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Maxing out: has cannabis reached its potency limit?

There’s no getting around it: cannabis has never been stronger than it is today. But could tomorrow’s marijuana be even more potent or are we about to reach a plateau with maximum CBD and THC levels? We thought 20 percent THC was staggering, but the Chiquita Banana strain has gone even further, testing at over 30 percent THC. Tetrahydrocannabinol (THC) is the most important psychoactive component in marijuana and creates the necessary reactions for us to get “high.”

Growers are split on whether THC and CBD-dominant cannabis can get much more potent. Some cultivators continue to diligently crossbreed strains in effort to up the strength, however an article on the highly-respected Leafly website argues that we’re close to the limit.

Cannabis is an incredibly complex plant, with some strains consisting of more than 400 unique compounds – more than 100 of them are only found in cannabis and are known as cannabinoids. THC and CBD are the primary cannabinoids in marijuana – THC has medicinal and recreational uses, while CBD is only suitable for therapeutic use. While others do show medicinal potential, they simply haven’t been studied sufficiently yet.

Society tends to focus on the hallucinogenic effects of marijuana, which comes mainly from THC. High-THC strains are generally thought of as recreational, but they do in fact have medicinal effects too – THC is, for instance, a powerful anti-inflammatory molecule.

Until the past few years, CBD has gone under the radar, but its success as a treatment for medication-resistant pediatric epilepsy brought the compound to national media attention. CBD’s big breakthrough came when the cannabinoid was the center of a medical cannabis documentary made by CNN called Weed.

Cannabis growers have managed to eke THC concentrations above 30 percent in the most THC-rich strains. In contrast, the most potent CBD-rich strain contains around 23 percent CBD. For the THC strains, 30 percent means that nigh on one-third of the entire herb is made up of the psychoactive compound. What other chemicals feature in cannabis? Proteins, fibers, sugars and fats make up a significant portion of the plant.

And it’s these proteins, fibers and plant matter which prevents THC levels from totally dominating the plant. Since these components are all necessary to make the herb, it’s simply impossible for strains to be made with 70 to 80 percent THC. Furthermore, the 30 percent THC strains we do know about aren’t exactly commonplace. Most strains classed as high-THC will have between 17 to 25 percent of the cannabinoid.

However, if you are looking for such extraordinary potencies, concentrates have you covered. Crystal isolate products can consist of 99 percent CBD or THC, making them the purest cannabis products in the world.

Is THC and CBD potency nearing its limit?

Therefore, as we cannot grow a plant that is four-out-of-five parts THC, then the question begs of just how strong cannabis can actually get. The media love to talk about the increasing potencies of street cannabis, but if it’s true and the herb has indeed reached its potency peak, these fears are misguided.

On average, around 30 to 35 percent of a cannabis plant will be made up of cannabinoids. Therefore, plants with lots of cannabinoids are genetically less likely to produce a strain of ground-breaking potency.

Cannabis genetics means that a strain is dominant in THC or CBD, or has a one-to-one mix of both cannabinoids, with the total weight of the cannabinoids maxing out at about 33 percent of the overall plant weight. Genetics also influence whether a strain will produce some of the lesser-known cannabinoids.

Scientists have proposed that the cannabis plant has three unique chemical phenotypes, or chemotypes. The abilities that a chemotype inherits determines what biochemicals it is able to make. Hence the chemotypes in marijuana play a key role in the cannabinoid profile of a strain, such as which compounds are present and what concentrations those compounds are found in.

The chemotypes are: high-THC cannabis, high-CBD cannabis (hemp) and one-to-one cannabis. You’ll find the high-THC and one-to-one marijuana at recreational dispensaries, while high-CBD strains are rarer and most common in medical circles.

High-THC, low-CBD strains are by far the most popular in America at the moment, with the recreational boom leading cannabis thrill-seekers to try out stronger and stronger strains of psychoactive marijuana. When producing a top-shelf psychoactive strain, growers look to produce high quantities of THC, and a good profile of other compounds, such as terpenes – myrcene is a useful terpene for breeders, as it promotes THC absorption.

Many marijuana growers have turned their eyes to CBD-rich strains as they try to meet the rapidly-expanding demand3, which has come almost entirely since 201. The consensus seems to be that the early-20 percent region is about as potent as CBD-dominant cannabis going to get for the time being.

Most dispensaries have a very limited range of high-CBD strains, if they even stock them at all. Part of this is because high-CBD cannabis is often not consumed as flower but is extracted into oils (tinctures and CBD vape juices), edibles, creams and other forms. Products made with hemp cannabis that have less than 0.3 percent THC are legal everywhere in America, even in states that haven’t introduced explicit medical cannabis legislation. Hemp-based CBD products are also available in many countries that are yet to enact cannabis reform.

So, how do we know if we are maxing out on THC and CBD levels? Experts have zoned in on two key factors: the environment and selective breeding. These have a massive effect on the potency of a strain. Here’s why.


Genetics are essential, but if not grown in the correct conditions, there’s no chance of a cannabis strain becoming a world-beater. Even strains with a reputation for hitting the high concentrations will struggle to perform at their best in an unsuitable environment.

The chemotype and phenotype often has a say on the optimum growing conditions for a strain. Dry climate, high-quality lighting and warm surroundings are necessary for all plants, but it gets a bit more nuanced beyond that.

Cooler evening temperatures are important for some plants – this is just due to how they have adapted. Some strains are more sensitive to light than others, and hence need more care than others.

But a strain without the right genetics will never produce higher cannabinoid potencies, even if cultivated in the world’s best growing conditions. A good environment simply affords the plant the tools it needs to maximize its THC or CBD output.

Therefore, as we go in search of new potency heights, we should remember that genetics only let us go far. At some point we’ll max out.

Selective breeding

Selective breeding has facilitated the growth of increasingly potent marijuana strains. Cultivators’ development of the plant has been severely stifled due to cannabis prohibition, which has gone on in the United States for more than 80 years. However, the most determined breeders have still managed to bring the right strains together, so they can be crossbred to produce new, more potent offspring.

Final thoughts

If you’re thinking about breeding your own cannabis plants, and have ambitions to make extraordinary cannabis, the best place to start is by picking a strain with conducive genetics – this applies for both high-THC and high-CBD plants.

The cannabinoid profile of a strain will be decided by genetics, and if you can start off with a strain that tends to make more of the cannabinoid you need, then it may be great to grow with. Do your own research for your specific cannabis interest before buying seeds or clones.

Or perhaps you want to grow one-to-one cannabis, with the aim of developing a strain that has a perfect balance of CBD to THC. Consider starting with a seed or clone from a strain that has a reputation for producing the compounds you’re after.

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