I think it’s fair to say that most of us would be a little apprehensive at the thought of eating food that has been blasted with radiation. It isn’t something I’d personally (or knowingly) want to do. But, surprisingly, it’s a pretty standard procedure here in the UK. The same goes for cannabis; nearly all medical cannabis available in the UK has undergone an irradiation sterilisation treatment. Though this may sound off-putting, spoiler alert: irradiation does not cause radioactive weed.
Irradiated cannabis dominates the medical cannabis flower market in the UK. At the time of press, only 6 out of 36 strains showing as available to patients on Medbud are non-irradiated, and its prevalence in the UK medical cannabis industry is causing quite a stir. Some patients believe that the taste, quality, and effectiveness of their medicines have been compromised by exposure to radiation. Is there any truth in this? leafie takes a look at the latest research.
What is irradiated cannabis?
During cultivation, cannabis goes through a “curing” process, in which the flower is dried over a long period of time. This process, if not conducted properly, can cause potentially harmful microbes to accumulate, so many manufacturers use ionising radiation to eliminate these contaminants. And that’s simply what irradiated cannabis is; it has been zapped with gamma radiation to rid the flower of bacteria and mould.
According to a paper published in Frontiers in Plant Science in 2019, common plant pathogens can stunt the growth of the cannabis plant and reduce product quality. For immunocompromised medical cannabis patients, such as those undergoing cancer chemotherapy, pathogens could potentially cause life-threatening infections. Irradiated cannabis is, therefore, the safer and preferred treatment option for more vulnerable patients.
The irradiation process
As daunting as it sounds, irradiation is actually a relatively common decontamination technique in food production – and has been for over thirty years. Many household food products in the UK are now likely to have undergone irradiation, including common fruits, vegetables, fish, poultry, and spices. Although regulations usually state that radiation levels should be kept as low as possible, it is an often necessary step for products to satisfy food production safety requirements and eliminate microorganisms and pathogens.
Since the UK legalised cannabis-based medicines in 2018, it has become standard practice for clinics to prescribe irradiated cannabis to patients. This is because “it has yet not been possible to grow cannabis plants under sufficiently sterile conditions to keep contamination levels below the required safety limits,” say the authors of a paper published in Frontiers in Pharmacology in 2016.
Irradiation works differently from chemical decontaminants in the sense that it, allegedly, does not alter the plant’s chemical composition. Instead, when the plant is exposed to gamma rays, a highly energised form of ionising radiation, it damages the DNA of microbes. This prevents their growth and, in turn, causes these potentially harmful pathogens to perish.
Though, despite this process being marketed as a necessary step to meet safety standards and reduce health risks to patients with compromised immune systems, irradiated cannabis has sparked considerable debate among UK medical cannabis patients.
Concerns from cannabis patients
The reluctance to consume what sceptics call “nuclear weed” feels rational. With Chornobyl and Hiroshima, radiation certainly has pretty catastrophic connotations, so the premise is bound to seem alarming. However, the key thing to address here is that irradiated cannabis is safe to consume. And since the cannabis plant has a very low-fat content, there is very little risk of gamma irradiation causing the formation of harmful, radiolytic compounds.
So, blasting cannabis with radiation isn’t a bad thing – medically speaking, at least. But there is some conflicting evidence surrounding whether this irradiation step compromises the quality of cannabis medicines.
One study, conducted by Dr Arno Hazekamp and published in Frontiers of Plant Science in 2016, analysed various cannabis strains before and after it was treated with gamma radiation. Hazekamp noted no significant changes to levels of THC or CBD, but terpene levels were reduced by about 10-20%. In some cannabis samples, this figure was as high as 38%.
Discussions on social media make it clear that most patients simply prefer consuming non-irradiated cannabis. Some find that these supposed terpene reductions alter its flavour, whereas others find the cannabis medicine itself is less effective. And there may be some truth behind this.
Discussions on social media make it clear that most patients simply prefer consuming non-irradiated cannabis. Some find that these supposed terpene reductions alter its flavour, whereas others find the cannabis medicine itself
Terpenes have been shown to activate CB1 receptors and enhance cannabinoid activity, as well as enhance the potency of cannabinoids; this is a widely-accepted theory, known as the “entourage effect”, which states that cannabinoids work better in combination with terpenes. There is, therefore, reason to believe that disrupting the terpene content of whole-plant cannabis could reduce its therapeutic effectiveness.
That said, there is currently no evidence that the irradiation process reduces the quality or effectiveness of medical cannabis. Although one study, published in Biocatalysis and Agricultural Biotechnology in 2020, noted that irradiation increased the cannabinoid content of cannabis flower, changed terpene levels, and subsequently altered its effect on cancer cell cultures, far more research is needed before researchers fully understand the effects of irradiation on the medicinal properties of cannabis.
Whilst we can say for certain that irradiation treatment is safe, its effects on the quality remain unclear. What is clear is that many UK patients have a preference for non-irradiated cannabis. If clinics genuinely want to help patients move over from the black market, they need to give them the right to choose whether their medicine has undergone the irradiation process.
All those in favour
Despite the backlash, not everyone is opposed to irradiated medicines. One Reddit user, who uses cannabis to manage the symptoms of IBS, claims they “would rather not have mould and bugs in [their] weed. The bugs aren’t too bad, but the mould [or] fungus can be deadly.”
Another user believes that the debate has been overblown. “I’ve had both and I’m not convinced on the big difference,” they write in response to a post in the r/ukmedicalcannabis subreddit. “I’ve found far greater variations in different growers and their strains, regardless of their state of irradiation, than I have between irradiated and not.”
Since the option to choose between irradiation and non-irradiated cannabis is rarely offered, it is unlikely that patients have been able to make a direct and reliable comparison between the two. It may be there are other factors – the cannabinoid content or cultivation process, for instance – that influence how well a person reacts to a cannabis product.
Though, ultimately, the voices of the patients should be heard. Whilst irradiation is a necessary safety precaution for some conditions, if patients were to be offered the choice between whether their medicine is irradiated or not, this would likely shift interest away from the illicit market and to the clinic – arguably offering even safer access to treatment.
