Medically Reviewed

Adulterants and Additives in Substances

4 min read · 3 sections

Those who use illicit substances run the risk of using drugs adulterated with other substances.1 Adulterants (additives) are frequently mixed with illicit drugs to enhance the potency and effects and bulk up the drug’s quantity to increase profits.1 However, adulterants added to street drugs can magnify the dangers associated with using these drugs, including adverse health consequences such as overdose and death.2

One study tested illicit drugs for adulterants and found that between 89% and 97% of them contained additional substances, including fentanyl, cocaine, heroin, and more.1

This page covers adulterated substances, the dangers associated with these contaminated drugs, and how to get help for a substance use disorder.

What Are Commonly Adulterated Substances?

The term adulterant may be applied to a variety of ingredients used to bulk (or add more weight) to a substance, to enhance or mimic the effects of illicit drugs, or to facilitate the administration of the drug.2 In addition to pharmacologically active ingredients, some substances may be contaminated with manufacturing by-products such as aluminum and lead.2

Research indicates that these substances may be adulterated with a variety of fillers, chemicals, and poisons—from sugars and crushed prescription medications to metals and pesticides.2

Commonly used bulking agents include starch, talc, cellulose, and sugars such as sucrose.2

Additionally, some drugs contain additives that include infectious organisms like bacteria (e.g., Bacillus anthracis (anthrax)) and fungi (Candida).2

What Are the Dangers of Adulterants in Drugs?

Using heroin, cocaine, ecstasy, marijuana, or counterfeit prescription pills each come with a set of risks associated with use. When these substances are “cut” with unknown ingredients, the unexpected adverse effects vary and can be dangerous. Some reported effects include:1

  • Organ damage.
  • Infectious diseases.
  • Blood disorders.
  • Cardiac arrest.
  • Respiratory depression.
  • Death.

Adulterants in Heroin

Over 900,000 individuals aged 12 and older used heroin in 2020.3 According to the Drug Enforcement Administration (DEA), over a 5-year-period from 2013-2017, the heroin purity of seized samples remained consistent—just below 35%—but the price per gram increased.4 The substances often found in heroin include:2,4

  • Fentanyl. Fifty times more potent than heroin, fentanyl is relatively cheap and easy to manufacture. It is commonly added to illicit substances like heroin (and cocaine).5 Furthermore, it takes very little fentanyl to induce a drug overdose. Combining or substituting fentanyl for a drug thought to be heroin can drastically increase the risks of overdose and death. In 2020, about 10,000 heroin overdose deaths in the United States also involved synthetic opioids (primarily fentanyl).6 To help combat unintentional fentanyl overdose, fentanyl strips are readily available and can be used to test whether the illicit drug contains fentanyl, before use.7
  • Caffeine. Caffeine is cheap, legal, and readily available. It is sometimes added to heroin because the caffeine allows vaporization at a cooler temperature when the heroin is smoked, mildly increasing the drug’s effects.8 While caffeine doesn’t carry the risk of overdose like some other adulterants, in large doses caffeine can cause anxiety and mood and sleep disturbances.2
  • Griseofulvin. The bitter-tasting anti-fungal medication may be added to heroin, which is also bitter, to give the impression that the heroin is a purer sample.5
  • Acetaminophen/paracetamol. Like griseofulvin, acetaminophen may mask heroin’s bitter taste. Additionally, acetaminophen has inherent pain-reducing (analgesic) properties and a similar melting point to heroin.5 With concurrent alcohol use, acetaminophen-laced heroin can cause liver damage and gastrointestinal problems.2
  • Phenobarbital. A barbiturate, phenobarbital can compound the risk of respiratory depression—already a danger with heroin alone—overdose and death.2
  • Quinine. An antimalarial medication with a similar bitterness to heroin, quinine may be mixed with the drug to enhance the respiratory “rush” associated with injecting heroin. Quinine toxicity may cause renal failure, gastrointestinal problems, central nervous system overstimulation, visual disturbances (including blindness), overdose, and death.2
  • Noscapine. A by-product of heroin processing, noscapine has been found in heroin samples seized by the DEA. It is believed to magnify the effects of heroin. While it’s typically discarded as waste, some processors reuse it to make a noscapine-enriched powder sold as heroin.4

