Why Does Indica Make You Sleepy?

All seasoned cannabis enthusiasts know that indica tends to make you sleepy, sometimes even causing "couch lock" - making it your best friend for any (Netflix) Marathon Sunday. But why is this the case?

Lets start out with a brief introduction of the strain. Indica plants can be identified visually because they grow short and wide relative to sativa. Side note: these make them ideal for indoor growing in confined spaces. They result in a very relaxing and strong body high that is helpful in treating general anxiety, body pain, and sleeping disorders.

Relieves body pain
Relaxes muscles
Relieves spasms, reduces seizures
Relieves headaches and migraines
Relieves anxiety or stress

But Why? What's going on at the chemical level?  

First - terpenes. Myrcene is a "terpene," or one hydrocarbon found in the essential oils of plants. It is one of the most common aromatic compounds in the cannabis plant, and has recently been discovered as one of the reasons why some cannabis strains have sedative and motor relaxant effects.

In a 2002 study, researchers found that mice who were treated with 200 mg/kg of myrcene slept an average of 2.6 times longer than untreated mice. Some evidence also suggests that myrcene may also boost the potency of THC by helping it cross the blood-brain barrier more easily.

The 2002 study found that limonene, the molecule responsible for the lemon aroma in some strains, may also cause sleepiness and motor relaxation. Linalool, a terpene with a lavender scent, also has been shown to produce sedative and anti-anxiety effects.

Second - CBN. CBN is another cannabinoid (such as THC and CBD) present in the plant. While CBN induces little to no psychoactive effects, its characterizing attribute is its sedative effect. According to Steep Hill Labs, 5mg of CBN is as effective as 10mg dose of diazepam, a mild pharmaceutical sedative. There is not a lot of CBN in dried flower - where THC contents can hit a high watermark of over 30%, CBN rarely exceeds 1% in dried flower - which is fine, because a little bit goes a long way. One indica strain with a particularly high level of CBN is Ace of Spades.

So if you find a strain that is high in THC, CBN and sleepy terpenes, prepare for the best night of sleep you've ever had.