Herbal medicines containing myrcene have a long history of being used as a sleep aid in folk medicine. However, it’s not clear that any controlled studies have pinpointed myrcene as having a causal role in driving sleep in humans; we are not aware of any well-controlled human clinical trials that clearly demonstrate a sedative effect of myrcene.
A limited number of rodent studies have suggested that myrcene, given at high doses, may have muscle relaxant effects. The same study also showed that myrcene can increase the amount of time mice spent asleep, but only when given in combination with narcotics with strong sedative effects. However, animal studies often do not translate to humans, so more research is needed before we will have a clear indication of whether myrcene can produce sedative effects, especially at the levels it is commonly found in commercial cannabis products.