According to the search engine on GNC's website, the nutrition store does not sell kava as of April 2014. Kava is available for purchase at Walmart and a variety of online stores.
According to Kava product description on Walmart's website, Kava may help to soothe nerves and relax muscles. Athough Kava is a natural supplement, it is not without risk. The FDA has reported that Kava has the potential to cause liver injury to those who take it. Potential signs of liver problems include jaundice or brown urine. Kava may also cause other side effects, including nausea, vomiting, tiredness, weakness, abdominal pain, drowsiness and loss of appetite.