Terpene Series: Myrcene

What are Terpenes?

Terpenes are a diverse class of organic hydrocarbon compounds that are often used as a means of defence by plants and insects that produce them due to their strong aroma and anti-bacterial effect. They are a major component of “essential oils”. Although sometimes used interchangeably with the word “terpenes”, terpenoids (or isoprenoids) are modified terpenes as they contain additional functional groups, usually oxygen-containing. For an overview of terpenes, go here. For a closer look at another common terpene, limonene, click here.

Terpenes are made up of linked, repeating isoprene molecules, making them quite volatile compounds and easily combustible. They have a range of attractive tastes and smells including that of fresh berries, citrus, mint and pine to name just a few.

Terpenes were adapted by the cannabis plant, as with other plants that produce them, as both a deterrent to predators and as an attractor to pollinators. Terpene production can be influenced by not only the strain of hemp, but the climate, weather, age, maturation, soil type and fertilisers that the plant is exposed to during its growth.

In the context of cannabis, terpenes are molecules secreted alongside cannabinoids like THC and CBD – they are not only aromatic but may also alter or enhance the function of other cannabinoids as well as providing physiological effects of their own when ingested. Unlike CBD and THC which are abundant, terpenes like myrcene are secreted in much smaller quantity. This is one of the reasons we isolate terpenes from multiple species of plants and add increased quantities to our broad-spectrum CBD oils.

What is Myrcene?

Myrcene is a colourless hydrocarbon classified as a monoterpene (a terpene consisting of two isoprene units); it is a terpene with a basic and simple structure as picture below:

Like many terpenes, myrcene can, in theory, be extracted from a number of plants including wild thyme (which has particularly high levels of myrcene) as well as cannabis, hops and cardamom.

Hops (Humulus lupulus), used for thousands of years in beer brewing and the evolutionary cousin of cannabis, is one of the richest sources of β-myrcene based on chemical composition data. Cannabis too is a rich source of myrcene and some strain-specific data shows that up to 65% of the steam-distilled essential oil from cannabis (Cannabis sativa L) is myrcene.

Industries, which make use of myrcene, including ours, source the terpene from multiple sources with the plant myrcia being the most popular – the namesake of the terpene.

The Science

Research into myrcene and terpenes, in general, is not as prevalent as cannabinoids such as THC and CBD although greater research effort is now being spent on investigating certain terpenes including myrcene because it is a particularly abundant compound in cannabis.

Rodent studies looking at the effects of terpenes have been conducted sporadically since the 1990’s and some preliminary yet interesting results have been recorded. For example, myrcene was shown to reduce pain sensitivity in mice in the context of a hot/cold test. The authors suggested that myrcene may have an antinociception (anti-pain sensation) effect by influencing the release of endogenous opioids (pain killers).

An additional paper released in 1991 discovered that myrcene has peripheral analgesic effects and that tolerance did not emerge despite repeated treatments. The authors suggest this analgesic effect may give credence to the folk medicine use of lemon grass which is known to be a rich source of myrcene.

These older papers certainly suggest myrcene MAY interfere or influence certain aspects of nociception and pain signalling but what about more recent work?Another intriguing paper using a specific cell line model of osteoarthritis showed that myrcene has significant anti-inflammatory and anti-catabolic effects in human chondrocytes and, thus, its ability to halt or, at least, slow down cartilage destruction and osteoarthritis progression warrants further investigation. As the authors themselves said, this is a very early finding in a specific cell line which won’t necessarily translate to animal models or humans, but it is none the less worthy of continued research effort.

On the topic of inflammation, numerous other papers have shown potential protective effects of myrcene in the context of heart attack and diseases relating to the gut.

This is largely thought to be due to the anti-oxidant and anti-inflammatory properties of the terpene.

Aside from this, one of the most touted potential benefits of myrcene is in the induction of mood and sleep – what does the science say?

Various rodent studies have shown a sedative-like effect with myrcene which includes muscle relaxation, faster sleep induction and longer sleep periods. Another study looking at essential oils extracted from orange peel showed that the extract improved sleep quality of pregnant mothers during the post-partum period. Bear in mind this extract contained myrcene and a host of other terpenes so we cannot determine if the improvements were down to myrcene alone, in combination or not at all.  Aside from these handful of studies, very little research has focussed on myrcene IN ISOLATION on sleep and mood regulation. However, the little bit we do have suggests it is an avenue worth exploring further.

Early results do look promising but as always, we require more clinical evidence before firm conclusions can be drawn about the effects of myrcene on human health.

 Why we use Myrcene

Myrcene is a particularly useful terpene and perhaps the most well-known amongst CBD users and the general public. Not only are there numerous reported/potential health benefits associated with its use (which research which continue to scrutinise), but myrcene imparts a fresh taste to our oils which has hints of cloves and spice. This increased palatability is particularly important to CBD users who don’t like the very earthy and ‘weedy’ flavour that comes with some oils. Myrcene is a major component in the terpene blend of our best-selling Calm oil. 

As always, if you are considering using CBD, gather as much information as you can before making a decision. Take a look at the peer-reviewed research about cannabinoids and terpenes, effects and side-effects on high-quality academic sites like PubMed.