Kratom naturally produces nitrogen-based chemicals called alkaloids that can have pronounced physiological actions on humans. The kratom plant has over 40 such naturally occurring bio-active alkaloids, of which perhaps the most well-known is mitragynine. Traditionally, day laborers in Southeast Asian countries chewed on kratom leaves to help with pain and energy. Additionally, kratom was used as a local anesthetic and also used to help with coughs and with intestinal issues like diarrhea. According to a 2020 survey of nearly 3,000 kratom users by John Hopkins Medicine, these days, a large portion of kratom users are using kratom to self-treat pain, while others use it for emotional or mental conditions.
Mitragynine can make up the majority of the total alkaloid content in kratom. Researchers study it for its potential analgesic (pain relief) effects and for its potential antitussive, antidiarrheal, adrenergic, and antimalarial effects. While 7-hydroxymitragynine is in tiny amounts in the natural plant it garners much research for its potentially powerful analgesic properties. Two other major alkaloids are speciogynine and paynantheine. They are studied as muscle relaxers.
Other alkaloids in kratom include: mitraphylline, ajmalicine, and isorhynchophylline. They are researched for their potential as immunostimulants and cerebrocirculants.