CBD vs THC vs CBG vs CBN: A Plain-English Cannabinoid Guide

The cannabis plant produces more than a hundred compounds called cannabinoids, plus a host of aromatic terpenes. Most conversations only mention two of them — THC and CBD — but two "minor" cannabinoids, CBG and CBN, come up often enough that it is worth understanding all four. This guide explains each in plain English, how they work together, and how New Zealand law draws the line between a legal "CBD product" and a controlled drug.

Information and education, not medical advice. In New Zealand, cannabis-based products are prescription medicines; recreational cannabis is illegal. Always consult a registered doctor before using any cannabinoid product. 18+.

The four cannabinoids at a glance

Cannabinoid	Intoxicating?	Best known for	Notes
THC (tetrahydrocannabinol)	Yes	The "high"	Pain, appetite, nausea; can cause anxiety/paranoia at higher doses
CBD (cannabidiol)	No	Non-intoxicating relief	Studied for anxiety, seizures, inflammation; does not get you high
CBG (cannabigerol)	No (or minimal)	The "mother cannabinoid"	The chemical precursor the others are made from; early-stage research
CBN (cannabinol)	Very mild	Mildly sedating	Forms as THC ages/degrades; often discussed for sleep

THC — the psychoactive one

THC is the cannabinoid responsible for the intoxicating "high." It binds strongly to receptors in the brain and is behind cannabis's classic effects: euphoria, altered perception, increased appetite, and relief of pain and nausea. The same activity also drives its downsides — at higher doses THC can trigger anxiety, paranoia, a racing heart and impaired coordination and short-term memory.

In a medical context, THC is used (often alongside CBD) for chronic pain, nausea, appetite and muscle spasticity. Because it is intoxicating and impairing, it is the cannabinoid most relevant to driving and workplace-safety rules.

CBD — non-intoxicating

CBD is the cannabinoid that has driven most of the mainstream interest. Crucially, CBD does not get you high — it is non-intoxicating. It interacts with the body's systems more indirectly than THC, and researchers have studied it for anxiety, inflammation, and certain severe childhood epilepsies (the basis of the Medsafe-approved medicine Epidyolex).

CBD's non-intoxicating nature is also why NZ law treats qualifying CBD products differently from other cannabis medicines (more on that below).

CBG — the "mother cannabinoid"

CBG is often called the "mother of all cannabinoids." That is because its acidic form, CBGA, is the chemical precursor that the plant converts into THC, CBD and other cannabinoids as it matures. By harvest time most of the CBG has already been transformed, so mature plants usually contain only small amounts — which is part of why it is considered "minor."

CBG is non-intoxicating (or close to it). Research into it is still early-stage and largely preclinical, so claims about it should be treated cautiously rather than as established fact.

CBN — mildly sedating

CBN forms mainly as THC ages and degrades — older, oxidised cannabis tends to be higher in CBN. It is only very mildly psychoactive. CBN is most often discussed in the context of sleep and sedation, frequently combined with THC in sleep-oriented products. The evidence base specifically for CBN is thin, however, and much of its reputation may come from its association with aged, sedating cannabis rather than from CBN itself. (See our companion guide on cannabis and sleep for the detail.)

The entourage effect

The entourage effect is the idea that cannabis compounds work better together than in isolation — that THC, CBD, the minor cannabinoids and the terpenes interact to shape the overall effect. For example, CBD is often said to "take the edge off" THC's anxiety-provoking potential.

It is a plausible and widely cited concept, and it explains why full-spectrum extracts (which keep the plant's natural mix) are popular. But it is worth being honest: the entourage effect is not fully proven, and the science is still developing. Treat it as a useful working idea, not a settled law.

Terpenes, briefly

Terpenes are the aromatic oils that give cannabis (and many other plants) their smell — citrus, pine, pepper, lavender. They are not unique to cannabis; the same molecules appear in hops, herbs and fruit. Beyond aroma, terpenes are thought to contribute to the entourage effect and may modulate how a given chemovar (chemical variety) actually feels. This is increasingly seen as more useful than the old "indica vs sativa" labels, which are poor predictors of effect.

How the endocannabinoid system works (high level)

Cannabinoids affect us because the human body has its own endocannabinoid system (ECS) — a signalling network involved in regulating mood, appetite, sleep, pain and immune response. The ECS has three broad parts:

• Receptors — chiefly CB1 (concentrated in the brain and nervous system) and CB2 (more in immune tissue).
• Endocannabinoids — cannabinoid-like molecules our own bodies make.
• Enzymes — which build and break down those molecules.

THC produces its high largely by binding directly to CB1 receptors. CBD works more indirectly, influencing the system without the same direct CB1 activation — which is why it is non-intoxicating. In simple terms, plant cannabinoids interact with a system we already have, which is why they have such wide-ranging effects.

How NZ law defines a "CBD product" vs a controlled drug

This is where New Zealand is specific, and where overseas information is often wrong. Under NZ rules, a product only counts as a legal "CBD product" — rather than a controlled drug — if:

• CBD makes up at least 98% of the product's cannabinoids, and
• the "specified substances" (including THC and other controlled cannabinoids) make up no more than 2% of the total cannabinoid content (Ministry of Health, CBD products definition, accessed 2026-06-15).

If a product exceeds that 2% threshold, it is treated as a controlled drug, not a CBD product. Many products marketed overseas as "CBD" contain too much THC to qualify, and are controlled drugs in NZ.

Two further points often missed:

• A qualifying CBD product is still a prescription medicine. As of 2026, no low-dose CBD product had completed approval for over-the-counter pharmacist supply, so in practice CBD still needs a prescription in NZ.
• You cannot legally import CBD for yourself. It must be prescribed and dispensed through a pharmacy.

Frequently asked questions

Does CBD get you high? No. CBD is non-intoxicating. The "high" comes from THC.

Is CBD legal to buy over the counter in NZ? No. Even qualifying CBD products are prescription medicines, and as of 2026 there was no over-the-counter pharmacist-supply route in practice.

What makes something a "CBD product" legally in NZ? CBD must be at least 98% of the cannabinoids and specified substances (like THC) no more than 2%. Above that, it is a controlled drug.

Are CBG and CBN proven to do anything? They are real cannabinoids with plausible roles, but human research on them is limited. Treat strong marketing claims with caution.

Is the entourage effect real? It is a credible, widely cited idea that the compounds work better together, but it is not fully proven.

Sources

• Ministry of Health — Medicinal cannabis & CBD products definition; CBD products (controlled-drug threshold) (accessed 2026-06-15)
• Medsafe — approved cannabis medicines, including Epidyolex (CBD) (accessed 2026-06-15)
• Healthify NZ — Cannabis-based products patient guide (updated Feb 2026)
• bpacnz — Medicinal cannabis: overview for health practitioners (updated Feb 2025)

Information and education, not medical advice. Always consult a registered doctor. 18+.