Where does the 0.3% THC limit in hemp come from?

In most countries, the distinction between hemp and cannabis revolves around a THC content of 0.3%. But where does that number come from?

The European THC limit for hemp was initially set at 0.5% in 1984, then reduced to 0.3% in 1987, based on a widely recognized study titled «A Practical and Natural Taxonomy of Cannabis,» conducted in 1976 by American plant taxonomists Ernest Small and Arthur Cronquist on behalf of the International Association for Plant Taxonomy (IAPT).

This study, based on the dry weight of the hemp flowers, arbitrarily established that the THC level of 0.3% is the threshold that distinguishes Cannabis sativa (non-medicinal cannabis—industrial hemp) from Cannabis indica (medicinal cannabis—«marijuana»). Since Europe is generally considered a pioneer in this area, the 0.3% standard was quickly adopted by Canada and other countries, and eventually by the United States when the U.S. Farm Bill of 2014, and then the one from 2018, have enabled U.S. producers to revitalize the industry in that country.

When hemp made a comeback in Europe at the end of the last century, a new generation of stakeholders focused on the hemp cultivation for its fibers. Meanwhile, Europe took a step backward in 1999—somewhat inexplicably—by further reducing the permitted THC content for hemp to 0.2%.

At that time, France was well positioned to draw on their expertise in hemp, having developed hemp varieties with low THC content throughout the 1980s and 1990s, which supplied the country’s paper and construction industries. There is every reason to believe that the lowering of the THC limit for industrial hemp from 0.5% to 0.3% and then to 0.2% may not have been initiated by French crop seed breeders, but that they certainly did not oppose it.

Committed to remaining in compliance with EU directives, and still in the shadow of the global war on drugs, other European growers were forced to comply with the 0.2% THC limit if they wanted to grow hemp. It was the only way to gain access to the EU grant programs designed to support the industry; subsidies were particularly popular in France, Europe’s leading producer of hemp fiber, where the government would occasionally ease the situation by providing additional national subsidies.

While the dietary supplements and hemp-based foods were beginning to spread throughout the world, the CBD quickly accounted for more than half revenue from the global hemp industry. Against this backdrop of rapid growth, the 0.2% THC limit imposed by the European Union has put European market players at a significant disadvantage.

In 2021, following the surge in many agricultural and industrial stakeholders, including the EIHA, the CAP decided to return to a THC level of 0.3% in hemp for the disbursement of this aid.

Among the many issues raised by the 0.3% threshold, one example is the very limited leeway available to the farmers subject to these regulations. Despite their best efforts, natural variations—such as environmental conditions—can transform a legal crop into a «high» crop that exceeds the 0.3% threshold without necessarily becoming more psychotropic. In such cases, the crop must be confiscated and/or destroyed at the farmer’s expense—and criminal charges may even be filed.

A European country, however, has full discretion to exceed this level in the plant. Italy has set it at 0.6%, Switzerland and the Czech Republic: 1%. The only restriction is that these plantations are no longer eligible for CAP subsidies. However, they remain fully compliant with national law, which established these rates.