What is Cannabis? A Beginner's Guide

What is Cannabis? A Beginner's Guide

Cannabis is a fascinating plant that has played many roles in society, from a celebrated medicine to a feared and outlawed drug. 

The growth in cannabis’ legality and popularity over the last decade has meant the global consensus around cannabis has become more positive. With all this change around how cannabis is viewed and the complicated science around it, you may find yourself confused about what exactly cannabis is and what it does. 

So, here is everything you need to know about cannabis to help you make up your mind about this plant. 

What Is Cannabis? 

Cannabis is the formal term for what is often thought of as the medical or recreational herb whose consumption can induce psychoactive effects. 

However, there’s a lot more to cannabis than the ‘high’!

Cannabis’ use in popular culture has given rise to many nicknames - weed, marijuana, skunk, grass, dope, ganja, chronic - all of which refer to the same plant.

In botanical terms, Cannabis is a flowering and dioecious herb that is classified as a genus under the Cannabaceae family - this family also includes Humulus, such as hops, and Celtis, such as hackberries.

Within the Cannabis genus, botanical taxonomists continue to dispute how many species exist. Most leading researchers consider Cannabis sativa as the single species, with three subspecies beneath it.

Sativa vs Indica (vs Ruderalis)

There are three subspecies of cannabis, two of which you have likely heard of: Cannabis Sativa and Cannabis Indica and a third which is less well known: Cannabis Ruderalis. These subspecies are distinguishable by their physical expressions, from leaf colour and shape, to how tall they grow and the density of their branches.

It’s worth noting that:

Almost all commercially available cannabis, be it medical or in countries where recreational cannabis is legal, is actually a hybrid of the above subspecies. A hybrid is when different subspecies are cross-bred to attain desirable traits from each, most hybrids combine an indica and sativa, so are thought to fall somewhere along the indica-sativa spectrum depending on parental lineage.

There are very few pure indicas or sativas available on the commercial market.

So, what about the effects of sativa vs indica?

One of cannabis’ most common misconceptions is that sativas offer an uplifting ‘head high’ where indicas result in a sedating ‘body high’. Many consumers and even some companies continue to use this terminology. Not only is this inaccurate since most strains are hybrids but rather it is a plant’s chemical profile that dictates effects, not its physical traits.

“There are biochemically distinct strains of Cannabis, but the sativa/indica distinction as commonly applied in the lay literature is total nonsense and an exercise in futility.

One cannot in any way currently guess the biochemical content of a given Cannabis plant based on its height, branching, or leaf morphology. The degree of interbreeding/hybridization is such that only a biochemical assay tells a potential consumer or scientist what is really in the plant.”

- Dr. Ethan Russo, International Cannabis and Cannabinoids Institute

So the indica vs sativa argument is a bit of a waste. Those words simply refer to the physical traits of the cannabis plant, not the compounds that actually impact how someone would feel if they consumed the different types of cannabis.

To understand what effects a particular strain of cannabis will have, we need to look at its chemical composition.

Plant Chemistry - Cannabinoids, Terpenes and Flavonoids

There are three main groups of chemical compounds in cannabis, all of which interact differently with the human body and with one another.

Those compounds are called cannabinoids, terpenes and flavonoids.

And it’s the different combination of these compounds that give each cannabis strain its unique health benefits and psychoactive effects. 



Cannabinoids are one of the most prevalent chemical compounds in cannabis, and over 100 cannabinoids have been discovered to date (upu to 121 by some estimates). They are the priimary active ingredients in cannabis that produce a wide range of effects.

The two major cannabinoids, THC and CBD, are present in higher levels in most cannabis strains and have demonstrated significant effects in the human body.


Tetrahydrocannabinol (THC)

THC, also known as tetrahydrocannabinol, is the most well known cannabinoid as it is responsible for the intoxicating ‘high’ of cannabis.

THC induces its psychoactive effects on the body by binding to the cannabinoid receptor CB1. Some short-term effects of THC can include elation, relaxation, energy, hunger, drowsiness and memory impairment.

