How pure are drugs?

It is a truism that there is no such thing as quality control in the illicit market. Often the street seller doesn’t know the drug content of the goods they offer so what chance the buyer or the drug service?

Impure street drugs can be dangerous but these dangers are sometimes exaggerated. There is a degree of urban mythology about street drugs the main one being that drugs are cut with substances such as rat poison, strychnine and brick dust. Such contamination is rare. Unless a dealer has some score to settle, it is not in their best interests to have customers dropping dead from deliberately contaminated drugs.

There is no comprehensive list of what has been added to street drugs. Most drug testing is done for police and Customs who only need to identify what (if any) controlled drugs are present. As testing is an expensive business, laboratories are rarely asked for detailed information about other substances.

A note on terminology

Words such as adulterant’ and impurities’ are used interchangeably to denote that something other than the pure drug is being sold. However, these words do have more specific meanings, as follows:


Substance or substances present in the drug as a natural result of the manufacturing process rather than deliberately added, eg, opiate alkaloids from the process of refining opium into heroin or the by-products of manufacturing amphetamine.


Psychoactive drugs deliberately added to mimic’ the effects of the drug being offered. This would include the stimulants caffeine and ephedrine that make up much of what is passed off as amphetamine. Invariably this is done to increase profits.


Inert substances such as sugars (glucose, lactose or mannitol) added both to bulk out the deal and assist the process of dilution for injection.


Mainly relates to tablet/pill manufacture; the starch or gums used to bind the drug together in tablet form. For the purpose of this entry, the word impurities’ will be used to cover all these.

Batch to batch variation

There are two main types of impurity. First, substances which are psychoactive but are not the ones the buyer was expecting. Second, substances which are virtually or completely inert. Sometimes (but more rarely) drugs are mixed together and sold not as one or the other but as a new’ product. A recent example in London was Wham’, a combination of amphetamine, cocaine and paracetamol.

Drugs are often cut simply to improve profit margins. But there are a number of other reasons why they may not be as advertised or may vary in content. For example, this week’s batch of Love Doves (an ecstasy brand name’) may be of a particular strength or composition; next week’s may be entirely different. This could be because there was a supply problem with one or more of the chemicals used to produce the drug ( precursors’) so substitutes were used. It could instead (or as well) be due to some error in the manufacturing process, or just that the Loves Doves of one week are MDMA (ecstasy) and next week’s are MDEA (a different chemical from the same family of drugs).

Drug content guidelines

The following is a very rough guide to average purities of street drugs and what they contain. This should not be relied on to determine the content of substances actually circulating in any given area.


By a long way, the most impure drug on the market. Average purity is usually less than 5 per cent with samples as low as 1 per cent seen recently. The main cutting agents are sugars, followed by caffeine and ephedrine.


Anything between 20-90 per cent pure averaging around 45-50 per cent with the rest mainly made up of sugars.


Typically 85-95 per cent pure cocaine freebase and up to 100 per cent in some samples. Sophisticated production techniques mainly washing’ with solvent before or after heating mean that high purity drug can be produced from only moderately pure cocaine powder.


Typically 30-80 per cent pure, averaging around 45-50 per cent, though some samples test as low as 25 per cent. The main adulterant is paracetamol, along with other opiate alkaloids and sometimes methaqualone and diazepam. Sugars too are sometimes used to bulk out the product.


Received wisdom is that ravers are turning away from E’ because of poor quality and expense compared with, say, LSD. Recent analyses show some samples containing ketamine and similar drugs also samples with amphetamine, caffeine and other stimulants, and the benzodiazepine sleeping pill’ flunitrazepam. However, most samples contain MDMA or related drugs such as MDA and MDEA even if in sub-active doses. So the main problem is likely to be lack of effect rather than an unexpected one. However, one recent sample did contain more than double the active dose of MDA.


Usually sold as small paper squares cut from a larger sheet which has been soaked in the drug. Mostly the genuine article though completely inert fakes are not unknown. Dosage can vary significantly depending, for example, on how the paper sheets have been prepared.

Anabolic steroids

Most steroids bought in gymnasia are either fakes or counterfeits. Fakes contain little or no steroid (though sometimes they do contain drugs other than steroid) or a different steroid from that cited on the label. Counterfeits are illicitly manufactured products sold as the genuine pharmaceutical drug.

How can you tell what it is?

Is there any way the drug user can test the drug they have bought or that parents or professionals can get drugs they have found tested?

The federal drug police in America use field testing kits, but they contain dangerous substances like acids and are unlikely ever to be made generally available. As long as they do so without delay, a parent or worker can take a sample to the police and ask for it to be tested. Some laboratories will test substances at a price but if the substance is a controlled drug then under certain circumstances the person who took the drug to the laboratory, and the laboratory analysts, may open themselves up to a successful prosecution for unauthorised possession of the drug.