Red vein kratom is the category of kratom that all red strains belong to. Each strain is harvested from majority red vein leaves, meaning the leaves that were harvested for the batch have a red stem and vein in color. The veins itself don’t influence the color of the powder for any given strain as the color of all leaves are green. The drying process and maturity of the leaves harvested can impact the color of the powder and some red strains may have a darker appearance. Red strains are typically the most popular type of kratom and are said to be the most calming.