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Methamphetamine

Methamphetamine molecule structureMethamphetamine molecule structure
N-Methylamphetamine
Meth, Crystal, Ice, Glass, Shard
Psychoactive Class

Methamphetamine is a potent synthetic stimulant of the substituted amphetamine class. First synthesized in 1893 by Japanese chemist Nagayoshi Nagai, it saw widespread use during World War II to combat fatigue and was later prescribed for obesity and attention deficit disorder under the brand name Desoxyn.citation needed Because it is more lipid-soluble than amphetamine, it enters the brain faster. Methamphetamine carries a significant risk of addiction and remains widely used as a street drug.

Dosage & Duration

Dosage

Doses are population estimates that vary widely between individuals.

Threshold~5 mg
Light5-15 mg
Moderate15-30 mg
Strong30-60 mg
Heavy60+ mg
Bioavailability
67%

Duration

Onset20-45 minutes
Come Up1-3 hours
Peak3-5 hours
Offset3-4 hours
After Effects6-24 hours
Half-life
5-30 hours (average 9-12 hours)1

Subjective Effects

Legacy content. A statistically backed ontology from Mindstate Design Labs is coming soon.

Effects vary widely by individual, dose, and context.

Physical

The physical effects of Methamphetamine can be broken down into several components which progressively intensify proportional to dosage.

Cognitive

The cognitive effects of methamphetamine can be broken down into several components which progressively intensify proportional to dosage. The general head space of methamphetamine is described by many as one of extreme mental stimulation, increased focus, and powerful euphoria. It contains a large number of typical stimulant cognitive effects. Although negative side effects are usually mild at low to moderate dosages, they become increasingly likely to manifest themselves with higher amounts or extended usage. This particularly holds true during the offset of the experience.

Forked from Subjective Effect Documentation byJosie Kins September 2015.

Reagent Testing

Expected colorimetric results for common reagent tests. Colors show reaction change over 1–2 minutes.

Marquis(MQ)
white → yellow2 → orange2 → red2 → brown2
Mecke(ME)
white → yellow1 → yellow2
Mandelin(MD)
yellow2 → green3
Liebermann(LB)
white → orange2 → red2
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Pharmacology

Pharmacodynamics

Methamphetamine acts primarily as a potent releasing agent of dopamine, norepinephrine, and to a lesser extent serotonin through several converging mechanisms. As a potent full agonist at trace amine-associated receptor 1 (TAAR1), it induces phosphorylation and functional reversal of monoamine transporters on the cell membrane, driving neurotransmitter efflux into the synaptic cleft.citation needed It also inhibits vesicular monoamine transporter 2 (VMAT2), preventing monoamine storage in synaptic vesicles and promoting their release into the cytosol. Additional contributing mechanisms include increased intracellular calcium driving dopamine transporter phosphorylation, enhanced expression of the dopamine-synthesizing enzyme tyrosine hydroxylase, and reduced surface expression of dopamine transporters. Methamphetamine also acts as an agonist at alpha-2 adrenergic and sigma receptors (with greater affinity for σ1 than σ2) and inhibits both monoamine oxidase A and B.

Pharmacokinetics

Methamphetamine is metabolized primarily by the liver enzyme CYP2D6, with amphetamine and 4-hydroxymethamphetamine as its principal metabolites. Several additional minor metabolites are produced, a number of which retain sympathomimetic activity. Methamphetamine is itself a CYP2D6 inhibitor, and co-administration of other CYP2D6 inhibitors prolongs its elimination half-life. The elimination half-life averages 9 to 12 hours but ranges broadly from 5 to 30 hours. Oral bioavailability is approximately 67%, rising to 79% via the intranasal route and 67 to 90% when smoked, with complete bioavailability when administered intravenously.

Interactions

Dangerous

Highest risk

These combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.

Unsafe

Avoid

There is considerable risk of physical harm when taking these combinations, they should be avoided where possible.

2C-T-x compounds5-MeO-xxT tryptaminesDOx compoundsDXMNBOMe compoundsPCPPregabalin

Caution

Use caution

These combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.

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Tolerance

Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.

