Why it matters
In pharmacology, “alkaloid” is a structural category, not a functional one. The defining feature is the presence of one or more nitrogen atoms (usually in a ring), which gives the molecule basic properties — alkaloids tend to ionise predictably and bind to receptors that evolved to recognise endogenous amines like dopamine, serotonin, and noradrenaline. Caffeine, morphine, nicotine, quinine, and atropine are all alkaloids.
In practice
Kratom’s alkaloid family includes mitragynine, 7-hydroxymitragynine, paynantheine, speciogynine, speciociliatine, and corynantheidine, among others. Each binds slightly different receptor populations. Strain and harvest variation changes the ratio between them, which is why the same “10 grams” of two different leaf products can feel different. A Certificate of Analysis that reports only mitragynine and ignores the rest is giving an incomplete picture of the product.
Common confusion
“Alkaloid content” on a label is sometimes equated with “potency.” That conflation hides important nuance: a sample with high total alkaloids but low mitragynine, or skewed toward sedating alkaloids like speciogynine, will not feel like a high-mitragynine sample at the same total alkaloid percentage.
This glossary entry is editorial content reviewed against primary sources. It is not medical advice. See our Editorial Policy.