How Strong Is Cannabis Nowadays?

An earlier study, published in the journal Addiction, confirmed that the strength of cannabis had been increasing over the preceding decade. The researchers found that the potency of cannabis had more than doubled across Europe over the period studied.

The study found that THC concentrations in cannabis resin had been stable between 2006 and 2011. However, after then, a rapid increase was seen, with levels rising from 10% to 17% by 2016.

It is thought that the rise in the potency of cannabis resin was mainly a result of new production techniques employed by cannabis producers in Morocco and Europe.

More recent evidence indicates that cannabis potency remains an important issue. According to the European Union Drugs Agency’s 2026 report, the average THC content of cannabis resin seized in the EU in 2024 was 24.6%, compared with 12% for herbal cannabis. These are averages, and the strength of individual products can vary considerably.

So, what exactly is THC?

The cannabinoid known as delta-9-tetrahydrocannabinol, or THC in short, is the main psychoactive compound in cannabis and is responsible for many of its mood-altering effects. The strength or potency of cannabis is primarily determined by the amount of THC it contains, although other cannabinoids can influence its effects. The concentration of THC in cannabis doesn’t remain the same and varies according to various factors such as the strain or plant variety, the way the plant is grown, the methods of preparation and storage, and the part used to manufacture the drug.

Strain and Cultivation technique

As mentioned above, the strength of cannabis depends upon the amount of THC, which also depends upon how the plant is cultivated. Cannabis plants used for herbal cannabis and hashish production can belong to different varieties of the Cannabis genus. Female plants are generally kept separate from male plants to prevent pollination because unfertilised flowering tops, called sinsemilla, can contain high levels of THC. Selective breeding and cross-breeding have also produced newer cannabis strains that contain high levels of THC.

Some agricultural scientists have suggested that cannabis grown hydroponically may be stronger than cannabis grown outdoors. Hydroponics is a method of plant cultivation using nutrient-rich water rather than soil, often in controlled indoor environments. These conditions can allow plants to reach their genetic potential, but hydroponic cultivation does not automatically result in higher THC potency. The strain being grown and the conditions under which it is cultivated are also important factors.

Some cannabis users claim that they can differentiate hydroponically cultivated cannabis because it is particularly strong. However, others disagree with the suggestion that hydroponic cultivation alone produces stronger cannabis. They argue that large-scale hydroponic cultivators may be growing stronger strains under optimal conditions. An Australian study involving just ten plants examined differences between cultivation techniques and found considerable variation in THC potency. This small study did not establish that any particular growing technique consistently produced more potent plants.

Part of Plant Used

As already mentioned, the flowering buds of the female cannabis plant generally contain high levels of THC and other cannabinoids, followed by the leaves. The seeds and stalks of the plant contain very low levels of THC.

Preparation for Use

The cannabis plant is processed in a number of ways, and the method used in preparing the plant directly affects the potency of the cannabis. Hash oil is obtained by extracting cannabinoids from the plant and can contain particularly high concentrations of THC. Its strength varies considerably, and some modern cannabis concentrates contain much higher THC levels than traditional herbal cannabis or resin.

Hashish can also be prepared by collecting and processing resin from the cannabis plant. Historically, resin was often described as containing around 10 to 20 per cent THC, but modern products can exceed this range. Herbal cannabis is prepared from the flowering buds and sometimes the leaves of the plant. Its potency also varies according to the strain, growing conditions and preparation methods.

Cannabis Has Become Stronger?

Some people realise that present-day cannabis has become stronger than it used to be. During the 1970s, there was media coverage suggesting that cannabis was becoming stronger. This is a cause for concern because exposure to higher concentrations of THC can increase the risk of adverse effects. Over recent decades, there has also been growing concern about health problems associated with cannabis consumption, although these cannot be attributed solely to cannabis becoming stronger.

Research published in Addiction has helped establish how cannabis potency has changed over time. The growing health complications might partly reflect changes in the types of cannabis products being consumed and their THC concentrations. The age at which people start using cannabis is also important. Research indicates that frequent cannabis use, particularly when it begins during adolescence, is associated with an increased risk of dependence and mental health problems.

So What’s the Story?

Users who have been using cannabis over long periods of time claim that cannabis has become stronger over the years. The available evidence does indicate that the potency of cannabis has increased substantially over recent decades. However, this does not mean that all cannabis products have increased in strength by the same amount, or that cannabis is universally 30 times stronger than it used to be. The type of product, its THC concentration and the amount consumed can all affect exposure to THC. Frequency of use, the test employed and individual factors can also affect how long cannabis stays detectable in your system.

The age at which cannabis users start using the drug, and the type of cannabis being consumed, make an important difference to the story. Flowering buds of female cannabis plants generally contain higher concentrations of THC than leaves. Consumption patterns have also changed over time, with cannabis being smoked, vaporised or consumed in other forms. The amount of THC absorbed depends on the product, its strength, the quantity used and the method of consumption.

The age at which cannabis users start taking the drug has become a very important aspect in understanding cannabis-related harm. When people start at a very young age, they may face additional risks, particularly if their use becomes frequent or continues over a long period. Simply focusing attention on the potency of the drug might dilute the attention required to understand the wider problems associated with the age of first use and patterns of cannabis consumption.

Detecting Cannabis with a Urine Drug Test

Cannabis drug testing kits from Zoom Testing offer a convenient way to screen urine samples for THC metabolites. Urine cannabis tests generally detect THC-COOH, a metabolite of THC, rather than measuring the strength of cannabis consumed or establishing current impairment. For more information on cannabis drug testing, check out our Cannabis Drug Testing FAQ.

These tests provide an initial screening result, often within a few minutes, depending on the kit being used. Accuracy, cut-off levels and detection windows vary between tests. A non-negative screening result should be confirmed by an appropriate laboratory method where the outcome could have significant medical, legal or employment consequences.

Zoom Testing offers cannabis urine drug testing kits for convenient home screening. Orders are supplied in discreet packaging.

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