Mitragynine Pseudoindoxyl (Pseudo).
Mitragynine pseudoindoxyl, often shortened to 'Pseudo' on product labels, is a \u03bc-opioid receptor agonist derived from mitragynine. In animal studies it has been reported as substantially more potent than 7-OH with a distinct receptor-bias profile.
Chemistry
Mitragynine pseudoindoxyl is formed by oxidative rearrangement of mitragynine, replacing the indole nucleus with a pseudoindoxyl (oxindole) framework. The compound was first prepared synthetically and characterized in detail by Váradi, Marrone, and colleagues at Memorial Sloan Kettering [4] as part of a broader investigation into mitragyna alkaloid pharmacology.
Pharmacology in brief
In animal binding and signaling assays, mitragynine pseudoindoxyl is a μ-opioid receptor agonist with potency reported substantially higher than 7-OH and significantly higher than mitragynine itself. The 2016 J Med Chem characterization reported μ agonism with δ-opioid antagonism and reduced β-arrestin-2 recruitment — characteristics that, in the original framing, made it of interest as a potential analgesic with reduced opioid liability. As with SR-17018, the bias hypothesis remains scientifically contested.
Products on the market
Several brands market "Pseudo" tablets — either as standalone products or in combination with 7-OH and/or mitragynine ("7-OH + Pseudo + Mit" blends). See our product library for current listings; filter by compound "Pseudo" on the brand page.
What's not well characterized in humans
- Bioavailability after oral dosing
- Long-term safety profile in humans
- Tolerance and dependence development relative to 7-OH
- Withdrawal characteristics relative to other kratom alkaloids
Legal status
Mitragynine pseudoindoxyl is not specifically scheduled at the federal level in the US as of mid-2026. State-level kratom-restriction laws may or may not cover it depending on how the statute defines kratom alkaloids. The Federal Analogue Act applies. See /Legal.
Related
See /WhatIs7OH for the parent compound, DHM for another mitragynine derivative, and /Compounds for the index of compounds we track.