Methamphetamine — overview, properties, medical use, risks and history

Properties, forms and routes

The compound can appear as a white or yellowish powder, crystalline chunks or small shards. In common usage the crystalline form is often called "crystal meth." It is sold under a variety of street names and can be consumed in several ways.

• Common forms: powder and crystal.
• Routes of administration: snorting, smoking, intravenous injection and oral ingestion.
• Street names: ice, crystal, crank, glass and other regional names.

Isomers and legal distinctions

Chemically, methamphetamine has two enantiomers. One enantiomer is used in some over‑the‑counter decongestants and other remedies in certain countries, while the other — the one most associated with stimulant effects and euphoria — is the predominant form in illicit products. The psychoactive enantiomer is generally subject to strict controls and criminal penalties in many jurisdictions because of its abuse potential and harms to individuals and communities. For clarity, when the article discusses recreational misuse it refers primarily to that psychoactive form.

Medical use and regulation

Methamphetamine has a small number of accepted medical indications in some countries when prescribed at low, regulated doses. Under medical supervision it has been used for attention‑deficit/hyperactivity disorder (ADHD) and, historically, for short‑term management of certain cases of obesity. A pharmaceutical product exists in markets as a controlled prescription formulation and is provided only when other treatments are not suitable; such use is tightly regulated and monitored via prescription programs and scheduling laws (prescription).

Effects, dependence and health risks

Acute effects include increased wakefulness, elevated heart rate and blood pressure, reduced appetite, heightened confidence and, in high doses, agitation or psychosis. Repeated use can produce tolerance, dependence and a pattern of compulsive use. Methamphetamine is considered highly addictive compared with many other substances. Long‑term misuse is linked with significant harms: cognitive and emotional changes, dental problems, skin sores, infectious disease risks from injection, cardiovascular complications and increased risk of psychiatric disorders.

Illicit manufacture, environmental harm and legal response

Illicit production methods vary by region and often involve hazardous chemicals and improvised laboratory processes. These processes present risks of explosions, toxic exposures and environmental contamination. Because of the criminal nature of most production and distribution, law enforcement and public‑health agencies coordinate efforts to reduce supply, support treatment services and limit harm. Possession, distribution and manufacture are criminalized in many jurisdictions, and actions taken against illegal operations can be severe (illegal).

Public health, treatment and harm reduction

Addressing methamphetamine use involves a mixture of prevention, treatment and harm‑reduction strategies. Evidence‑based treatment approaches include behavioral therapies and psychosocial support; there is ongoing research into pharmacological aids. Harm‑reduction measures — such as providing sterile injecting equipment, education on safer use and access to medical care — aim to reduce immediate risks while connecting people to longer‑term services. Public‑health responses balance law enforcement, treatment access and community education to limit the drug's individual and societal impact.

For general reference about stimulants and controlled medicines see related resources: stimulant overview, controlled substances, and information on legal prescriptions and public‑health programs (prescription, ADHD, obesity, illegal market, addiction, powder, crystal).