By one of the most rigorous measures available, yes. A landmark study published in The Lancet scored 20 drugs on 16 different harm criteria and found that alcohol was the most harmful drug overall, with a score of 72 out of 100. Heroin came in second at 55. But that ranking depends heavily on how you define “worse,” because the two substances cause damage in very different ways.
How the Harm Rankings Work
In 2010, a panel of drug experts in the UK used a method called multicriteria decision analysis to score drugs on harms to the individual user and harms to others. The categories included things like physical damage, dependence, loss of relationships, injury, crime, economic cost, and community harm. Heroin, crack cocaine, and methamphetamine scored highest for harm to the individual user (34, 37, and 32 points respectively). But alcohol dominated the “harm to others” category with 46 points, far ahead of heroin’s 21. When both dimensions were combined, alcohol’s total of 72 placed it above every other drug studied.
This result shocks people because heroin is so much more dangerous on a per-user basis. The key is scale. Hundreds of millions of people drink alcohol worldwide, while heroin use is comparatively rare. A substance that causes moderate harm to a massive population can generate more total damage than one that devastates a small number of users. That distinction matters for public health policy, but it doesn’t mean a glass of wine is more dangerous to you personally than a dose of heroin.
Overdose Risk for the Individual
When researchers compare how close a typical dose is to a lethal dose, both alcohol and heroin land in the highest risk category. A study published in Scientific Reports calculated that the lethal benchmark dose for heroin is just 2 mg per kilogram of body weight, compared to 531 mg per kilogram for alcohol. That makes heroin far more potent drop for drop, but both substances have dangerously narrow safety margins when consumed at typical recreational levels.
Alcohol’s margin of exposure, the gap between what people actually consume and what could kill them, was the lowest of all substances studied at the population level. Heroin had the second lowest for individual users. In practical terms, this means both drugs sit uncomfortably close to their lethal thresholds compared to substances like cannabis, which has a much wider safety buffer.
Withdrawal: Where Alcohol Is Deadlier
One area where alcohol is unambiguously more dangerous than heroin is withdrawal. Alcohol withdrawal can trigger delirium tremens, a condition involving seizures, hallucinations, and cardiovascular instability that carries a mortality rate of 1% to 5%. Heroin withdrawal, while intensely miserable, with muscle pain, vomiting, insomnia, and severe anxiety, is not life-threatening when it occurs on its own without other medical complications.
This surprises many people who assume heroin withdrawal is the most dangerous kind. In reality, alcohol and benzodiazepines affect the brain’s inhibitory signaling system in a way that, when suddenly removed, can cause fatal overexcitation. Opioid withdrawal works through a different pathway and, despite being an agonizing experience, does not carry the same risk of death.
The Death Toll at a Global Scale
The World Health Organization reported 2.6 million deaths attributable to alcohol in 2019 alone. Of those, roughly 1.6 million were from chronic diseases like heart disease (474,000) and cancer (401,000). Another 724,000 came from injuries, including traffic crashes, self-harm, and interpersonal violence. An additional 284,000 were linked to infectious diseases worsened by drinking.
Global heroin and opioid deaths are harder to isolate from broader drug statistics, but they number in the hundreds of thousands annually rather than millions. Again, the difference is largely about how many people use each substance. Alcohol is legal, socially encouraged, and consumed by billions. Heroin’s user base is a tiny fraction of that. Per user, heroin is far more likely to kill you.
Addiction and Relapse
Both substances are highly addictive, and the relapse numbers are strikingly similar. Within three months of treatment, 40% to 60% of people treated for alcohol problems return to drinking. For heroin, the three-month relapse rate is about 60%. By the 12-month mark, both converge at roughly 70% to 80%. Neither addiction is easy to escape, and the comparable relapse rates reflect how deeply both substances rewire the brain’s reward and stress systems.
Harm to Others and Society
Alcohol’s outsized score on harm to others reflects damage that heroin rarely causes at the same scale. Drunk driving kills tens of thousands of people every year. Alcohol fuels domestic violence, sexual assault, and public disorder in ways that heroin, which tends to sedate users, does not. The economic costs are enormous: a U.S. government analysis estimated alcohol abuse cost $89.5 billion in 1980 dollars (well over $300 billion adjusted for inflation), driven by lost productivity, healthcare, motor vehicle crashes, and crime. Drug abuse collectively cost $46.9 billion, a figure that includes all illicit drugs, not just heroin.
Heroin’s societal harms run through different channels. Injection drug use is a major driver of infectious disease transmission. In one study of heroin and cocaine users, over 50% tested positive for hepatitis C, with injection as the primary risk factor. HIV rates in the same population were around 8.5%. These diseases ripple outward to sexual partners, children, and healthcare systems. Alcohol is also linked to sexually transmitted infections through impaired judgment, but it doesn’t carry the same needle-borne disease burden.
Damage During Pregnancy
Both substances cause serious harm to a developing fetus, but the type of damage differs. Alcohol is a known teratogen, meaning it directly disrupts fetal development. Fetal alcohol syndrome is the leading cause of preventable intellectual disability in the United States, causing permanent changes to brain structure, facial features, and cognitive function. No amount of alcohol has been proven safe during pregnancy.
Heroin exposure during pregnancy leads to different problems: premature birth, restricted growth in the womb, and low birth weight. Babies born to opioid-dependent mothers often develop neonatal abstinence syndrome, essentially going through withdrawal after birth. This is treatable in a hospital setting, and unlike fetal alcohol syndrome, it does not typically cause permanent structural changes to the brain. The long-term developmental outcomes for opioid-exposed children are still being studied, but the evidence so far suggests alcohol causes more lasting prenatal damage.
So Which Is Actually Worse?
The answer depends entirely on the lens. If you’re asking which drug causes more total suffering across the planet, it’s alcohol, and it’s not close. Legal status, widespread availability, and cultural acceptance mean alcohol touches far more lives and destroys far more of them in aggregate. If you’re asking which drug is more dangerous to an individual who uses it, heroin is more acutely lethal per dose, more likely to cause fatal overdose in any given session, and more likely to lead to injection-related diseases.
Alcohol kills more slowly in most cases, through liver disease, cancer, cardiovascular damage, and accumulated injuries. Heroin can kill in a single use if the dose is wrong or contaminated. But alcohol withdrawal can kill in ways heroin withdrawal cannot. And alcohol’s role in violence, accidents, and chronic disease gives it a societal footprint that dwarfs any single illicit drug. The uncomfortable truth the research points to is that the drug causing the most harm worldwide is the one sold in every grocery store.