Adulterants in Cocaine

According to the DEA, the average purity of all cocaine bricks seized in 2018 was 85.4%.4 However, lacing or adulterating cocaine with other substances is not uncommon. Agents commonly added to cocaine include sugars and starches that mimic the white powder. Other adulterants found in cocaine include:2,8

  • Fentanyl. Powdered fentanyl looks just like cocaine, but fentanyl-laced drugs are incredibly potent and dangerous and increase the risk of overdose.5 In fact, the DEA issued a bulletin warning of widespread adulteration of cocaine with fentanyl and fentanyl-related substances in Florida in 2018.9 Additionally, in 2020, roughly 15,000 deaths involving cocaine also involved synthetic opioids (primarily fentanyl).6
  • Lidocaine. A local anesthetic that is more powerful than cocaine’s anesthetic effect, lidocaine is often added to cocaine to potentiate the drug’s effects. This may give the impression that the cocaine is of a higher quality.8 However, the lidocaine addition can have adverse cardiovascular effects even at low doses. Other potential side effects of the combination include nausea, vomiting, dizziness, tremors, and convulsions. Overdose can occur at excessive doses.2
  • Levamisole. A parasite-killing agent used by veterinarians to de-worm cattle, levamisole has been increasingly found as an adulterant in cocaine.2,8 Based on seizure reports, the DEA estimates that more than 80% of the cocaine entering the United States contains levamisole.8 Its physical similarity to powdered cocaine allows it to be used to bulk up the drug, and researchers theorize that the long-acting psychostimulatory effects of levamisole’s metabolite aminorex might prolong cocaine’s stimulatory effects when mixed with it.8

However, levamisole-contaminated cocaine can be highly toxic and cause adverse effects such as headaches, nausea, vomiting, fatigue, fever, diarrhea, dizziness, confusion, and rash.8 Serious complications include blood disorders (such as agranulocytosis, a drug-induced condition characterized by a severe reduction in the number of white blood cells in the body), inflammation of the blood vessels, psychosis, pulmonary hypertension and hemorrhage, skin lesions, arthritis, and death—specifically as a result of damage to the brain, heart, and lungs.8

  • Caffeine. Caffeine is added to cocaine because it’s cheap and widely available. As a stimulant, it may mildly increase the effects of cocaine.8
  • Hydroxyzine. An antihistamine, hydroxyzine may be used in the final stages of the cocaine manufacturing process.2 Adverse effects can include dizziness, drowsiness, gastrointestinal problems, ringing in the ears, and headaches.2
  • Phenacetin. A pain-relieving, fever-reducing drug with similar properties to cocaine, phenacetin was banned by the U.S. Food and Drug Administration (FDA) in 1983, because of its association with kidney failure and its potential to cause cancer. However, research indicates that it is frequently present in cocaine samples.2

Adulterants in MDMA

Individuals who use MDMA risk ingesting unknown substances, which are often found in illicitly purchased ecstasy pills, capsules, tablets, and powders. They may think they’re purchasing ecstasy when they are, in fact, buying other substances instead of or in addition to MDMA.10,11 These substances can vary widely, and may include:

