When used in small doses, Kratom has stimulant effects, boosting mood and energy. Larger doses often have more sedative-narcotic effects. However, you will need to adjust your dose depending on the type of Kratom you consume.
For example, Thai Kratom is often far more powerful than Indonesian and Malaysian Kratom. The reason for that is that the chemical compount of kratom can depend on a number of things. Think of the variety of the plant, its age, its environment, the time of harvest, etc. Similarly, kratom resins usually hold 3x more of the active ingredient (mitragynine) than drief leaves or powdered kratom products.
So find yourself a trustworthy, reputable supplier and follow their instructions. Starting with a smaller dose that you can build up over time is not only easier on your body but you will experience and appreciate the full range of effects that Kratom has to offer.