Does Weed Expire?


The Canadian government wants legal pot is sold in plain packaging with scant black and white graphics, lab data, and expiry date, prompting one question. 

Weed’s expiry date depends on the cannabis you buy and how you store it. Dry marijuana flowers have more of a “best before” date, ensuring freshness and quality.

The cannabis flower has quite a long shelf life, but after about a year, it starts to lose its smell. The THC (tetrahydrocannabinol) doesn’t degrade as quickly, but the subjective quality of it begins to deteriorate.




Terpenes are the aromatic compounds in cannabis, and a lack of them can be a good indicator of whether the marijuana has degraded because it’s something that happens over time if not stored properly. After about five years, the plant material may start to turn brown because the chlorophyll evaporates.

Of great interest to those in the cannabis business is how the medicinal components of marijuana change over time causing the product to change from the day of purchase.

THC, the buzzy, euphoric cannabinoid can degrade over time if the flower is thrown into anything but an air-tight container and left in the dark. It changes into something called CBN, or cannabinol, which has a different psychoactive profile altogether. 

How long it takes before t cannabis properties change is unknown, but experts say a matter of months. You would certainly expect to see changes over a year.

As for cannabis oils, they can expire over time and should not be consumed past the expiry date. Fats are a food product that can eventually go rancid; cannabis resin diluted into something like store-bought MCT (medium chain triglyceride) oil. 

Also worth mentioning is how unnecessary it is to keep dried marijuana in the fridge or freezer. Some people do it to contain the natural smell of the pot, but the trichomes—crystal-like glands on the flower and leaves that produce the cannabinoids and terpenes—on cannabis are very delicate. When you freeze marijuana, they can fall off rendering the plant less potent.

Health Canada wants citizens to be responsible, by keeping dried marijuana in a cool, dry place and out of the reach of children and pets. 

The government said the proposed plain packaging would include a packaging date of the product and expiry date, if applicable.

If legalization means we get to know what we’re getting regarding cannabis potency, then having the product change over time without some warning is unnecessary. It’s likely not dangerous to use the plant after the “best by” date—not like chicken or dairy—so maybe “freshest before” is more appropriate. 

May 1, 2018

by Alana Armstrong

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Alana seeks to see cannabis from the perspective of politicians, advocates, entrepreneurs, and consumers. She got her start with a byline in the arts and culture section and crossed over into cannabis after using it medicinally. Current projects include investigations into cannabis and wellness; entrepreneurs of the Green Rush; cannabis for athletes; and the evolution of cannabis laws and culture in Canada.


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