Short answer: Methamphetamine is a powerful stimulant. A prescription form, Desoxyn, is approved for ADHD but rarely used. Nearly all methamphetamine in the US is made illegally as crystal or powder, and it is increasingly involved in overdose deaths, often together with fentanyl. It is a Schedule II controlled substance.
Key takeaways
- What it is: Methamphetamine is an amphetamine-type stimulant and a Schedule II controlled substance in the US.
- Medical use: ADHD (Desoxyn, rarely).
- Timing: effects start in seconds to 20 minutes and last 8 to 24 hours.
- Most dangerous mix: MAOIs, which can cause dangerous rise in blood pressure.
- Naloxone: it does not reverse this drug, but give it whenever opioids could be involved.
- Dependence risk: Very high.
- Legal route: no approved US product for personal use; possession without a prescription is a crime.
What is methamphetamine?
Methamphetamine is chemically close to amphetamine but enters the brain faster and releases more dopamine, which makes it more euphoric and more addictive. Desoxyn tablets are FDA-approved for ADHD but are rarely prescribed.
Methamphetamine causes intense euphoria, alertness, energy, talkativeness, reduced appetite, faster breathing and heart rate, higher blood pressure, and raised body temperature.
Quick facts
| Fact | Methamphetamine |
|---|---|
| Chemical name | Methamphetamine (N-methylamphetamine) |
| Prescription brand | Desoxyn (rarely prescribed) |
| Street names | Meth, crystal, ice, crank, glass, Tina |
| Drug class | Amphetamine-type stimulant |
| US legal status | Schedule II; illicit manufacture and sale are federal crimes |
| How it is used | Smoked, snorted, injected, or swallowed |
| Onset | Seconds (smoked or injected) to 20 minutes (swallowed) |
| Duration | 8 to 24 hours |
| Half-life | About 10 hours |
How long does methamphetamine last?
- Starts working: Seconds to 20 minutes
- Effects last: 8 to 24 hours
- Half-life: About 10 hours
Its half-life is about 10 hours. Urine tests detect it for 2 to 4 days, longer after heavy use.
Timing varies with the dose, the form, how it is taken, liver and kidney function, age, and other drugs taken at the same time.
What are the biggest risks of methamphetamine?
Heart and brain: heart attack, dangerous heart rhythms, heart failure, stroke, and very high body temperature.
Mental health: anxiety, paranoia, hallucinations, aggression, and psychosis that can persist after use stops.
Physical: severe dental decay ("meth mouth"), skin sores from picking, weight loss, and HIV and hepatitis risk from injection and sexual behavior.
Warning: Fentanyl is increasingly found in methamphetamine. People who do not use opioids have no tolerance, so even small amounts of fentanyl can be fatal. Carry naloxone and use fentanyl test strips.
What should you never mix with methamphetamine?
| Combined with | What happens | Risk level |
|---|---|---|
| Fentanyl and other opioids | Overdose; opioid effects hit when meth wears off | Leading cause of stimulant-involved deaths |
| Other stimulants (cocaine, MDMA, ADHD medicines) | Extreme heart strain, overheating | Very high risk |
| MAOIs | Dangerous rise in blood pressure | Potentially fatal |
| Alcohol | Masks drunkenness, leading to alcohol poisoning; heart strain | High risk |
| SSRIs, MDMA, tramadol | Serotonin syndrome | High risk |
Check any combination with the DoseUses combination checker or ask a pharmacist.
What are the signs of a methamphetamine overdose, and what should you do?
Methamphetamine overdose can cause chest pain, very fast or irregular heartbeat, very high body temperature, severe agitation or paranoia, seizures, stroke, and collapse. Many overdose deaths involving methamphetamine also involve fentanyl.
If someone may be overdosing
- Call 911 for chest pain, a seizure, trouble breathing, signs of a stroke (face drooping, weakness on one side, slurred speech), a very high body temperature, or if the person collapses.
- Move them somewhere cool and calm, loosen tight clothing, and cool the skin with water. Do not try to hold them down.
- If they become unresponsive or their breathing slows, give naloxone. Street stimulants are often contaminated with fentanyl.
- For advice when the person is awake and stable, call Poison Help at 1-800-222-1222.
Is methamphetamine addictive, and what is withdrawal like?
Methamphetamine is highly addictive. Withdrawal is not usually physically dangerous but is intensely unpleasant and a common trigger for relapse.
- Days 1 to 3CrashExhaustion, very long sleep, hunger, low mood.
- Weeks 1 to 2Acute withdrawalDepression, anxiety, irritability, poor concentration, strong cravings.
- Weeks to monthsRecoveryCravings and low mood can persist for months; brain changes partly recover with time.
See the withdrawal timelines and the full methamphetamine withdrawal guide.
Is methamphetamine legal?
Methamphetamine is Schedule II: it has a recognized medical use as Desoxyn, but making, selling, or possessing it without a prescription is a federal crime. Pseudoephedrine, a precursor, is sold behind the pharmacy counter with ID and monthly limits under the Combat Methamphetamine Epidemic Act.
- Possession: under federal law, a first conviction for possessing any controlled substance without a valid prescription can bring up to one year in prison and a minimum fine of $1,000. Penalties rise with prior convictions.
- Trafficking: trafficking 5 grams or more of pure methamphetamine, or 50 grams or more of a mixture, carries a mandatory minimum of 5 years in federal prison; ten times those amounts carries 10 years.
- State law: states set their own penalties, and most drug cases are prosecuted under state law. Penalties range from a civil fine to long prison terms depending on the state, the amount, and prior record.
Outside the United States
| Country | Status |
|---|---|
| United Kingdom | Class A |
| Canada | Schedule I |
| Australia | Schedule 9 prohibited substance |
| International | Schedule II of the 1971 Convention on Psychotropic Substances |
Frequently asked questions about methamphetamine
Is methamphetamine ever prescribed?
Yes, as Desoxyn for ADHD, but very rarely. Other stimulants are preferred.
How long does meth stay in your system?
Its half-life is about 10 hours. Urine tests detect it for 2 to 4 days, longer after heavy use.
Is there a medicine to treat meth addiction?
No medicine is FDA-approved yet. Contingency management works best, and a combination of naltrexone and bupropion helped in a large trial.
Can naloxone reverse a meth overdose?
No, but give it anyway if the person is unresponsive or not breathing well, because fentanyl is often present.
What is "meth mouth"?
Severe tooth decay and gum disease from dry mouth, teeth grinding, and poor hygiene during heavy use.
Sources
- Desoxyn (methamphetamine) prescribing information, DailyMed, US National Library of Medicine.
- Methamphetamine DrugFacts, National Institute on Drug Abuse.
- Controlled Substance Schedules, DEA Diversion Control Division.
- 21 U.S.C. 844, Penalties for simple possession, Legal Information Institute, Cornell Law School.
- 21 U.S.C. 841, Prohibited acts A (trafficking penalties), Legal Information Institute, Cornell Law School.
- National Helpline, Substance Abuse and Mental Health Services Administration.
- FindTreatment.gov, Substance Abuse and Mental Health Services Administration.
- International drug control conventions, United Nations Office on Drugs and Crime.
This guide summarizes the sourced DoseUses Methamphetamine profile, written from FDA labels, DEA rules, and federal health agencies. It is educational and is not medical advice. Last updated October 5, 2026.
