Description
Heroin is the popular name for diamorphine. It acts as a depressant, so it slows down functions and reactions in the body and is also a strong pain killer (analgesic). Discovered in 1874, it comes from the opium poppy.
Heroin can be a highly dependence-forming drug, producing tolerance to its effects and deep physical dependence—without it the user becomes ill and unable to function normally. It should also be noted that the drug is especially effective at reducing psychological and emotional pain, and most people dependent on heroin can be accurately described as people self-medicating against traumatic memories and intolerable feelings. The time taken to become dependent varies with the individual and context, as does the severity of withdrawal symptoms. Overdose can be fatal, of course, and most overdoses are due to profound depression of the respiratory system. After many years of abundant supply at user-end purity, in the UK heroin quality now varies significantly.
Pharmaceutical grade heroin is called diacetylmorphine or diamorphine. ‘Heroin’ refers to the illicit type, originating from the Golden Triangle (Thailand, Laos and Myanmar) and is usually (off) white. Most of the heroin available in the UK comes from The Golden Crescent (Afghanistan, Iran and Pakistan), and is a base form of the drug (an intermediary stage in the production process to the salt form). This makes it suitable for smoking, and much illicit heroin is smoked on tin-foil (‘chasing the dragon’ or ‘booting’).
The salt form of diamorphine/heroin is very soluble, and the base (usually a brown powder) can also be injected, but requires an acidifier and heat to make it dissolve (citric acid or vitamin C typically). For more advice, including harm reduction, see our safer injecting guidance.
Desirable Effects
- Powerful euphoriant
- Relaxing effects
- Feelings of wellbeing and freedom from worry
Undesirable Effects
- Nausea and vomiting
- Loss of balance and coordination
- Severe respiratory depression (overdose can be fatal)
- Constipation and reduced libido
What does it look like?
While pharmaceutical heroin is white, most of the illicit heroin available in the UK is a brownish or beige powder.
Method of Use
Smoked: Brown heroin base is most suitable for smoking. Much illicit heroin is smoked on tin-foil (‘chasing the dragon’ or ‘booting’).
Injected: Brown heroin can also be injected, but needs an acidifier (such as sterile citric acid or vitamin C) and heat to dissolve. For more information, see our safer injecting guidance.
Snorted: Lumps are crushed into powder and snorted (insufflated) via rolled-up paper or ‘bumped’/’keyed’ in small amounts.
Pharmacology
Heroin is a relatively weak opioid itself and instead mainly acts as an opioid pro-drug: after efficiently crossing the blood-brain barrier, it is rapidly metabolised into the more potent µ-opioid agonists 6-monoacetylmorphine (6-MAM) and morphine, which then bind to opioid receptors resulting in the drug’s euphoric, anxiolytic (reducing anxiety), and painkilling effects.
Prolonged heroin use can lead to desensitisation and downregulation of the µ-opioid receptors, requiring higher doses to achieve the same effects. If after repeated use the individual suddenly stops ‘cold turkey’, they will have fewer, less responsive opioid receptors, leading to a reduction in the body’s response to endorphins which causes withdrawal symptoms or ‘dope sickness’. This can leave people feeling worse than they did prior to using heroin and may cause physical dependence, resulting in further use in an attempt to alleviate withdrawal.
Taking heroin in combination with other depressants dramatically increases the risk of fatal overdose. Drinking alcohol or taking benzodiazepines, Z-drugs, or gabapentinoids alongside heroin causes compounding sedation and slows breathing to dangerous levels. Naloxone is an opioid antagonist that reverses the effects of an opioid overdose; to find out how naloxone works and where to get free kits, visit our Naloxone guidance page.
History
While the synthesis of diacetylmorphine dates to 1874 (first synthesised by C.R. Alder Wright in Paddington, London, and commercially launched in 1899 by Bayer in Germany under the trademark ‘Heroin’), opium itself has a millennia-long history of social and medical use.
The prohibition and criminalisation of opium in the early 20th century inadvertently accelerated the adoption of heroin as a more concentrated, easily trafficked alternative. This shift replaced traditional cultural contexts with a rapid black market and introduced injecting as a cost-effective administration method, bringing severe public health consequences including blood-borne virus transmission and escalating overdose rates.
For decades, the UK pioneered the controlled prescribing of pharmaceutical diamorphine to dependent individuals under what became known internationally as ‘The British System’. Today, diamorphine remains a licensed prescription medicine in the UK for severe pain and palliative care, while specialist doctors require a Home Office licence to prescribe it for opioid dependence.
Law
Class A under the Misuse of Drugs Act 1971.
Schedule 2 under the Misuse of Drugs Regulations 2001.
Possible offences
- Possession: Maximum sentence of up to 7 years imprisonment, an unlimited fine, or both.
- Possession With Intent To Supply (PWITS): Maximum sentence of up to life imprisonment, an unlimited fine, or both.
- Supply: (including being concerned in supply, conspiracy to supply, aggravated supply, and offer to supply) Maximum sentence of up to life imprisonment, an unlimited fine, or both.
- Production: Maximum sentence of up to life imprisonment, an unlimited fine, or both.
In practice, maximum sentences are rarely imposed, particularly for simple possession. For detailed guidance on sentencing guidelines and thresholds, visit our Drugs Law & Rights section.