  • Fentanyl. In 2020, more than 10,000 psychostimulant-involved overdose deaths (mostly methamphetamine) also involved synthetic opioids (primarily fentanyl).6
  • Amphetamines. Amphetamines, such as methamphetamine, can produce similar effects to the stimulant properties of ecstasy. Thus, amphetamines are often sold in place of or with MDMA. Moderate doses can produce adverse health effects, including mood disturbances, anxiety, insomnia, and addiction. High doses can cause overdose and death.2
  • Para-methoxyamphetamine(PMA)/para-methoxymethamphetamine (PMMA). Both PMA and PMMA are illicit stimulants that have been detected in samples of MDMA or masqueraded as MDMA entirely. Case reports have found evidence of PMA- and PMMA-related deaths in individuals who use ecstasy.2
  • Dextromethorphan (DXM). An ingredient found in over-the-counter cough suppressants, DXM can cause a “high” similar to ecstasy when taken in high doses due to its dissociative/euphoric effects. However, adverse effects at high doses include drowsiness, elevated heart rate, poor muscle control, involuntary eye movements, and an increased risk of heatstroke.2
  • Ketamine. Ketamine is a dissociative anesthetic with hallucinogenic properties. It is often discovered in contaminated MDMA samples.2
  • Caffeine. Caffeine may be added to MDMA to bulk up the sample and because its stimulant properties may create effects that are similar (but milder) to MDMA.2
  • Eutylone and other synthetic cathinones. Colloquially referred to as bath salts, eutylone and other synthetic cathinones have been detected in MDMA samples. In fact, the supply of eutylone increased so rapidly in the United States from 2017-2021, that authorities issued public alerts about the potential risk of overdose associated with it. Studies show that roughly 1 in 10 eutylone-involved deaths in 2020, had evidence of current or past MDMA use but no toxicology findings of MDMA, which supports the idea that individuals unintentionally ingest eutylone when they think they are taking MDMA.12

Adulterants in Marijuana

Marijuana is less likely to be adulterated than illicit drugs that are sold as powders and tablets.2 However, that doesn’t mean that contaminants have not been found in marijuana samples. These adulterants include:

  • Lead, aluminum, and glass. Lead and glass are presumably added to increase the weight of the product but can lead to lead poisoning and ulcerations of the mouth and a persistent cough, respectively. It is generally unknown why aluminum is added but may be due to impure water sources used during growing. Aluminum can lead to smoking-related diseases such as lung disease, emphysema, and chronic bronchitis.2
  • Pesticides. Pesticides may be used to increase crop yield, especially with indoor-grown cannabis. Control guidelines that regulate the use of pesticides on other botanicals don’t exist for the growing of cannabis.2
  • Mold and fungus. Since marijuana is a live, cultivated botanical, it may be susceptible to contaminated microorganisms—such as aspergillus flavus—which, in some cases, has been associated with health issues, including pulmonary infections or fungal hypersensitivity reactions.2
  • Synthetic cannabinoids. A recent study tested over 1,000 herbal, resin, and e-liquid forms of marijuana samples and found that 24% of the samples contained the synthetic cannabinoid MDMB-4en-PINACA.13 Synthetic cannabinoids can cause severe intoxication and other adverse effects, including psychosis, seizures, respiratory failure, altered brain function, pancreatitis, kidney injury, and death.14

Adulterants in Counterfeit Prescription Medications

Individuals who misuse prescription opioid medications, such as oxycodone (Oxycontin or Percocet), hydrocodone (Vicodin), and alprazolam (Xanax), or stimulants like amphetamines (Adderall) run the risk of ingesting fake pills that may contain fentanyl or methamphetamine.15

Both fentanyl and methamphetamine can be lethal adulterants, especially when someone unknowingly takes them.15

Getting Help for Substance Misuse

If you or a loved one buy substances on the street, it’s important to know that not every drug is what it seems. While tests don’t exist for every contaminant, there are strips to test for fentanyl-laced substances. As previously mentioned, rapid fentanyl test strips (FTS) detect the presence of fentanyl in illicit substances and can help you make an informed decision before using them.7

The safest way to prevent unintentionally ingesting a dangerous adulterant is to stop misusing substances. If you or your loved one is ready to stop substance misuse, treatment options are available. Contact American Addiction Centers (AAC) at

Speak to one of our compassionate and knowledgeable Admission Navigators about your options. They can answer questions about insurance coverage, levels of care, and more, allowing you to start your journey to recovery today.

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