Medical Marijuana

How the THC content of cannabis has changed over 50 years

Cannabis has been used medicinally for thousands of years. In the documents, there are references to the fact that it was used by the Scythians, Chinese, Japanese, and Persians. These ancients knew that the plant would give them a unique experience, but they had no idea about THC and, of course, how much of this substance is in their hashish.  

How the THC content of cannabis has changed over 50 years

Pharmacological experiments with individual cannabinoids were first carried out in the 1940s and 1950s. CBN became the first isolated cannabinoid: it was synthesized in 1940. As for THC, it was isolated from cannabis in 1942, and only in 1964 the Israeli professor Rafael Meshulam, together with his colleagues, was able to synthesize it. Thus, determine the percentage of THC in cannabis before the 1960s. it was simply impossible.

The golden age of cannabis: how strong was it?

In the 1960s and 70s. hippies smoked marijuana and listened to the iconic The Doors, Led Zeppelin, and Jimi Hendrix. At that time, the buds were not as powerful as they are now. One of the main reasons for this was their poor quality. Now that cannabis has been legalized in some countries, breeders can experiment with varieties, and the industry benefits from competition.  

In the 1970s. an ounce of cannabis (about 28 g) could be gotten for $ 20. However, half the weight was in seeds and stems. Since the plant was banned, most of it came to the United States from Colombia and other countries. Because demand exceeded supply, quality suffered greatly.

THC Content Testing

Since 1972, the state has begun testing the percentage of THC in seized cannabis samples. Their size and content varied greatly, so it is extremely difficult to determine the average value of one of the main cannabinoids. Cannabis usually contained no more than 3-4% THC. Moreover, in the 1970s. scientists analyzed no more than 18 samples per year, and now this number has increased to about 1000 per year.  

It should also be borne in mind that cannabis loses power over time. In many cases, samples were analyzed several months after harvest and were often improperly stored. Because of this, part of the TGC managed to transform into KBN. In this case, the real percentage of THC was definitely higher than the one that got into the statistics for the 1970s.

THC Content Testing

Another problem was that the tests were done using gas chromatography, which is not very suitable for evaluating cannabis. The fact is that before analysis, the samples were heated, which changed their chemical profile: the THC molecule was cleaved, and the data turned out to be incorrect. The testing now uses the liquid chromatography method, which gives more accurate results.   However, the fact that cannabis was not as powerful as it is now, and that sensimilia ( The seedless female flower of the cannabis plant)was almost impossible to find, is indisputable.


According to statistics, in the 1980s. the power of cannabis has dropped a lot, but is it true that it has gotten even weaker? Probably not, since at that time the bulk of the samples for testing were cannabis grown domestically, rather than illegally imported. In addition, the age of the harvested buds ranged from a few weeks to several years.

Moreover, the testing did not take into account the loss of THC due to improper storage.   The inadequate analysis makes it difficult to judge how powerful cannabis was in the 1980s.   In the 1980s. imported cannabis has decreased due to the growing popularity of hydroponics. The “home” buds were most likely more powerful than stated in the statistics, but now it will not be possible to get more accurate data.  

A study published in the journal Biological Psychiatry in April 2016 looked at how the potency of cannabis changed between 1995 and 2014. In total, almost 39,000 samples were analyzed. Scientists found that on average, cannabis in 1995 contained 4%  THC. Again, this data is difficult to take as an indisputable truth, but it can be assumed with some certainty that the effects of the buds were quite weak.  

In 1996, when California became the first state to legalize cannabis for medical use, the situation improved. From that time on, the bumps gradually became more and more powerful.

2000s – Today

According to the study, in the early 2000s. sensimilia among the tested cannabis has increased significantly. By 2014, the average THC content had increased to 12%. Also, the percentage of CBD was greatly reduced. In 2001, it was 0.28%, but by 2014 this value had dropped to 0.15%, which changed the ratio of THC to CBD: from 14: 1 to 80: 1. This significantly influenced the results of the analysis of the potency of cannabis. Due to the lower CBD content in the buds, THC was felt more strongly.

sensimilia among the tested cannabis has increased significantly

Nowadays, cannabis with THC above 20% is not as surprising as it used to be. You can even find killer varieties with more than 30% THC. However, the official data from federal researchers are somewhat different: they consider varieties with THC above 15% extremely rare, but most likely, they are testing the wrong samples.   Jonathan Page of the University of British Columbia in Canada says he is oblivious to varieties with THC above 28%. In his opinion, these indicators are either wrong, or breeders manipulate the composition of the cannabinoids in the samples to make the variety appear more potent.

Can it be argued that modern cannabis is more powerful?

The answer to this question is easy yes, but this answer may not be entirely correct. It should be remembered that in the 1960s and 70s. cannabis was banned in the United States and virtually every other country, making it difficult to obtain. The product that reached the consumer consisted mainly of stems and leaves, and there were very few buds and therefore THC.

Source: Potency Monitoring Program, Quarterly Report #146

Modern cannabis is easier to get, and usually, these are full-fledged buds, since there is no longer any demand for less.   It’s hard to believe that cannabis has suddenly magically become more powerful. It has been growing on the planet for tens of thousands of years, and its classic varieties from the Hindu Kush mountains are still very popular.

Of course, breeders are keen to develop cannabis with the highest percentages of THC and have already managed to produce buds with extremely potent effects. However, even this does not fully explain the sudden surge in power in recent years – it is doubtful that crossing existing varieties can produce such a result.   However, in 2017, High Times magazine spoke about the incredible Godfather OG, which contained a huge amount of THC  – 34%. And just 20 years ago, cannabis contained an average of about 4% THC. One way or another, even if the composition of the cannabinoids is manipulated, now many more consumers can enjoy buds with vibrant and pleasing effects.


Cannabis Sativa, Cannabis Indica, and Cannabis Ruderalis: Thank you for being the “Gateway drug” to perpetual inspiration, compassion, benevolence, and medicinal miracles: Cannabis grower, photographer with a long experience in cannabis cultivation. His articles are journalistic reports of places where cannabis is already legally cultivated and owned. They are intended to give an impression of the wide range of cannabis cultivation. These reports are intended to help identify the truth about cannabis and reduce prejudice.

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