Hemp is one of the oldest plants cultivated by humans. It is used in various industries, including cosmetics, textiles, construction, pulp and paper, food, and pharmaceuticals. With the development of new technologies, further applications for hemp fibers have been developed - they can be used as a substitute for glass or carbon fibers in bio-composites or used in the production of efficient batteries. The prevalence of hemp fiber products on the Polish market, including food products and dietary supplements, has significantly increased in recent years. Therefore, it should be remembered that some products, especially oils, may contain trace amounts of THC as a manufacturing impurity.

The availability of treatment with THC-containing preparations as an active substance has also increased. This was made possible by legislative changes introduced in 2017 (Journal of Laws of 2017, item 1458), allowing the use of non-fiber hemp and its extracts and tinctures as a pharmaceutical raw material for the preparation of prescription medicines.

Hemp plants belong to the Cannabis sativa L. species, among which three subspecies are distinguished:

• Cannabis sativa L. subsp. Sativa - fiber hemp
• Cannabis sativa L. subsp. Indica - Indian hemp
• Cannabis sativa subsp. Ruderalis J. - wild hemp/li>

Approximately 600 compounds found in cannabis have been isolated, of which the phytocannabinoids have attracted the most interest. This is a group of about 100 substances that act via cannabinoid receptors in the brain. The best-known compounds in this group include THC (Δ9-tetrahydrocannabinol) and CBD (cannabidiol).

Differences between fiber hemp and non-fiber hemp are related to the different content of pharmacologically active substances, including THC. Fiber hemp is recognized as varieties in which the sum of THC and tetrahydrocannabinolic acid (delta-9-THC-2-carboxylic acid, THCA) in the flowering or fruiting tops of the plants from which resin has not been removed does not exceed 0.2% THC. The cultivation of fiber hemp is allowed in Poland after obtaining the relevant permit and is subject to strict control. THC occurs in large amounts in the flowering and fruiting tops of non-fiber hemp plants, commonly known as marijuana.

There are increasing reports about the medical applications of THC. Scientific research is being conducted on the use of THC in treating the negative effects of chemotherapy (such as nausea, vomiting) or anorexia. Reports have emerged on the positive impact of THC on stimulating appetite in people with AIDS. In the case of treating multiple sclerosis and amyotrophic lateral sclerosis, a reduction in muscle scan cause a feeling of intoxication and impair the ability to drive vehicles, disrupt cognitive functions, working memory, attention, and motor coordination. It can also cause short-term periods of anxiety, panic, and psychosis.

It should be remembered that THC is a psychoactive substance from Group II-P as defined in the Regulation of the Minister of Health of August 17, 2018, on the list of psychotropic substances, narcotic drugs, and new psychoactive substances (Journal of Laws of 2018, item 1591, as amended), therefore, the detection of this substance in the body may have legal consequences.

The trace amounts of THC in industrial hemp can result in the accumulation of THC and its metabolites in the body when consuming large amounts of their preparations, dietary supplements, particularly those described as "full spectrum".

THC is metabolised by several enzymes. Of particular importance for the rate of metabolism is the CYP2C9 enzyme of the cytochrome P450 family. In about 10-20% of the Polish population, this enzyme exhibits decreased activity, which significantly affects the length of the effects of THC and the time it can be detected in the body. Therefore, when using hemp preparations, it is advisable to do so in a conscious manner to avoid unwanted legal problems.

• Act of July 29, 2005, on Counteracting Drug Addiction (Journal of Laws of 2023, item 172)
• Act of July 7, 2017, amending the Act on Counteracting Drug Addiction and the Act on Refunding Medicines, Special Nutritional Products, and Medical Devices (Journal of Laws of 2017, item 1458)
• Regulation of the Minister of Health of August 17, 2018, on the list of psychotropic substances, narcotic drugs, and new psychoactive substances (Journal of Laws of 2018, item 1591, as amended)
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