated with suspicion and cross-checked against the test date. Regulatory note: beta-myrcene has been listed as a substance of concern in some jurisdictional carcinogen listings on the basis of high-dose rodent bioassay data, which is a labelling and occupational-exposure matter for concentrate handlers rather than a statement about dietary exposure from hops or fruit.

Contested — caveat. The carcinogen-listing point is a regulatory-classification fact about high-dose rodent bioassays, not a risk statement about ordinary dietary or inhaled exposure. Check the specific jurisdiction and the specific listing before relying on it.

Sources: Compiled from public compound databases (PubChem 2026* · Sun J 2007*