However, THC does more than just produce a high. 

In fact, THC has also demonstrated significant therapeutic potential with studies highlighting its ability to reduce pain, inflammation, and the symptoms of PTSD


Cannabidiol (CBD)

CBD is the other main cannabinoid in cannabis. Unlike THC, CBD cannot induce any intoxicating effects and is thus often referred to as non-psychoactive (though this is technically incorrect since it does interact with the brain).

CBD actually counteracts intoxication caused by THC and can therefore be used to nullify THC’s side-effects.

So why is CBD so popular if it doesn’t make people high?

CBD has gained a reputation for its therapeutic potential alone. The possible therapeutic benefits of CBD include better sleep quality and a reduction in pain, inflammation, and anxiety. There are also pharmaceutical CBD products that have been approved by healthcare regulators around the world for the treatment of epilepsy.

CBD exerts these effects on the body a little differently than other cannabinoids. CBD can only weakly bind to cannabinoid receptors in our body, so it binds to non-cannabinoid receptors and acts on other receptor pathways. 



Terpenes are produced by a variety of plants, often to lure pollinators, deter herbivores or otherwise attract herbivore predators. 

Terpenes are the compounds that give cannabis its aromatic and flavour profile. They  are secreted through cannabis’ sticky resin glands, which also produce its cannabinoids. Because of their role in scent, terpenes are often named after the specific smell they create. For example, pinene is responsible for the distinctive smell of pine trees. 

But the scent is not the only thing terpenes are known for. They have also been found to induce various health effects, especially in conjunction with certain cannabinoids.

The cannabis plant contains over 200 different terpenes, but there is a generally accepted “Major Six”:



Flavonoids are compounds that can be found in many plants, fruits, and vegetables and are mostly responsible for colouration. For example, they help produce the blue in blueberries and the red in raspberries. These small compounds are also found in cannabis and have demonstrated strong antioxidant activity too.

Antioxidants help to prevent the cell damage caused by free radicals, allowing your cells to stay healthier and function better.


The Entourage Effect

As we’ve touched on here, cannabis contains hundreds of different chemical compounds, many of which have specific healing attributes. Importantly, these compounds are also able to interact synergistically with each other in what is known as the ‘entourage effect’.

It is believed that when the compounds are combined, their therapeutic impact is enhanced. That is to say, the benefit of the whole plant is greater than the sum of its parts. 

This is the reason why isolate products are generally accepted as not offering the same benefits as whole plant extracts.


What is Hemp?

Another confusing aspect of cannabis is its association with  hemp.

Though hemp is legally considered a distinct entity from cannabis, it is technically just a variety of Cannabis Sativa. Its defining property is a maximum THC threshold of 0.2%-0.3%, depending on which country you live in. In the UK for instance, it’s 0.2% whereas it’s 0.3% in the US.

So if a cannabis plant contains less than 0.2%-0.3% THC it can technically be called hemp.

Given the minimal THC levels in hemp, it follows that hemp has no potential intoxicating effects. This difference in chemical compounds is why CBD products are often legally required to be extracted from hemp, in order to minimise any risk of THC contamination. 


Is Cannabis Legal? 

Cannabis legalisation is slowly becoming more and more prominent across the world, and its legal status depends on where you are located. 

In the UK, cannabis is only legal when prescribed by a specialist physician for specific conditions such as certain types of childhood epilepsy, vomiting or nausea caused by chemotherapy or muscle stiffness and spasms caused by multiple sclerosis. 

However, CBD extract is legal as long as it is derived from a hemp strain that contains no more than 0.2% THC. 

In the US, cannabis’ legal status is slightly more confusing. Cannabis is illegal federally, but many states have legalised the recreational use of the plant, including California and Colorado. 


The Bottom Line 

Cannabis is a complicated plant with a long history.

Cannabis can get you high, but it can also potentially offer a range of health benefits. Views and opinions of cannabis have come a long way in the last few decades and today extracts like CBD are readily available and even legal, depending on where you live.

With growing research, it seems that there are only more exciting things to learn about this plant.