How a single plant hijacks your body's internal regulatory system

Nature · Published 3 October 2026 Swipe more like this →

In short: Your body possesses a built-in endocannabinoid system designed to regulate mood, memory, and appetite. When you consume cannabis, external cannabinoids like THC arrive to over-activate these natural receptors, creating a profound physiological shift. But how exactly does the method of consumption change the way these chemicals interact with your brain?

The interaction begins with the endocannabinoid system, which uses natural cannabinoids to maintain balance. When substances from the Cannabis sativa plant are introduced, they mimic or overwhelm these signals. The most prominent driver of the 'high' is delta-9-tetrahydrocannabinol (THC), a psychoactive cannabinoid that binds to receptors in the brain and various organs. In contrast, cannabidiol (CBD) is non-psychoactive and is studied for its potential to manage inflammation, epilepsy, and neuropathic pain.

The speed and intensity of these effects depend heavily on the route of administration. When inhaled, THC enters the bloodstream rapidly through the lungs, reaching peak levels in just 6 to 10 minutes. This method has a bioavailability of 10% to 35%. Conversely, when ingested via food or drink, the body absorbs the substance much more slowly—typically taking 30 minutes to an hour—and with a much lower bioavailability of only 4% to 12%. Once absorbed, THC is processed by the liver and is highly lipid-soluble, meaning it is quickly taken up by fat tissue.

While many experience euphoria or relaxation, the effects are highly individual and influenced by genetics, age, sex, and frequency of use. High doses can lead to hallucinations or psychosis, while long-term use is linked to various risks. These include potential changes to brain development in adolescents, increased risk of stroke or heart disease from smoking, and cannabis hyperemesis syndrome, which causes severe vomiting. Researchers continue to study these long-term impacts to better understand the full scope of the plant's influence on human biology.

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