What’s in the stems?

We have all heard the rumors regarding marijuana stems. Some say they do not contain any cannabinoids, some say they do. We decided to investigate. We took three very different stem samples and ran an analysis using HPLC-UV.



Our first stem sample was from my personal stem jar. Many people save their stems for one reason or another. The stems in this jar had come from various high-quality strains, and they had been previously sifted over a screen to harvest the kief. A portion was parsed out of the jar and processed using the same procedures and methods as a typical cannabinoid profile. These stems had a Max THC of 1.2%. There was no CBD and 0.1% of CBN.

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The second stem sample came from flowers that had been pollinated. The sample was prepared in the same manner as the previous one, and the results were very similar. The Max THC was 1.1%, and there were no other cannabinoids found.


The third stem sample came from flowers that we had previously tested. The tested flowers had a Max THC of 18.3%, which is higher than average. We expected these stems to measure similarly to the previous two samples. We were surprised to see that the Max THC of these stems measured out to 9.2%, which is higher than many bud samples that we’ve tested.

sour diesel comparison stem and bud

We will be conducting tests on more samples to get a better understanding of what to expect in the stems, however these results show us that not all stems are created equal. Just like the variance we see in flower and concentrate samples, stems can have varying levels of potency. When trying to make some sense of these numbers, consider this: one gram of stems from the third sample has about 80 more mg’s of THC than one gram of stems from the first two samples. Think twice before throwing your stems away next time.

comparing stems

About The Author

Jon is a cannabis connoisseur. He has studied the history and science of cannabis for over 10 years, and brings a wealth of very applicable knowledge to MCR Labs. Favorite strain: The Illusive Mothership. A clone only Sativa from the Pacific North West. Favorite extract: actively searching for favorite.

  1. Old Hippie 11/21/2014, 1:05 am Reply

    Nice work! I’ll be referencing this in my upcoming book. Nugs and hugs!

    • Jonathan Wani 12/04/2014, 9:21 pm Reply

      Thanks Old Hippie, I would love a copy once it is published.

  2. Stephen 11/21/2014, 1:17 pm Reply

    Great analysis. I saw one a couple of weeks ago where a guy scraped resin from his bowl and tested it. I’d like to see one on AVB as well.

    • Karen 12/07/2014, 9:01 pm Reply

      Just came across this off of a FB Cannabis page! GREAT to know!
      Stephen, where might I find the analysis from that resin/bowl testing?
      Thanks in advance! <3

  3. Charlie 12/06/2014, 5:03 am Reply

    I’ve been wondering this very thing for awhile thanks for the info. It is similar to what I have thought. I would also like to see the results of concentrates made from stems and like Stephen’s suggestion AVB or “already been vaped,” and concentrates made from that as well. Great work either way. I’ve literally been studying cannabis and it’s effects on people since birth. My parents and family friends all used frequently. I also picked up the daily habit between 12-16 and I am 32 now. I have always suffered from extreme night terrors and daily use of marijuana is the only thing that lets me forget my dreams enough to get to sleep and then stay asleep. However I’ve never seen this listed as a medical use and that just seems like such a shame because if people knew it could help many more like me. I still live in an illegal state (Ohio) and have served prison time for possession of marijuana so finding employment is tough. If MCRlabs is hiring I have a wealth of information that could be useful. : )

  4. Owen Smith 12/07/2014, 7:24 pm Reply

    it’s not in the stems it’s on them

    • veronica 09/07/2016, 7:17 pm Reply

      They scraped that off as they stated. “The sample was prepared in the same manner as the previous one”

  5. Tsculy 12/02/2015, 4:35 pm Reply

    What was the methods for the extraction fo compounds you used? Cause sample prep can influence very much the levels of anything you want to measure! Also, did you made triplicates?? One measurement may not be enough.

    • Jonathan Wani 12/02/2015, 4:42 pm Reply

      Our method of extraction is a validated methanol extraction with multiple dilution schemes. All of the samples were run in duplicate and the values averaged for the final results.

  6. Andy 12/08/2015, 4:18 pm Reply

    So from what I understand is that the third sample came straight off the bud therefore are you measuring stems or maybe just the amounts of keef on them? Or both I am assuming since you sifted the first sample and made it clear then it may just be keef on the stems correct?

  7. Miranda Nick 01/04/2017, 4:43 am Reply

    Hello. Were they dry stems?

  8. Miranda Nick 01/04/2017, 4:44 am Reply

    I’m making tea from stems and I want to take this test on the tea. What is the test supply called?

  9. Miranda Nick 01/04/2017, 4:45 am Reply

    Also, my main question is what is the difference of thc on dry and fresh stems?

  10. JOHANNA DAVIS 01/10/2017, 2:55 pm Reply

    I am starting an medible company and only use the stems and leaves of the plant for our product we make Rubs Edibles and tinksters! Our patients are benefiting tremendously from our product… I haven’t had our product tested yet and at this point can only give our product away, witch sucks but we are finding out so much info on our product just from people’s accounts and how it helps them feel better how much pain it relieves, nausea gone, insomnia gone, anxiety relief! We are proud of our product… I say you decently need to do some more testing! It has been mention to us that the process that we are doing with the plant maybe releasing unseen potential in the plant that isn’t seen threw conventional testing we have been giving me advice to have the finished product tested as that may have a different result as a plant its self. That is our next step in our business is the testing.

  11. Mat 02/04/2017, 4:30 pm Reply

    I would be curious, and I’m sorry if I missed it in the comments, but what the the first two samples test at? Like the flower that they came from? I’m just wondering if there’s some sort of consistent ratio between the flower itself and what cannabinoid content is in the stems. I’m sure it has tons of other variables as well. Very interesting stuff. I’m also one of the people who always wanted to get the resin out of their pipe tested, just to see what it is. I’m assuming lots of CBN and maybe some other stuff we’re not quite familiar with yet.

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