Cannabis Effects: How Cannabis Works in the Body

Cannabis works because the human body has its own cannabinoid system — the endocannabinoid system (ECS). Without this system, cannabis would have no effect. The ECS regulates mood, sleep, appetite, pain perception, and the immune system. This article explains how cannabis influences these processes, why THC causes a high and CBD does not, and why people react so differently to cannabis.

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The Endocannabinoid System: The Basis of Cannabis Effects

How THC works: Explaining the psychoactive effect

How CBD works: Without a high, but with effects

Why do people react so differently to cannabis?

Cannabis for different indications: What happens in the body?

Frequently asked questions about the effects of cannabis

The Endocannabinoid System: The Basis of Cannabis Effects

The endocannabinoid system was discovered in 1992 — ironically through the study of THC. It consists of three components:

Endocannabinoids: Endogenous cannabinoids — the most important are anandamide (named after the Sanskrit word for “inner joy”) and 2-AG (2-arachidonoylglycerol)
Cannabinoid receptors: CB1 receptors (mainly in the brain and nervous system) and CB2 receptors (mainly in the immune system and peripheral tissues)
Metabolic enzymes: FAAH and MAGL break down endocannabinoids after use — CBD inhibits this breakdown

The ECS functions as a retrograde neurotransmitter: signals flow “backward” — from the receiving cell to the sending cell. This makes it unique among neurotransmitter systems and explains why cannabis can influence so many different processes at the same time.

How THC works: Explaining the psychoactive effect

THC (Tetrahydrocannabinol) binds directly and with high affinity to CB1 receptors — especially in the prefrontal cortex (decisions, planning), in the limbic system (emotions, memory), in the basal ganglia (motor control), and in the brainstem (nausea, pain).

The typical THC effect sequence:

Onset (0-5 min with inhalation): THC reaches the blood through the lungs, then the brain. CB1 receptors are activated.
Peak (20-40 min after inhalation): Highest THC concentration in the blood. Euphoria, altered perception of time, increased creativity — or, at too high a dose, paranoia and anxiety.
Plateau (1-2h): Stable phase of effect. Relaxation, pain relief, altered sensory perception.
Comedown (2-4h after inhalation): THC levels drop. Fatigue, hunger (“munchies”), occasionally mild melancholy.

Duration of effects depends on the method of consumption — from immediate to 8 hours: Cannabis Duration of Effects.

How CBD works: Without a high, but with effects

CBD (cannabidiol) binds only weakly to CB1 or CB2 receptors. Instead, it works through several indirect pathways:

FAAH inhibition: CBD blocks the enzyme FAAH, which breaks down anandamide. More anandamide = longer-lasting endogenous “happiness”
5-HT1A agonism: CBD activates serotonin receptors — this explains the anxiolytic effect
TRPV1 activation: CBD directly influences pain receptors
THC modulation: CBD reduces the binding affinity of THC to CB1 receptors — it “buffers” the high

The result: CBD can have a calming, pain-relieving, and anxiety-reducing effect without impairing cognition or causing psychoactive effects. The complete Comparison: CBD vs. THC: Differences explained.

Why do people react so differently to cannabis?

The same amount of cannabis can cause completely different effects in two people. The reasons:

CB1 receptor density: Genetically determined. More CB1 receptors = stronger reaction to THC
CYP2C9 genotype: This liver enzyme breaks down THC. “Poor metabolizers” break down THC more slowly — more intense and longer-lasting effects
Tolerance: Regular use leads to CB1 receptor downregulation — fewer receptors = weaker effects
Body fat: THC is fat-soluble. More body fat = more storage capacity = longer detection time, but also a slower peak build-up
Setting and mindset: The “set and setting” effect is very pronounced with cannabis — fear of consumption can trigger paranoia even with small amounts
Strain and terpene profile: The terpenes of the plant significantly modulate the cannabinoid effects — the entourage effect

More about terpenes and their enhancing effects: Cannabis Terpenes — Myrcene, Limonene, Caryophyllene explained.

