For as long as people have been using cannabis recreationally, governments and the media have pedalled scare-mongering tactics in an attempt to control them. This has arguably been demonstrated most effectively in Western countries – particularly in the US where the ‘War on Drugs’ really ramped up in the 60s and 70s. Over the decades, we have been repeatedly warned of the increasing potency of weed, but do the numbers really stack up?
We’re analysing figures from the ‘reefer madness’ days of cannabis to modern ultra-potent skunk to find out: Is cannabis really 67,200 times stronger today?
This figure might sound a little far-fetched, but according to old media reports highlighted in a recent article (and accompanying video) by Dana Larson, it does check out. Of course, this figure should still be taken with a pinch of salt, as many of the sources cited are simply individuals with an axe to grind, with very little actual evidence in sight.
Yet, the fact remains that we are consistently informed of the increasing strength of cannabis and warned of the dire implications this can have on our health. So, let’s take a look at the evidence to find out how much stronger weed really is today than the herb your parents, grandparents, and maybe even great-grandparents were smoking back in their day.
What is the average strength of cannabis in the UK today?
In recent years, there have been countless reports in all the country’s biggest newspapers about the soaring strength of street cannabis. A 2020 report in the Guardian quoted research from the University of Bath indicating that the THC concentration in cannabis resin, or ‘hash’, increased by nearly 25% in the last five decades – an average THC increase of 0.57% each year. Meanwhile, in the same period, THC concentrations in herbal cannabis were reported to have increased by a relatively less significant 14% – an average THC increase of 0.29% per year.
The figures were based on data from more than 800,000 street samples from the UK, the US, the Netherlands, France, Denmark, Italy, and New Zealand over a 50-year period (1970-2017). They included a total of 12 articles in their systematic review and meta-analyses, the majority of which (5) were based in the US. Most studies assessed seized illicit cannabis material while the two included Dutch studies analysed samples purchased directly from retail outlets.
Unfortunately, the only UK-based study included in the review only covered imported cannabis products between 1985 and 1989. However, another more recent study may provide more answers.
The rise of ‘dangerous’ Skunk
Skunk is a term that UK newspapers, police forces and even the UK government like to throw around a lot. It is usually mentioned after terms such as “super-strong” or “high-potency”, but what does it actually mean? Well, most of the time, it is used as a catch-all for buds that have been grown from plants bred to produce seedless cannabis flowers.
Unfertilised female cannabis plants are known to produce much higher levels of THC than male or fertilised female plants – a fact discovered by Mexican growers in the 1970s where these plants were originally called sinsemilla (Spanish for without seed). Female, unfertilised plants produced higher yields and, as such, cultivators increasingly began to prioritise these plants.
Skunk was the name given to just one of many strains of cannabis cross-bred to produce plants with the genetic ability to produce more THC in the 80s and 90s. It’s unclear why the media latched onto this particular strain as a catch-all for strong weed, and while it is often used in a way to portray ‘dangerous’ high-strength cannabis, it was used to produce Sativex – a cannabis spray licenced for use on the NHS.
A change in consumer habits?
Cannabis flowers that are traditionally stronger in THC have all but knocked the relatively low-THC alternatives, such as hash and non-sinsemilla (or “traditional”) herbal cannabis, out of the UK market. According to police records from 2016, “skunk” accounted for 94% of cannabis seizures, compared to 85% in 2008 and 51% in 2005. The authors of the study – researchers from King’s College London – note that the average potency of the “skunk” analysed was around 14% THC.
In comparison, the cannabis products tested between 1985 and 1989 – a time when traditional herbal cannabis and hash likely accounted for the bulk of the market – had an average potency of around 4-6%.
The figures laid out here indicate that, in the UK at least, illegal cannabis products have probably increased in potency by around three times – a far cry from the figure mentioned at the beginning of this article, but what about in the rest of the world – or more specifically, across the pond?
Is cannabis getting stronger in the US and Canada?
With ongoing legalisation in North America, including outright legalisation in Canada and almost half of US states, it’s fair to say that stoners over there probably have more choice than most of us Brits. So maybe they really are smoking weed that’s 62,700 times stronger than the supposed dust of the 1930s?
Well, to put it simply: No. Of course, just as in the UK and the rest of Europe, cannabis in the US and Canada has increased in potency, and is often even stronger than the street cannabis over here. Analyses of 38,681 cannabis samples seized by the DEA in the US between 1995 and 2014, reveal that cannabis potency has increased from around 4% to 12%. Surprisingly similar to the UK figures.
However, according to a 2020 study of advertised THC concentrations in medical and recreational cannabis products from legal dispensaries across five cannabis legal states, most Americans might actually be consuming much stronger products.
The researchers assessed the advertised potency of medical and recreational cannabis products as listed on dispensary websites. They found that the average potency of medical cannabis was in fact 19.2%, while recreational products were slightly stronger at 21.5%. That’s around five times stronger than the illicit cannabis seized by the DEA thirty years ago.
And yet, things still might not be as simple as they appear. In fact, legal cannabis products in the US, which are legally required to display their THC content, may actually be weaker than advertised.
Is it all smoke and mirrors?
A 2023 analysis of cannabis flower sold in dispensaries in four US states – highlighted by MJBizDaily – indicates that advertised THC concentrations are being “routinely and systematically inflated”, sometimes by as much as 25%. The analysis was performed by Yasha Kahn of MCR Labs, a state-licensed cannabis testing laboratory in Massachusetts, and also revealed potential data manipulation in lab testing for mould and yeast.
This finding directly contradicts one of the key arguments made for cannabis legalisation: better assurances regarding the safety and contents of cannabis products. Moreover, it makes things even less clear when trying to compare the potency of modern cannabis products with the weed of the past.
Why does cannabis potency matter?
Despite a long history of medicinal use and a growing body of evidence supporting its therapeutic potential, cannabis still gets more than its fair share of bad press. Unfortunately, most of this is directly related to the effects of THC. While this intoxicating, psychoactive compound has a number of impressive therapeutic properties, its negative side effects – such as anxiety, cannabis use dependence, and potential links to psychosis – tend to garner much more attention.
Importantly, sinsemilla cannabis – which rules the market today – tends to have a higher ratio of THC to cannabidiol (CBD). CBD is a non-intoxicating cannabinoid that, despite rising in popularity in recent years, is becoming increasingly scarce in recreational cannabis products. Some studies indicate that CBD may be effective at reducing the negative side effects of THC, such as intoxication, anxiety, and even psychosis.
It is clear that consumer habits are changing and cannabis has indeed increased in potency over the years, though perhaps not by the sensationalist margins historically cited by governments, police, and tabloids.
