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Irradiated cannabis – what you need to know

As part of the ongoing fight against pathogens, more cultivators are turning to irradiated cannabis as a means to stave off fungi and bacteria. Irradiation (the act of exposing the plant to radiation) may sound dangerous and even scary – but is it?

Nuclear technology is perhaps one of the most maligned industries today. Its reputation has been understandably tainted by a few high-profile examples of leaks and disasters, such as Chernobyl or the more recent Fukushima plant – but despite these well-known incidents and potential hazards, nuclear tech has a lot to offer. In many countries, food irradiation has existed for decades and encompasses various foods, including fruits, root vegetables, fish and fresh meats[i]. At present, around 60 countries worldwide utilise irradiation to ensure quality in their food supply[ii].

In a 2018 interview with the Winnipeg Free Press, Dan Sutton, founder and CEO of Canadian licensed cannabis producer Tantalus Labs, stated that he had been researching the use of irradiation in the medical cannabis industry and suggested that the technique had been used by at least 80 per cent of legal cannabis producers[iii]. With a career background in the nuclear fuel industry, Sutton is well-positioned to gauge the safety of irradiation treatment, and, with Canada’s medical cannabis regulations at the pinnacle of the safety standard worldwide, this would at least seem to vouch for irradiation as a safe, viable method of cleaning crops.

How it’s used

In cannabis irradiation, the cannabis is loaded, a few pounds at a time, into a machine resembling a large microwave oven, then subjected to a blast of gamma rays from a synthetic cobalt isotope. The same technology is used to sterilise food and medical equipment[iv] – which would certainly appear to affirm its safety. The process of exposing cannabis to gamma rays has the effect of inactivating numerous contaminants, including the more challenging microbes encountered by cultivators, such as mould and powdery mildew. Dan Sutton succinctly explained the process in a series of tweets on the subject in March of 2018, where he stated irradiation involved “…using energy to shake DNA bonds in mould and other pathogens to render them inert”[v]. In other words, effectively sterilising the plant.

Is irradiating cannabis safe?

Despite its approval rating, cannabis irradiation appears to maintain a divisive status in many quarters. The Organic Consumers Association claims that irradiation can cause the loss of 85% of vitamins and damages natural enzymes in foods[vi]. So what does it mean for cannabis?

Although concerns have been raised, including changes to texture, flavour, and terpenes, research published in the journal Frontiers in Pharmacology did not show any THC, CBD, or moisture content changes. Some terpenes, however, are shown to change – namely myrcene, ocimene and terpineol – with the research suggesting a reduction of between 10 and 20%, but for some components, this may be as much as 38%[vii]. That’s a big chunk of change. Do you want to buy cannabis with a 38% reduction in terpenes?

However, the study also noted that the degradation was not the same for each strain, and some strains did not show any degradation effects. Arno Hazekamp, Head of Research and Education at Bedrocan BV, went further to allay fears, saying, “Some terpenes have a somewhat reduced content because they somehow evaporate during the irradiation procedure.

However, no new compounds or degradation products were observed.”[viii] To expand, changes occur at the terpene level but are not detrimental to the potency of the cannabis and do not damage the product. Dan Sutton added, “Most arguments against irradiation suggest that cannabis goes into the process spongy, odorous and beautiful, and comes out crispy and burnt. This is patently untrue. Crispy weed happens in rushed drying and finishing processes, and a lot of that product happens to be irradiated”[ix].

Despite this, some remain highly sceptical; insisting irradiation causes a different flavour or different effects due to a change in the plant’s biochemical makeup. And since terpenes have been shown to offer medical benefits, such as myrcene’s anti-inflammatory properties, any change at all is understandably seen by many as something to be avoided. Therefore, one is left with the choice of either opting for irradiation as a guaranteed method of pathogenic prevention or bypassing the method completely to maximise the benefits and desirable qualities of cannabis.

Can you tell if cannabis has undergone irradiation?

If you’d rather avoid irradiated weed, there are things you can look for which may point to a plant that has been through the experience of irradiation treatment. First off, cannabis from a medical dispensary is more likely to have been irradiated – as Dan Sutton said – an estimated 80% of LPs in Canada are using the method. With dispensaries in the USA and the Netherlands following suit, there’s a strong likelihood that dispensary weed will have been treated this way. With WHO approval of the method and the guarantee of good pathogen resistance, it makes sense that mass-produced cannabis will undergo the process. But is there a way to tell?

Some users report a noticeable lack of glandular trichomes, fluffy or brittle buds and a reduction in flavour. This is consistent with a reduction in terpenes and seems like more than a small price to pay.

It’s a matter of weighing up the pros and cons – on the one hand, irradiated cannabis will ensure large quantities of commercial cannabis will be free from pathogens, but if there’s any cost in terms of flavour or benefits via reduced terpene content, then you might want to nuke that idea.






 [v, ix]


[vii, viii]

Cultivation information, and media is given for those of our clients who live in countries where cannabis cultivation is decriminalised or legal, or to those that operate within a licensed model. We encourage all readers to be aware of their local laws and to ensure they do not break them.

This post is also available in: French

Duncan Mathers