Cannabis for different indications: What happens in the body?

The ECS regulates many physiological processes — which explains why cannabis is therapeutically used for such a variety of conditions:

Pain: CB1 activation in the spinal cord inhibits pain transmission. CB2 activation reduces peripheral inflammation. Combination of THC and CBD works synergistically (entourage effect). More: Cannabis for Pain
Sleep: THC speeds up falling asleep but shortens REM sleep in long-term users. CBD regulates the sleep-wake rhythm indirectly through serotonin. More: Cannabis for Sleep Disorders
Anxiety: Low-dosed THC + CBD has anxiolytic effects via CB1 and 5-HT1A. High-dosed THC can paradoxically intensify anxiety. More: Cannabis for Anxiety Disorders
ADHD: THC increases dopamine levels in the prefrontal cortex — similar to stimulants, but less direct. More: Cannabis for ADHD

How cannabis influences medication levels via the CYP450 system: Cannabis Interactions: Which Medications to Avoid? — a practical guide for patients.

Anyone who wants to understand how cannabis works via the endocannabinoid system should also consider the method of consumption: Cannabis Vaporizers: The Best Devices for Medical Cannabis — inhalation vs. oral intake in a comparison of effects.

Especially relevant for expectant mothers: Cannabis during pregnancy: Risks and facts — how THC influences fetal brain development through the endocannabinoid system.

Who understands the endocannabinoid system also understands why withdrawal occurs: Cannabis withdrawal: Symptoms, duration and how to quit — desensitization of CB1 receptors and what this means for those affected.

Especially relevant for people with a pre-existing mental health condition: Cannabis and psychosis: Risks and facts — who has an increased risk and why the CBD content protects.

CB1 receptor desensitization is the basis of cannabis tolerance: Cannabis tolerance & T-break: How the reset works — what happens in the brain and how a T-break reverses it.

CB1, CB2, Anandamide, 2-AG, FAAH — all ECS terms at a glance: Cannabis Glossary: The most important terms explained simply — complete cannabis glossary with endocannabinoid system, cannabinoids, and consumption terminology.

Frequently asked questions about the effects of cannabis

Wie schnell wirkt Cannabis?: Bei Inhalation (Rauchen, Vaporizer) setzt die Wirkung innerhalb von 1-5 Minuten ein, der Peak liegt nach 20-40 Minuten. Bei oraler Einnahme (Öl, Edibles) dauert es 45-90 Minuten bis zum Onset, dafür hält die Wirkung länger an — bis zu 6-8 Stunden.
Warum macht THC high, CBD aber nicht?: THC bindet direkt und hochaffin an CB1-Rezeptoren im Gehirn, besonders im limbischen System und präfrontalen Kortex. Dieser Mechanismus erzeugt das “High”. CBD bindet kaum an CB1-Rezeptoren, wirkt stattdessen modulierend über andere Rezeptorsysteme — ohne psychoaktiven Effekt.
Was ist das Endocannabinoid-System?: Das Endocannabinoid-System (ECS) ist ein körpereigenes Signalsystem mit Rezeptoren (CB1, CB2), körpereigenen Cannabinoiden (Anandamid, 2-AG) und Abbauenzymen. Es reguliert Stimmung, Schlaf, Appetit, Schmerzwahrnehmung und Immunreaktionen. THC und CBD wirken, weil sie an dieses System andocken.
Warum reagieren manche Menschen stärker auf Cannabis?: Die CB1-Rezeptordichte ist genetisch bedingt. Zudem beeinflusst der CYP2C9-Genotyp, wie schnell die Leber THC abbaut. “Poor Metabolizer” erleben stärkere, längere Wirkungen. Toleranz (bei regelmäßigem Konsum), Körperfett und das psychologische Setting spielen ebenfalls eine Rolle.