Full Tolerance
Repeated methamphetamine use over time can produce rapid tolerance, causing users to need larger doses for similar effects. Euphoria fades especially quickly, often becoming much weaker after the first few uses or after several doses in succession. Subjective effects such as empathy enhancement and openness also tend to vanish early, once initial exposures or broader tolerance have occurred. Chronically tolerant users may require dosages 2-3 times higher than amounts effective for naive users.
Baseline Reset
1-2 weeks in the absence of further consumption, though recovery for heavy users can take significantly longer, potentially years for full normalization of reward sensitivity.
Half Tolerance
3-7 days
Cross Tolerance

Dopaminergic stimulants

Harm Potential

Addiction & Dependence

Psychological

Extremely High

Methamphetamine is widely considered one of the most addictive substances due to the intense euphoria it produces. It has extremely high abuse liability with strong compulsive redosing patterns, particularly when vaporized or injected. The drug produces powerful cravings and psychological dependence develops readily with repeated use.

Physical

High

Physical dependence develops with regular use. Withdrawal symptoms occur in up to 87.6% of chronic high-dose users and persist for three to four weeks with a marked crash phase in the first week. Symptoms include anxiety, drug craving, dysphoric mood, fatigue, increased appetite, lack of motivation, and vivid dreams. Depression from methamphetamine withdrawal lasts longer and is more severe than that of cocaine withdrawal.

Toxicity

Central Nervous System

At moderate to heavy recreational doses, methamphetamine is directly neurotoxic to dopaminergic and serotonergic neurons, causing adverse changes in brain structure and function including reductions in grey matter volume. Chronic abuse is associated with an increased risk of Parkinson's disease.

Cardiovascular

Methamphetamine produces vasoconstriction, tachycardia, and hypertension, with elevated risk of stroke and heart attack.citation needed Abnormal heartbeats and irregular heart rhythms may be life-threatening. Chronic consumption is associated with brain hemorrhages and coronary atherosclerosis.

Renal

Kidney damage and fatal kidney disorders have been reported with chronic use. Kidney failure may occur in overdose situations.

Hepatic

Liver damage has been associated with chronic methamphetamine use.

Pulmonary

Fatal lung disorders and pulmonary fibrosis have been associated with chronic use. Pulmonary hypertension may occur in overdose.

Dental and Oral

Heavy users may lose their teeth abnormally quickly regardless of route of administration, a condition known as meth mouth. This is caused by poor oral hygiene, dry mouth, teeth grinding, and the habit of consuming sugary beverages to relieve dry mouth symptoms.

Integumentary

Long-term users may develop skin sores from scratching due to itchiness or delusional parasitosis, compounded by poor diet and hygiene.

Musculoskeletal

Rhabdomyolysis may occur during overdose or extended binges.

Psychosis Risk

Chronic high-dose use can induce stimulant psychosis presenting with paranoia, hallucinations, delusions, and delirium. This is similar to paranoid schizophrenia and may include bizarre and violent behavior. About 5-15% of users who develop amphetamine psychosis fail to recover completely. Symptoms are magnified by sleep deprivation which commonly accompanies heavy use. Psychosis very rarely arises from therapeutic use.

Seizure Risk

Seizures are an uncommon effect but can occur in those predisposed to them, especially during physical stress such as dehydration, fatigue, or malnourishment, or with extended misuse. Death from methamphetamine poisoning is typically preceded by convulsions and coma.

History & Culture

Discovery and Early Synthesis

The development of methamphetamine followed shortly after the creation of its parent compound. Romanian chemist Lazăr Edeleanu first synthesized amphetamine in Germany in 1887, naming it phenylisopropylamine. Six years later, Japanese chemist Nagai Nagayoshi achieved the first synthesis of

