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    Disclaimer
    🧪 This is a research chemical with limited data on its long-term health effects, toxicity profile, and safe dosage ranges.
    ⚠ Opioids carry significant risk of respiratory depression, physical dependence, and fatal overdose. Never combine with other depressants.

    Levomethorphan Encyclopedic
    Encyclopedic
    Typical encyclopedia coverage. Cross-reference for important decisions.
    • 2 corroborating sources
    • 1 ROA with full dose ladder
    • duration data present
    • 29 combo interactions documented
    • PubChem toxicity data
    • classified Research-chemical
    • dose data not in PW/TripSit (unverifiable)

    Aliases: Lvm, Ro 1-5470/6, L-methorphan

    Depressant Research-chemical Opioid

    Summary dose.wiki

    Levomethorphan is a potent opioid analgesic that has never been marketed pharmaceutically. It is the L-stereoisomer of racemethorphan and acts as a prodrug to levorphanol, being demethylated by liver enzymes to its active form. Approximately five times more potent than morphine, levomethorphan carries significant risks of respiratory depression, addiction, and overdose.

    Dose Information Drugs.Wiki

    Dose basis. The dose figures on this page are not clinical data. They are aggregated from community reports by a secondary source whose own notes state there is no human pharmacokinetic study behind them, and our internal audit flags this substance's dosing as unverifiable. Treat them as a rough orientation, not a safe range. Assume full respiratory depression, keep naloxone to hand, never dose alone, and never combine with benzodiazepines, alcohol or other depressants.

    ROA Light Common Strong Heavy
    Oral 2-5mg 5-10mg 10-15mg 15mg+
    Light Common Strong Heavy
    Sources

    Oral

    Dose ladder — Drugs.Wiki

    Onset, Duration & After-effects dose.wiki Drugs.Wiki

    ROA Onset Comeup Peak Offset After Effects Total
    Oral 20-60 min 30-90 min 1-3 hrs 4-6 hrs 2-4 hrs 5.83-11.5 hrs

    Effect Profile

    Scores (0–10) curated from multiple sources:

    • Effect keyword matching from PsychonautWiki catalog
    • Weighted by importance: core (×3), major (×2), minor (×1)

    Full methodology

    Opioid 7.0
    Strong+ 7/10

    Strong euphoria and pain relief with strong itching/nausea, low sedation

    Euphoria / Warmth ×3
    10
    physical euphoria euphoria cognitive euphoria mood lift
    Analgesia ×2
    8
    pain relief analgesia
    Sedation / Relaxation ×1
    3
    sedation
    ⚠ Itching / Nausea ×1
    10
    itching nausea constipation dry mouth
    View methodology →

    Tolerance

    Build-up develops within days of regular use; analgesic tolerance faster than respiratory depression tolerance
    Reset Falls quickly once you stop, at a rate you can't judge. After any break, treat your tolerance as gone.

    No tolerance chart. Our decay curves for opioids were estimates, and a curve can make tolerance look longer-lasting than it is, which is the dangerous direction.

    Opioid tolerance drops fast when you stop, and even a few days off can be enough, so a dose that used to be normal can now stop your breathing. Overdose deaths rise sharply after prison, detox or leaving treatment, and tolerance also falls during a hospital stay. After any break, start with a much smaller amount, try a test dose first, don't use alone, and keep naloxone within reach. Alcohol, benzodiazepines, gabapentinoids and other sedatives make an opioid overdose much more likely.

    Sources: FRANK: heroin · National Harm Reduction Coalition · WHO: opioid overdose · Merrall et al. 2010 · Binswanger et al. 2007 · Strang et al. 2003 · FDA 2019: gabapentinoids and breathing

    Effects dose.wiki

    Positive
    Negative
    Neutral
    Positive
    Negative
    Neutral
    Positive
    Negative
    Neutral
    • Visual and auditory hallucinations

    Combinations

    Cross-Check Levomethorphan with another substance

    Levomethorphan's nerd page Pharmacology, chemical data, effect profiles, and more
    →

    Helpful Links

    📖 dose.wiki
    Add to PsychonautWiki Journal

    The PsychonautWiki Journal logging app doesn't include every substance. To track Levomethorphan there, start adding an ingestion, search for the name, and choose to add it as a custom substance. Paste these values:

    ⬇ Download import file Import this file as custom substances and you get "Levomethorphan (Substance Search)" with every route's full dose ladder and timeline, no typing. Works on iOS and Android (v15+); the format is confirmed by the app's developer. The manual values below work for older versions.
    Name
    Levomethorphan
    Unit
    mg
    Description 
    Levomethorphan
Source: SubstanceSearch (substancesearch.com)

Oral dose (mg): threshold 1-2 · light 2-5 · common 5-10 · strong 10-15 · heavy 15+

Oral duration: onset 0.33-1h · come-up 0.5-1.5h · peak 1-3h · offset 4-6h · total 5.83-11.5h · after-effects 2-4h

Note: ranges are harm-reduction guidance, not a prescription. Start low, go slow, and test your substances.

    Tip: for quicker logging you can also add a Custom Unit in the app, e.g. common dose ~ 7.5 mg (Oral).

    The app keeps custom substances simple, so the full dose ranges live in the description text above. Ranges are harm-reduction guidance, not a prescription.