Yes, you can use kava for sleep. Kava is known for providing a sense of tranquillity and relaxation, although a kava drink provides several other benefits such as treating insomnia and assisting in providing a more restful sleep.
Kavalactones are a pharmacologically active ingredient which is found in kava, and moderate to high doses of kavalactones is linked to increased drowsiness and sedation. It is important to consume the correct amount of kava drink.