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Legality

International

UN Convention on Psychotropic Substances 1971: Schedule II

By Country

Illegal15
Austria flagAustriaIllegal
Brazil flagBrazilIllegal
Canada flagCanadaIllegal
Czech Republic flagCzech RepublicIllegal
France flagFranceIllegal
Germany flagGermanyIllegal
Israel flagIsraelIllegal
Japan flagJapanIllegal
Netherlands flagNetherlandsIllegal
New Zealand flagNew ZealandIllegal
Norway flagNorwayIllegal
Philippines flagPhilippinesIllegal
Russia flagRussiaIllegal
South Korea flagSouth KoreaIllegal
United Kingdom flagUnited KingdomIllegal
Controlled / restricted1
Colombia flagColombiaRestricted
Prescription10
United States flagUnited StatesPrescription only
Argentina flagArgentinaPrescription only
Australia flagAustraliaPrescription only
Denmark flagDenmarkPrescription only
Ireland flagIrelandPrescription only
Poland flagPolandPrescription only
South Africa flagSouth AfricaPrescription only
Spain flagSpainPrescription only
Sweden flagSwedenPrescription only
Switzerland flagSwitzerlandPrescription only
Legal / decriminalized1
Italy flagItalyDecriminalized

References

Source Pages

  1. Drug Users Bible by Dominic Milton Trott
  2. DrugBank: Methamphetamine
  3. Erowid
  4. Isomer Design (TiHKAL/PiHKAL)
  5. PsychonautWiki
  6. The Drug Classroom
  7. TripSit Factsheets
  8. TripSit Wiki
  9. Wikipedia

Citations

  1. Leo J. Schep, Robin J. Slaughter, & D. Michael G. Beasley. (2010). The clinical toxicology of metamfetamine. Clinical Toxicology. https://doi.org/10.3109/15563650.2010.5167521
  2. Ley 19.303, Régimen de Psicotrópicos. anmat.gob.ar (n.d.). https://www.anmat.gob.ar/webanmat/Legislacion/Medicamentos/ley19303.pdf1
  3. Ley 19.303, Régimen de Psicotrópicos. e-legis-ar.msal.gov.ar (n.d.). https://e-legis-ar.msal.gov.ar/htdocs/legisalud/migration/pdf/6379.pdf1
  4. Therapeutic Goods (Poisons Standard—June 2025) Instrument 2025; ACT drug-law reform. legislation.gov.au (n.d.). https://www.legislation.gov.au/F2025L00599/asmade/2025-05-28/text/original/epub/OEBPS/document_1/document_1.html1
  5. Therapeutic Goods (Poisons Standard—June 2025) Instrument 2025; ACT drug-law reform. act.gov.au (n.d.). https://www.act.gov.au/health/drugs-alcohol-smoking-and-vaping/drug-law-reform1
  6. Suchtgiftverordnung (SV), Anhang IV, under the Suchtmittelgesetz (SMG). ris.bka.gv.at (n.d.). https://ris.bka.gv.at/NormDokument.wxe?Abfrage=Bundesnormen&Anlage=4&Artikel=&FassungVom=2026-01-13&Gesetzesnummer=10011053&Paragraf=&ShowPrintPreview=True&Uebergangsrecht=1
  7. Suchtgiftverordnung (SV), Anhang IV, under the Suchtmittelgesetz (SMG). ris.bka.gv.at (n.d.). https://ris.bka.gv.at/NormDokument.wxe?Abfrage=Bundesnormen&Anlage=&Artikel=&FassungVom=2026-02-07&Gesetzesnummer=10011040&Paragraf=1&Uebergangsrecht=1
  8. PubChem PUG REST compound properties — methamphetamine. pubchem.ncbi.nlm.nih.gov (n.d.). https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/name/methamphetamine/property/IUPACName,CanonicalSMILES,IsomericSMILES,MolecularFormula/JSON12
  9. PubChem PUG REST synonyms — methamphetamine CID 10836. pubchem.ncbi.nlm.nih.gov (n.d.). https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/name/methamphetamine/synonyms/JSON12
  10. Portaria SVS/MS nº 344, de 12 de maio de 1998 — current consolidated text. anvisalegis.datalegis.net (n.d.). https://anvisalegis.datalegis.net/action/ActionDatalegis.php?acao=abrirTextoAto&tipo=POR&numeroAto=00000344&seqAto=000&valorAno=1998&orgao=SVS/MS&codTipo=&desItem=&desItemFim=&cod_menu=1696&cod_modulo=134&pesquisa=true1

Further Reading

  1. DrugWise: Methamphetamine
  2. Nestler et al. 2009 - Molecular Neuropharmacology

Article Status

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Recent changes7 human edits · latest

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24 January 2026

  1. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  2. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  3. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  4. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  5. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  6. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  7. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

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