Tolerance is said to occur when the effect of a drug decreases over the course of repeated administrations [1]. Today we’re going to address this in regards to kava. In 1991 researchers set out to answer whether kava caused tolerance. Mice received dosages from 50mg per kilogram of body weight up to 300mg per kilogram of body weight of kava extract. The experiment was odd in that it used what they considered an “aqueous” extraction alongside solvent extracts, but this extract was said to be “free of pyrones” or completely lacking kavalactones. I personally have to question this conclusion about this “water extract”, and as such I will be omitting it from our facts today. I believe there likely were kavalactones in the water extract, albeit a very small amount, however the study failed to further test the resulting extracts. It was found that tolerance failed to develop in doses up to 300mg/kg of kava resin per day. This would be roughly equal to the intake of >18,000mg of kavalactones per day in an average human. Obviously dosages at the top range of this study we will likely never see in terms of average consumption in humans. This study concluded that kava resin did not readily produce physiological tolerance, nor was learned tolerance rapidly developed [2].
Okay, so there’s no physical tolerance observed for kava, but why does my kava experience change over time?
This is a question we see pretty regularly, and to date, there is yet to be a very satisfying answer. Here we’ll have to use our personal experiences to try to answer. I’ve been drinking kava at the dose of 40g per day for the last 16 years. I never add more or use less. 40 grams prepared traditionally day after day. Over the years my kava experience has waxed and waned, however I’ve never found what I would consider a tolerance. I define tolerance through my experience with opioid drugs. At the end of an active addiction to opioids your dosage rate will be many many times your original starting dose due to drug tolerance. If this were the case for kava I would be consuming literal pounds of kava powder per day to keep the effects where I want them to be, and I just don’t see this.
Where there may be some type of tolerance at play is psychologically. We may become accustomed to the effects over time and not perceive them as strongly as we once did, even though the effects remain the same. Another area which may affect this is the combination with other substances. When other chemicals are consumed at the same time, the complex pharmacodynamics of each can cause differences in perceived effects. Another (remote) possibility is that you do gain a tolerance, but only to specific kavalactones. This study only used crude (full spectrum) kava extracts and not individual kavalactones.
Most likely the largest culprit of what is thought of as “tolerance” is simply variations in kava quality over time. Kava, as a natural product, has variations between plants, and as such will also have a variation of effects between bags. This is due to factors such as growing conditions, age of plant, and plant part. No clinical tolerance with kava has been observed.
[1] Siegel, Shepard. 2005. “Drug Tolerance, Drug Addiction, and Drug Anticipation.” Current Directions in Psychological Science 14 (6): 296–300.
(https://doi.org/10.1111/j.0963-7214.2005.00384.x)
[2] Duffield, P. H., and D. Jamieson. 1991. “Development of Tolerance to Kava in Mice.” Clinical and Experimental Pharmacology & Physiology 18 (8): 571–78.
(https://doi.org/10.1111/j.1440-1681.1991.tb01493.x)
Okay, so there’s no physical tolerance observed for kava, but why does my kava experience change over time?
This is a question we see pretty regularly, and to date, there is yet to be a very satisfying answer. Here we’ll have to use our personal experiences to try to answer. I’ve been drinking kava at the dose of 40g per day for the last 16 years. I never add more or use less. 40 grams prepared traditionally day after day. Over the years my kava experience has waxed and waned, however I’ve never found what I would consider a tolerance. I define tolerance through my experience with opioid drugs. At the end of an active addiction to opioids your dosage rate will be many many times your original starting dose due to drug tolerance. If this were the case for kava I would be consuming literal pounds of kava powder per day to keep the effects where I want them to be, and I just don’t see this.
Where there may be some type of tolerance at play is psychologically. We may become accustomed to the effects over time and not perceive them as strongly as we once did, even though the effects remain the same. Another area which may affect this is the combination with other substances. When other chemicals are consumed at the same time, the complex pharmacodynamics of each can cause differences in perceived effects. Another (remote) possibility is that you do gain a tolerance, but only to specific kavalactones. This study only used crude (full spectrum) kava extracts and not individual kavalactones.
Most likely the largest culprit of what is thought of as “tolerance” is simply variations in kava quality over time. Kava, as a natural product, has variations between plants, and as such will also have a variation of effects between bags. This is due to factors such as growing conditions, age of plant, and plant part. No clinical tolerance with kava has been observed.
[1] Siegel, Shepard. 2005. “Drug Tolerance, Drug Addiction, and Drug Anticipation.” Current Directions in Psychological Science 14 (6): 296–300.
(https://doi.org/10.1111/j.0963-7214.2005.00384.x)
[2] Duffield, P. H., and D. Jamieson. 1991. “Development of Tolerance to Kava in Mice.” Clinical and Experimental Pharmacology & Physiology 18 (8): 571–78.
(https://doi.org/10.1111/j.1440-1681.1991.tb01493.x)
