Kratom extract is a refined form of kratom made by extracting the alkaloids mitragynine and 7-hydroxymitragynine from kratom leaves or powder. Making kratom extract is simple: leaves or powder are boiled to create a solution, which is then strained to remove the solid particles. Next, the remaining solution is simmered down, which causes the water to evaporate. Once the solution is a paste, it dries, and then the resulting substance is ground down into a powder.
The difference between kratom extract and regular kratom powder is that kratom extract is a refined concentration of alkaloids and other active ingredients, while the powder is simply dried leaves that have been ground into powder. The liquid form of kratom extract should be unadulterated, merely consisting of the pure extract combined with water. However, some manufacturers take the opportunity to combine liquid kratom extract with other things to create a cocktail of sorts, or liquid kratom shots.