Kratom is sorted into types primarily by vein color (red, green, white, and gold) and secondarily by regional names like Bali, Maeng Da, or Borneo. The vein color is the more meaningful distinction. It reflects differences in leaf maturity and post-harvest processing that change the plant’s chemical makeup and, in turn, how people experience its effects. Regional names are largely a marketing layer on top of the color system.
How Vein Color Creates Different Types
The three core kratom types are red, white, and green vein. These names originally referred to the color of the central vein running through the leaf, but in practice, the differences between commercial products come down to how the leaves are dried and processed after harvest. Red vein kratom undergoes longer drying times or fermentation, which shifts its alkaloid balance toward compounds associated with relaxation. White vein kratom is typically dried more quickly, preserving a profile that leans stimulating. Some producers also add ground kratom stems to white strains, since the stems are naturally richer in stimulating alkaloids. Green vein kratom falls between the two, with a processing method that produces a more balanced mix of both profiles.
Mature leaves are used for most kratom sold in the U.S. These mature leaves contain higher concentrations of several secondary alkaloids compared to younger leaves, though the primary active compound, mitragynine, is present in roughly equal amounts regardless of leaf age.
White Vein: The Stimulating End
White vein kratom consistently ranks as the most stimulating type. In a study published in the International Journal of Environmental Research and Public Health that measured user-reported effects across strains, white vein scored highest on measures of energy, stimulation, concentration, and the ability to stay awake. On a 100-point scale, white strains scored about 69 for concentration and 67 for energy, significantly outpacing red strains (around 50 and 53, respectively). People who use kratom for focus or productivity tend to gravitate toward white vein varieties.
Red Vein: The Relaxing End
Red vein kratom sits at the opposite end of the spectrum. It scored lowest on stimulation and energy in the same study and highest on measures associated with relaxation and sleepiness. The longer drying or fermentation process it undergoes is thought to enhance alkaloids that produce calming effects while reducing the stimulating ones. Red Bali is one of the most widely available red strains and is often recommended as a starting point for people new to kratom because of its relatively predictable, mellow profile.
Green Vein: The Middle Ground
Green vein kratom occupies the space between white and red. It scored significantly higher than red strains on energy and concentration but lower than white strains on stimulation. Users rated green strains around 61 for concentration and 64 for energy. This balanced profile makes green vein the most versatile type, and it’s a common choice for people who want moderate effects in both directions rather than a strong push toward either stimulation or sedation.
Gold and Yellow Kratom
Gold kratom (also called yellow kratom) is not a natural vein color. No kratom tree produces gold-colored leaves. These products are made one of two ways: blending red, green, and white vein kratom in specific ratios, or taking white or green vein leaves and drying them for an extended period of 15 to 20 days in sunlight. The prolonged drying turns the leaves from green to a yellowish gold and alters the alkaloid composition. Some producers use both methods, blending first and then fermenting the result. Most sources treat gold and yellow as interchangeable names for the same processing approach, though individual vendors may define them differently.
Regional Strain Names
Beyond vein color, kratom is marketed under regional names that refer to where the leaves were supposedly grown. The most common are Bali, Maeng Da, and Borneo, but you’ll also see Thai, Indo, Malaysian, and others. Each regional name comes in red, green, and white varieties, creating a matrix of options. Red Borneo, Green Maeng Da, White Bali, and so on.
Maeng Da is generally marketed as a more potent strain across all three colors. Green Maeng Da is positioned as a balanced option combining energy with a sense of well-being, while White Maeng Da is sold as having long-lasting stimulating properties. Bali strains are among the most popular and widely available. Red Bali is known for its calming profile, while Green Bali is marketed as a blend of relaxation and energy. Borneo strains follow similar color-based patterns, with White Borneo frequently described as providing clean, focused energy.
It’s worth knowing that these regional names are not tightly regulated. There is no certification system verifying that “Bali” kratom actually came from Bali. The vein color and processing method are more reliable indicators of what you’re getting than the geographic label.
Dose Matters More Than You Think
Regardless of strain or color, dose is a major factor in how kratom feels. At low doses (1 to 5 grams), kratom tends to produce stimulant effects across all types. At higher doses (5 to 15 grams), the effects shift toward sedation. Doses above 15 grams can produce effects that resemble opioid intoxication. This means a large dose of white vein kratom may feel more sedating than a small dose of red vein, even though their reputations suggest the opposite. The strain sets the baseline, but the amount you take determines where on the spectrum you land.
How Kratom Is Consumed
Dried leaf powder is the most common form. People take it as capsules, brew it into tea, or use the “toss and wash” method, which involves placing the powder directly in the mouth and swallowing it with a drink. In a pharmacokinetic study of kratom tea given to healthy adults, the primary active alkaloids were rapidly absorbed and detectable in the bloodstream, with mitragynine reaching peak blood levels within about an hour. Other alkaloids took longer, anywhere from 2 to 4.5 hours, which may explain why kratom’s effects can feel like they shift character over time as different compounds peak at different rates.
What Kratom Does in the Body
Kratom contains more than 40 structurally related alkaloids, but two do most of the heavy lifting. Mitragynine, the most abundant, and 7-hydroxymitragynine, which is present in much smaller amounts but is considerably more potent, both act as partial activators of the same brain receptors targeted by opioid drugs. Mitragynine also interacts with serotonin, dopamine, and norepinephrine systems, which helps explain why kratom’s effects span such a wide range, from stimulation to sedation to mood changes.
A third alkaloid called speciofoline has been identified at varying levels across commercial kratom products, enough to define two distinct chemical profiles among the 53 products tested in one analysis. Speciofoline does not bind to opioid receptors at all, which means its presence or absence could meaningfully change how a particular product feels, even within the same labeled strain.
Drug Interaction Risks
Kratom’s alkaloids are potent inhibitors of liver enzymes responsible for breaking down many common medications. Mitragynine strongly inhibits one enzyme pathway (CYP2D6) and acts as a time-dependent inhibitor of another (CYP3A), meaning its blocking effect actually gets stronger with continued exposure rather than wearing off.
The practical implications are significant. Even a low 2-gram dose of kratom was predicted to increase blood levels of certain CYP3A-processed medications by roughly 5.7-fold. For specific drugs, the predicted increases were striking: the anti-anxiety medication buspirone could see blood levels rise more than 14-fold, the immunosuppressant cyclosporine roughly 4.5-fold, and the sleep medication triazolam nearly 4-fold. Antipsychotics, blood pressure medications, and certain opioid painkillers are also affected. These interactions can potentially turn a normal dose of a prescription medication into a dangerous one.
Safety and Legal Status
The FDA has warned consumers against using kratom, citing risks including liver toxicity, seizures, and the potential for developing a substance use disorder. Deaths have been associated with kratom, though in most confirmed cases, other drugs were also involved, making kratom’s exact role unclear. Cases of physical dependence and withdrawal are well documented, with users reporting tolerance (needing more to get the same effect), cravings, and withdrawal symptoms when stopping. Newborns exposed to kratom before birth have experienced withdrawal signs including jitteriness, irritability, and muscle stiffness.
Kratom is not legally marketed in the U.S. as a drug, dietary supplement, or food additive. The FDA considers kratom-containing supplements to be adulterated under federal law. Despite this, kratom remains widely available for purchase in many states, though individual states and municipalities may have their own bans or restrictions. In September 2024, the FDA awarded a grant for a human abuse potential study on kratom, a step that could eventually shape future regulatory decisions.