Over the past couple of years, several studies have debated which substances should be labeled as the most addictive. As a result, researchers created three categories: dependence, physical harm, and social harm. Researchers used the data gathered from the dependence category to identify some of the most addictive substances on earth. Nearly 40 million Americans aged 12 years and older are currently using some harmful and addictive substances. 

So, what are the 5 most physically addictive substances? 

Researchers used the data gathered from the dependence category to identify some of the most addictive substances on earth. Learn more here.

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On the Nutt’s scale, heroin scored three out of three, making it the most addictive substance on earth. It is formed from morphine, extracted from the opium poppy plant’s seed pods. These plants typically grow in Southwest Mexico, Columbia, and Asia. It usually appears as a brown or white powder or a black sticky substance popularly known as black tar heroin. 

People addicted to heroin resort to either injecting, smoking, sniffing, or snorting the substance. Others might even practice speedballing, which involves mixing heroin with crack cocaine. When consumed, heroin quickly enters a person’s brain, causing a short-term state of euphoria. There are other effects such as nausea and vomiting, dry mouth, hot flushes, and even severe itching. When used over a long period, users may develop severe conditions like insomnia, liver and kidney disease, lung complications, sexual dysfunction, and damaged nasal tissue (for those who sniff or snort the substance). 

Between 1999 to 2019, nearly 130,000 people died from heroin-related overdoses. When someone overdoses on heroin, their breathing slows, and the lack of oxygen to the brain leads to a condition called hypoxia. Hypoxia has serious mental and nervous system effects, including permanent brain damage. 


Unlike heroin, alcohol is a legally controlled substance that, when consumed, can lower a person’s inhibitions. Ethanol is the ingredient responsible for causing intoxication. It is fine to consume moderately, and not everyone who drinks is an alcoholic. However, when people have no control over their drinking, they have likely developed an alcohol addiction. Over 14 million adults suffer from alcohol addiction.

Alcohol is a central nervous system depressant, and it slows down your brain function when consumed. This leads to short-term effects like poor coordination, slurred speech, lowered inhibitions, and memory loss. Long-term use, however, is more severe and life-threatening. These effects include developing liver and heart disease, stomach ulcers, depression, and dementia, among many others.


This popular white powder is a highly addictive stimulant that can either be smoked, injected, or snorted. It is very popular because of the positive temporary effects on people’s moods and energies. Cocaine causes the brain to develop higher dopamine levels, which is a chemical in the brain responsible for pleasure and reward.

It is very difficult to recognize a cocaine addiction, as many people see it as a recreational drug. Despite the awareness of the dangers of this drug, many people are still curious enough to try it. When consumed over a long period, cocaine can cause permanent damage to the brain and nerve cells in the human body. Many cocaine users have a higher risk of dying from a stroke or cardiac arrest. 


The main addictive ingredient of tobacco, nicotine, is one of the most addictive substances in the world. It is capable of causing an adrenaline rush when consumed and, in some situations, can increase dopamine levels in your brain. Most people use tobacco either by chewing it or, even more popularly, by smoking cigarettes. In the US alone, cigarette smoking is responsible for about every 1 in 5 deaths. Many people attempt to stop using tobacco quickly but end up going back. This is because constant use of tobacco changes your body. 

If a person cannot stop smoking or develops withdrawal symptoms when they try to quit, it’s one of the major signs of addiction. There are several treatment options available for tobacco addiction. However, it can be difficult partly because tobacco products are legal and widely available. 


Also popularly known as barbs, nembies, or blue bullets, barbiturates were initially used to treat insomnia and reduce anxiety. Barbiturates usually come in pill form but can also be used in liquid form. 

Barbiturates cause mild states of euphoria and sleepiness when taken moderately. However, higher doses can be fatal as they can suppress breathing. If not treated immediately, constant usage of barbiturates can lead to circulatory failure, hypothermia, and eventually death. 

Getting Help

The Robert Alexander Center for Recovery is dedicated to helping people suffering from substance abuse and helping them on the road to long-term recovery. We offer a wide range of treatment services, from an intensive outpatient program to a detoxification program for those struggling with substance abuse and addiction. Check out our website for more information: https://robertalexandercenter.com.

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