Kratom is marketed as an "all-natural" supplement that can help reduce pain, anxiety, and depression, among other ailments. For some individuals who are wary of typical pharmaceutical medicines — as McKibban reportedly was — kratom can be an attractive alternative.

Chimaev ripped through the competition in his first few UFC bouts, immediately making himself into a man many believed was destined for UFC gold. Chimaev has had to battle through injuries, illnesses and travel issues to finally get his crack at a title and now looks to make good when he faces du Plessis in Chicago.