Long-term heroin use is linked to a wide range of serious health issues, from brain damage and heart infections to kidney disease, collapsed veins, and a sharply increased risk of deadly infections like HIV and hepatitis C. These problems affect nearly every organ system in the body, and many of them develop gradually, compounding over years of use.
Brain and White Matter Damage
Heroin causes structural changes in the brain over time. Studies have found deterioration of the brain’s white matter, the tissue that connects different brain regions and allows them to communicate. This damage impairs decision-making, makes it harder to regulate behavior, and disrupts how the brain responds to stress. These aren’t subtle effects. They can make it progressively more difficult for a person to control impulses, weigh consequences, or cope with everyday pressures, all of which feed back into the cycle of addiction.
Heart Valve Infections
One of the most dangerous cardiovascular complications is infective endocarditis, an infection of the heart’s inner lining and valves. When heroin is injected, tiny particles from the drug mixture travel through the bloodstream and slam into the heart valves. The tricuspid valve, on the right side of the heart, takes the heaviest hit because it’s the first valve to filter injected material. These particles cause physical damage to the valve surface, creating spots where bacteria can latch on and multiply.
The drug itself also contributes by damaging the inner lining of blood vessels, triggering blood clots, and impairing the immune cells that would normally fight off infection at those sites. Staphylococcus aureus is the culprit in 50 to 60 percent of tricuspid valve infections among people who inject drugs. About 75 percent of those who develop endocarditis from this bacterium had no pre-existing heart defect. The infection created the problem from scratch.
Kidney Disease
Kidney damage is common among long-term heroin users and takes several forms. The most frequently seen is a type of scarring called focal segmental glomerulosclerosis, where the tiny filtering units of the kidney harden and stop working properly. This leads to protein leaking into the urine, high blood pressure, and progressive kidney failure. Patients with heroin use histories ranging from a few months to 15 years have been reported to develop these problems.
A heroin overdose can also trigger a condition called rhabdomyolysis, where muscle tissue breaks down rapidly and floods the kidneys with a protein called myoglobin. This can cause acute kidney failure. Other kidney complications include inflammation of the kidney’s filtering membranes and amyloidosis, a condition where abnormal proteins build up in kidney tissue.
Collapsed Veins and Skin Infections
The loss of functioning veins, known as venous sclerosis, is one of the most visible and persistent consequences for long-term injectors. Repeated injections scar the vein walls, eventually causing veins to collapse and become unusable. This forces people to inject into increasingly risky locations, including the large veins in the groin and neck, which raises the risk of deep vein thrombosis and life-threatening infections.
As peripheral veins fail, each injection session may require multiple attempts, and “missed shots” that deposit the drug into surrounding tissue become more common. This leads to abscesses, cellulitis, and other soft tissue infections that are among the most frequent reasons for emergency department visits and hospitalizations. In severe cases, these infections can require skin grafting or even limb amputation. Swollen hands and legs from blocked lymphatic drainage are also common in people with advanced vein damage.
Lung Complications
Heroin slows breathing. That’s the mechanism behind most overdose deaths, but even at sub-lethal levels, chronically depressed respiration creates conditions for lung infections. Pneumonia and tuberculosis are both more common in long-term users, driven by both the drug’s direct effect on breathing and the general decline in health, nutrition, and immune function that accompanies addiction.
HIV and Hepatitis C
Sharing needles and injection equipment spreads bloodborne viruses efficiently. A 2018 surveillance study across 10 U.S. cities found that 44.2 percent of people who inject drugs had a current hepatitis C infection, with 40.3 percent classified as chronic. Four percent had both HIV and hepatitis C simultaneously. These rates are staggering compared to the general population and reflect how quickly these viruses circulate in communities where injection equipment is shared.
Venous sclerosis actually compounds this risk. When people can no longer use smaller arm veins, they shift to femoral or jugular injection sites where accidental exposure to another person’s blood becomes more likely, and where infections are harder to treat.
Hormonal and Sexual Dysfunction
Long-term opioid use suppresses a key reproductive hormone called luteinizing hormone. This triggers a cascade: testosterone and estrogen levels drop, while a protein that binds to sex hormones increases. The result is a condition called opioid-induced hypogonadism, which affects both men and women. In men, it typically shows up as erectile dysfunction and low sex drive. In women, it disrupts menstrual cycles, causing periods to become irregular or stop entirely. Both sexes can experience infertility and bone loss.
Severe Dental Decay
Heroin dries out the mouth by reducing saliva production. Saliva is one of the body’s primary defenses against tooth decay and gum disease, so without it, bacteria thrive. Long-term users consistently show high rates of decayed, missing, and filled teeth, along with heavy plaque buildup and gum disease. But dry mouth is only part of the problem. Chronic malnutrition, impaired coordination that makes brushing difficult, and the emotional and physical grip of addiction that pushes oral hygiene to the bottom of anyone’s priority list all contribute. The combination creates rapid, severe dental deterioration that often requires extensive treatment.
What Kills Long-Term Users
A 27-year follow-up study tracked causes of death among heroin users and found that overdose, while prominent, is far from the only killer. Among the deaths recorded, HIV/AIDS was the single most common cause, followed by traumatic injuries, drug poisoning, cardiovascular disease, cancer, respiratory infections, and liver disease. This spread of causes reflects how heroin erodes the body on multiple fronts simultaneously. Long-term users don’t face a single health threat; they face a convergence of them, each made worse by the others.