What is the difference between cannabis, marijuana and hemp?

Cannabis vs marijuana vs hemp comes down to one plant and two kinds of crop: cannabis is the plant, Cannabis sativa, while marijuana and hemp are types of it bred for different purposes. Marijuana is bred for THC-rich flowers that cause a high. Hemp is bred for fibre, seed and CBD and must stay under a legal THC limit: 0.2% for licensed seed in the UK and 0.3% in the EU.

What is the difference between cannabis, marijuana and hemp?

The three words are often used as if they meant the same thing. They do not.

• Cannabis is the botanical name. Cannabis sativa is one species in the Cannabaceae family, the same family as hops (McPartland, 2018).
• Marijuana (also "weed") is a common name for the dried flowers of cannabis bred for high THC. It is not a botanical or a UK legal term; UK law speaks of "cannabis".
• Hemp is cannabis bred for low THC and grown for its stalks, seeds and flowers. Lawmakers define it by a THC limit.

For each term in more depth, see what is cannabis? and what is hemp?

Are hemp and marijuana the same plant?

They are the same species, but not the same crop. Breeders have pushed them in opposite directions. In drug-type cannabis, the enzyme THCA synthase makes THCA, the acid form of THC. In fibre-type hemp, a sister enzyme, CBDA synthase, makes CBDA, the acid form of CBD, and CBDA is hemp's dominant cannabinoid (Taura et al., 2007). A breeding study found that a single gene locus largely decides whether a plant makes mainly THC or mainly CBD (de Meijer et al., 2003).

The differences go beyond that gene. Using 14,031 genetic markers in 81 marijuana and 43 hemp samples, researchers found that the two "are significantly differentiated at a genome-wide level". They also found that marijuana strain names "often do not reflect a meaningful genetic identity" (Sawler et al., 2015).

How much THC is in marijuana compared with hemp?

A lot more. In 38,681 cannabis samples seized by the US Drug Enforcement Administration, average THC rose from about 4% in 1995 to about 12% in 2014 (ElSohly et al., 2016). Hemp grown under a UK licence must come from approved seed with no more than 0.2% THC (Home Office, 2025), and EU rules set the limit at 0.3% (European Commission).

The THC content of a plant or product has to be measured; it cannot be judged by looks or smell. See how cannabis and hemp are tested for THC. For the compounds themselves, read what is THC? and CBD vs THC.

Is hemp legal in the UK, and is marijuana?

The Misuse of Drugs Act 1971 lists "Cannabis and cannabis resin" as Class B drugs (Schedule 2, Part II). Hemp is the same plant, so growing it needs a Home Office licence. The licence covers approved low-THC seed and "does not allow for use of 'green' material- i.e. the leaves and flowers as these are controlled parts of the plant" (Home Office, 2025).

CBD has its own position in UK law. The Home Office states that "Pure CBD, as an isolated substance, is not controlled under the MDA 1971", but that CBD products often contain traces of controlled cannabinoids such as THC (Home Office, 2024). For how this applies to CBD products, read is CBD legal in the UK?

What is hemp used for, and what is marijuana used for?

Hemp is a farm crop. Its stalk gives fibre for textiles, rope, paper and insulation, its woody core goes into hempcrete, its seeds go into food, feed and oil, and its flowers are the raw material for CBD extracts (European Commission). Read more in the uses of hemp.

Marijuana is grown for its THC-rich flowers, which are used as an intoxicant and, in some countries, in regulated medical programmes. In the UK it remains a Class B drug.

Where does CBD oil fit in?

CBD oil is made from hemp flowers, not from hemp seeds, and it is different from hemp seed oil. Seeds carry only traces of cannabinoids: analysis of ten hemp seed oils found THC, CBD and about 30 other cannabinoids at trace levels (Citti et al., 2019). Our guide to hemp oil vs CBD oil explains how to tell them apart.