Cannabinoid degradation & storage
Does my medical cannabis go off?
Expiry dates and storage instructions are part of medicine quality, not decoration. Cannabinoids and volatile compounds can change over time, and the exact stability depends on the supplied formulation and packaging.
Time and conditions can change the chemistry.
THC can degrade over time and CBN can form as a degradation product. A four-year study found that storage temperature and light exposure affected this conversion differently. Terpenes and other constituents can also be lost or altered during post-harvest handling and storage.
“Cool, dark and airtight” is a useful principle—not a replacement label.
Reducing unnecessary exposure to light, heat and air generally supports stability, but different products have specific packaging and temperature requirements. Follow the dispensing label, manufacturer information and pharmacist advice for the exact medicine. Do not refrigerate or freeze a product unless its instructions support that.
Keep the original packaging.
The supplied container protects the product and carries the dispensing label, patient identity, directions and other traceability information. Moving medicine into an unlabelled jar can lose that evidence and may expose it to unsuitable conditions.
An expiry date is not a home potency test.
Appearance or smell cannot establish cannabinoid strength, microbiological quality or whether a medicine remains suitable. Do not try to compensate for an old or poorly stored product by changing the amount used.
Tell the dispensing pharmacy what happened, for how long and which product is involved. The pharmacy or supplier can advise on the specific stability information available.
Dispose of unwanted medicine safely.
Keep expired or unwanted medicine secure until it can be returned through an appropriate community-pharmacy disposal route. Do not share it, leave it accessible or put it into household wastewater.
Primary sources
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