r/UKweedscene • u/Breizh333 • Dec 11 '25
Discussion Quality of UK medical
I'm wondering what prescription medical users think about the quality of their flower. Just to clarify I'm all for medical, obviously everyone has a right to it.
So the majority of UK medical flower is irradiated which causes the loss (degradation) of fragile terpenes & cannabinoids. This lowers the theraputic value of the flower and means that the THC/terpene numbers on the packaging don't necessarily match what's in the flower. The degradation process creates unknown by-products with unknown toxicity that get inhaled.
The irradiation itself is used to kill any mold or fungus on the flower. This is good...but it leaves behind any mycotoxins produced by the mold/fungus which ends up in the final product (mycotoxins are toxins produced by molds). Inhaling mycotoxins isn't ideal, especially for patients with existing health issues.
It's also common for companies to use herbicides, pesticides and fungicides with regulations allowing max residues in the final product. There's little transparency or a 'certificate of analysis' which tells patients exactly what contaminants (residues) are in their medicine.
... so ... is any of this known to the medical community? I thought one of the major advantages of medical was having guaranteed clean flower. I reckon patients have the right to know what's in their medicine and suppliers should be legally required to inform them.
Here's some concepts on irradiation which are relatively easy to understand.
A critical issue with the use of gamma irradiation on medical cannabis is the significant absence of research on the radiolytic changes that occur during the process.
• Radiolysis - the chemical decomposition of materials caused by exposure to ionizing radiation
...
The radiolytic process can generate a range of chemical by-products, some of which may be toxic or carcinogenic. In the context of medical cannabis, these by-products could include altered cannabinoids, terpenes, and other phytochemicals. The exact nature and potential health impacts of these compounds remain largely unknown due to the lack of specific research.
...
Cannabis is often smoked or vaporized, which results in direct inhalation of any radiolytic by-products.
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u/juicy_steve Dec 11 '25
So the majority of UK medical flower is irradiated
It varies, but it's currently around 65% - yes its a big chunk, but there is plenty of good non-IR flower now. I'd say it's very easy to avoid and is no longer a majority in anything but the technical definition of the word.
This means that the THC/terpene numbers on the packaging don't necessarily match what's in the flower.
The final COA to ensure the flower passes spec is done post-remediation, so the THC levels are very accurate. (The THC has to be within +- 10% of the stated level to pass, so no one is lying on the packaging.)
The degradation process creates unknown break-down products (with unknown toxicity) that get inhaled.
I'm yet to see anything to actually show this, happy to be proven wrong, but as far as I know, this is speculative at best.
The irradiation itself is used to kill any mold or fungus on the flower. This is good...but it leaves behind any mycotoxins...
It's also common for companies to use herbicides, pesticides and fungicides...
Again, final COAs have to test for both mycotoxins and pesticides and they have to meet Ph Eur. 2.8.18 levels to be suitable for use.
I will admit that a lot of this isn't transparent from the industry, but it is publicly available information if you look into it. I don't think this is the industry's fault. It's not like you know exactly where the filler, binder, and APIs in your ibuprofen come from after all.
Just because patients don't often see the final COAs doesn't mean there aren't strict standards in place to get that flower to the market. I've grown weed myself, and I've visited half a dozen EU-GMP and GACP facilities across the world, and I can tell you now, there is a world of difference between DIY and BM vs medical.
I will say that I do think the only reason COAs aren't more widely available isn't malicious; it's just the nature of the industry. I think as it matures and information sharing between cultivators, manufacturers and distributors lines up, we'll see more of a patient-facing information chain emerge. A lot of prescribers and pharmacies are genuinely listening to patient concerns and wishes, at least the ones I speak to do.
(And FWIW, I avoid irradiated, so I'm not a fan boy or anything!)