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What Happens To Old Marijuana?

How Long Does Weed Stay Fresh For?

When stored properly, dried cannabis keeps for 6 months to 1 year. Over time however, it begins to lose its aroma and potency. According to some older research, weed loses roughly 16 percent of its THC after 1 year, and it just keeps dropping from there:

  • 26 percent THC lost after 2 years
  • 34 percent THC lost after 3 years
  • 41 percent THC lost after 4 years

THC Turns Into CBN Over Time

cbn cannabinoidIn the simplest terms, a 1999 study shows that THC degrades into CBN over time, which means cannabis will typically become CBN-heavy the longer it ages. The study also reveals why CBN and THC cannabinoids share alternative mechanisms of action to CB1 and CB2 receptors.

Our current understanding of CBN as a major cannabinoid dates as far back as a 1999 study in which the United Nations Office on Drugs and Crime (UNODC) tested cannabis potency loss over time. According to the study, THC content in the tested cannabis sample dropped to half of its original potency after four years. Furthermore, as THC oxidized and dissipated, it began to convert to CBN. The study also found that the first two years of improper storage were when the most THC degradation occurred, drawing a clear connection between THC-CBN conversion and plant vulnerability.

How To Tell If It’s Old Weed

It’s mostly in the smell. Weed that’s past its prime will smell different or lose its aroma entirely. Some weed might even smell and taste harsh when it’s been sitting for too long. Its appearance can also give you a clue as to whether or not it’s old. Fresh marijuana shouldn’t crumble or feel spongy when you break it off. If it does, it’s old and either too dry or too moist.

Consuming it shouldn’t harm you, but be prepared for changes in texture and potency. The exception is weed that’s grown mold, which could potentially make you sick.