In Thailand itself the kratom leaf has been illegal since the 1940s, although given that the Mitragyna speciosa grows abundantly in the wild the ban has had minimal effect on overall usage rates. A recent study released by the Office of Narcotics Control Board has called for the decriminalization of the plant, as research into its initial prohibition has uncovered that it was largely for economic, rather than social or health reasons.There is no definitive guide to the characteristics of each strain, and like coffee beans even leaves harvested from the same region can vary greatly in their strength, effect, and overall quality. The real differences come from the chemical composition of the plant and how the processing by specific suppliers supplements, alters, or otherwise changes that initial composition. In general all kratom leaf products produce an energetic boost at low dosages, and a more sedative affect with higher consumption. The strength and effects are also largely dependent on the medium through which they're ingested. While many people are most comfortable steeping powdered extract for tea, there are also options to buy kratom resin, capsules, and various other forms.