“MIT kratom” refers to kratom products with high concentrations of mitragynine, the primary active alkaloid in the kratom plant. The term most commonly points to the brand MIT45, one of the best-known names in concentrated kratom extracts, but it also appears as a general label for mitragynine-enriched products sold as liquids, capsules, or powders. These products are significantly more potent than standard kratom leaf powder, which is why they’ve drawn both a dedicated following and increasing scrutiny from regulators.
MIT45 and Mitragynine-Enriched Products
MIT45 is a commercial kratom brand built around concentrated extracts rather than raw leaf material. Their product line includes liquid shots, extract capsules, and their flagship MIT45 Gold. The capsules contain concentrated kratom extract, not the ground leaf powder you’d find in a typical kratom product. The liquid shots pack that same concentrated extract into a small, single-serve bottle.
The “MIT” in the name comes from mitragynine, the dominant alkaloid in kratom leaves. In standard kratom leaf powder, mitragynine makes up roughly 1 to 6% of the product by weight. A study of wild kratom trees in Thailand found leaf concentrations ranging from about 0.75% to 2.7% of dry weight, with an average around 1.6%. Extract products concentrate this alkaloid well beyond those natural levels, which is what makes them hit harder and faster than plain leaf powder.
How Mitragynine Works in the Body
Mitragynine is classified as an indole alkaloid, and it interacts with the same receptors in the brain that opioid drugs target. It binds most strongly to the mu-opioid receptor, the same one activated by morphine and fentanyl, though its binding affinity is roughly 89 times weaker than morphine’s at that receptor. It has even less activity at the body’s other two opioid receptor types.
What makes mitragynine pharmacologically unusual is that it acts as a partial agonist at the mu receptor, activating it to only about 34% of its full capacity. For comparison, morphine and fentanyl are full agonists that push that receptor much closer to maximum activation. This partial activation is why kratom produces milder effects than prescription opioids and why withdrawal symptoms tend to be less severe. At low doses, mitragynine acts more like a stimulant, increasing energy and reducing fatigue. At higher doses, the opioid-like effects become more prominent, producing pain relief and sedation.
Kratom’s effects kick in within minutes and typically last a few hours.
Mitragynine vs. 7-Hydroxymitragynine
Kratom contains dozens of alkaloids, but the two that matter most are mitragynine and 7-hydroxymitragynine (often called 7-OH). Mitragynine is the heavyweight by volume, making up about 66% of the total alkaloid content in kratom leaves. 7-OH accounts for only about 2%, but it punches far above its weight.
In lab studies, 7-hydroxymitragynine is roughly 10 times more potent than mitragynine at the mu-opioid receptor and about 13 times more potent than morphine in certain tissue tests. Unlike mitragynine, 7-OH is a true partial agonist with meaningful receptor activation, not just weak binding. This potency difference matters because some extract products, including certain MIT-branded ones, can end up with elevated levels of 7-OH through the concentration process. The body also naturally converts some mitragynine into 7-OH during metabolism.
Interestingly, animal research suggests the two compounds have very different effects on the brain’s reward system. Morphine lowered reward thresholds in rats, a sign of pleasurable effects, while high doses of 7-hydroxymitragynine actually raised those thresholds, suggesting it may produce aversive rather than rewarding effects at higher concentrations. Mitragynine itself had minimal impact on reward thresholds in either direction.
How Extracts Are Made
Creating a concentrated kratom extract involves pulling mitragynine and other alkaloids out of raw leaf material using solvents. The most traditional approach is soaking dried leaves in methanol, though manufacturers also use ethanol, water, or combinations of the two. More advanced methods include ultrasound-assisted extraction, microwave-assisted extraction, and supercritical CO2 extraction. Ultrasound extraction with methanol tends to yield the highest mitragynine concentrations, while microwave methods in a water-methanol mix produce the largest overall alkaloid fraction.
After extraction, the solvent is evaporated off, leaving behind a concentrated resin or liquid with mitragynine levels many times higher than the original leaf. This concentrate is then formulated into the capsules, liquid shots, or powders sold under brands like MIT45. The exact concentration varies by product and isn’t always clearly labeled, which is one of the challenges for consumers trying to gauge what they’re actually taking.
Safety Concerns With Concentrated Extracts
The higher potency of MIT-style extracts comes with higher risk. Liver injury is the most documented serious side effect. A review of cases in the Drug-Induced Liver Injury Network found that seven out of eight kratom-related cases had a confirmed causal link. Patients typically developed symptoms like jaundice, itching, abdominal pain, or fever after a median of 22 days of use. All patients in that review recovered, though six required hospitalization. Whether the liver damage comes from mitragynine itself, from 7-OH, or from contaminants introduced during manufacturing remains unclear.
Concentrated extracts also raise the tolerance floor quickly. Because they deliver far more alkaloid per dose than plain leaf, users can develop tolerance faster, making it harder to get the same effects from regular kratom powder and potentially deepening dependence.
Where Regulators Stand
The FDA has taken a targeted approach to kratom regulation, focusing specifically on 7-hydroxymitragynine rather than kratom leaf products as a whole. In 2024, the agency recommended that 7-OH be scheduled as a controlled substance under the Controlled Substances Act. The FDA issued warning letters to seven companies selling products containing concentrated 7-OH, including tablets, gummies, drink mixes, and shots.
The distinction the FDA draws is important: they are not pursuing natural kratom leaf products with this action. The concern is specifically about products with artificially concentrated levels of 7-OH, the kind of potency boost that some extract products deliver. There are no FDA-approved drugs containing 7-OH, and the agency has stated it cannot be lawfully added to dietary supplements or conventional foods. These products remain widely available online and in gas stations, convenience stores, and vape shops despite the warnings.
Extracts vs. Plain Leaf Kratom
The core difference between MIT-style extracts and standard kratom powder is concentration. A teaspoon of plain kratom leaf powder contains mitragynine in the low single-digit percentage range. An extract capsule or liquid shot can contain many times that amount in a much smaller volume. This makes dosing less predictable, especially since product labeling across the kratom industry is inconsistent. Two “extract” products from different brands might contain wildly different amounts of mitragynine and 7-OH.
For someone used to plain leaf kratom, switching to an extract product without adjusting expectations can lead to unexpectedly strong effects, including heavy sedation, nausea, or the kind of opioid-like experience that plain leaf rarely produces. The reverse is also true: someone who builds tolerance on extracts may find plain leaf ineffective, which can create a cycle of escalating use.