Bulimia nervosa causes damage across nearly every system in the body, from the teeth and throat to the heart and reproductive organs. The repeated cycle of binging and purging creates a cascade of physical harm that worsens over time, and some consequences can become life-threatening even when a person’s weight appears normal.
Damage to the Throat, Stomach, and Esophagus
The digestive system takes the most direct hit. Repeated vomiting exposes the esophagus to stomach acid it was never designed to handle, leading to chronic inflammation (esophagitis), painful ulcers, and gastroesophageal reflux disease (GERD). Over time, the force of vomiting can cause tears in the lining of the esophagus, sometimes called Mallory-Weiss tears, which can bleed significantly. In rare but serious cases, the stomach itself can rupture from the strain of repeated binging.
The intestines are affected too. Many people with bulimia develop irritable bowel syndrome, and those who misuse laxatives as a purging method can lose normal bowel function over time. The gut essentially becomes dependent on laxatives to move, making constipation a stubborn problem during recovery.
Tooth Erosion and Swollen Glands
Dentists are sometimes the first to spot signs of bulimia. Stomach acid dissolves tooth enamel in a distinctive pattern: the erosion concentrates on the backs of the teeth, particularly the upper front teeth, because that’s where vomit makes the most contact. Teeth become thin, translucent, brittle, and painfully sensitive. Once enamel is gone, it doesn’t grow back.
The salivary glands, especially the parotid glands along the jawline, often swell noticeably. This happens because the glands enlarge to keep up with the increased demand for saliva production triggered by frequent vomiting. The result is a visibly puffy or rounded appearance in the cheeks and jaw area that can persist for weeks or months even after purging stops.
Heart Rhythm Problems From Electrolyte Loss
This is the most immediately dangerous consequence of bulimia. Vomiting, laxative use, and diuretic misuse all flush potassium, sodium, and other electrolytes out of the body. Potassium is critical for keeping the heart beating in a regular rhythm. When levels drop too low, the electrical signals that coordinate each heartbeat become erratic.
Research on patients with severe potassium depletion (levels below 2.0 milliequivalents per liter, where normal is 3.5 to 5.0) has documented dangerously prolonged heart rhythms and episodes of a chaotic heartbeat pattern called polymorphic ventricular arrhythmia. In one study, about 10% of patients showed severe potassium depletion, and some developed heart rhythm disturbances serious enough to cause sudden cardiac arrest. Notably, when potassium levels were normal, these dangerous rhythm changes did not appear, which underscores how directly the purging behavior drives the cardiac risk.
Over the long term, repeated electrolyte imbalances can weaken the heart muscle itself, eventually contributing to heart failure.
Menstrual and Reproductive Disruption
Even though people with bulimia typically maintain a normal body weight, their reproductive hormones are often significantly disrupted. Studies consistently find that 37 to 64% of women with bulimia experience irregular menstrual cycles, and complete loss of periods occurs in 7 to 40% of patients. Ultrasound studies reveal an even more striking finding: 76 to 100% of women with bulimia show polycystic ovarian changes.
The mechanism appears to work on multiple levels. The chaotic pattern of binging and restricting causes large swings in insulin, which in turn elevates circulating androgen levels, a hormonal pattern associated with polycystic ovary syndrome. At the same time, purging reduces levels of key reproductive hormones like estradiol and disrupts the pulsing release of luteinizing hormone that normally triggers ovulation. Frequent vomiting, low thyroid hormone levels, and low dietary fat intake are all independently linked to irregular periods in bulimia.
Slowed Metabolism and Thyroid Changes
People with bulimia often find that their bodies seem to resist weight loss despite purging, and there’s a metabolic reason for that. Research shows that people with bulimia have diminished caloric requirements and a reduced resting metabolic rate compared to healthy individuals. The binge-purge cycle appears to temporarily boost thyroid hormone levels (which govern how fast the body burns energy), but this creates a misleading picture. When patients stop purging, thyroid hormones like T3 and thyroxine actually decline, and levels of the hormone that stimulates the thyroid (thyrotropin) rise. This suggests the body’s metabolic thermostat has been thrown off, potentially reflecting deeper disruption in the brain’s hormonal control center.
The practical result is that the body becomes increasingly efficient at storing calories and resistant to the very weight control that drives the disorder, creating a frustrating cycle that often intensifies the binge-purge behavior.
Visible Skin and Hand Changes
One of the telltale physical signs of bulimia is Russell’s sign: calluses or scarring on the knuckles of the dominant hand. These form from repeatedly scraping the knuckles against the upper teeth during self-induced vomiting. The skin thickens in response to the friction, and under a microscope, these calluses show overgrowth of the outer skin layer and scarring in the deeper tissue beneath. Russell’s sign is considered the most characteristic external marker of purging behavior.
Other skin changes can include dryness, poor wound healing from malnutrition, and the growth of fine, downy body hair (a response the body mounts to conserve heat when nutritional status declines).
Dehydration, Malnutrition, and Diabetes Risk
Even when someone with bulimia eats large quantities of food during a binge, purging prevents normal absorption of nutrients. Chronic dehydration is common and compounds the electrolyte problems already described. Deficiencies in vitamins, minerals, and essential fatty acids accumulate over time and contribute to fatigue, weakened immunity, poor concentration, and brittle hair and nails.
Bulimia also raises the risk of developing type 2 diabetes. The repeated surges of blood sugar during binges, followed by the metabolic disruption of purging, place ongoing stress on insulin regulation. Combined with the polycystic ovarian changes that affect insulin sensitivity, the metabolic environment becomes increasingly unstable.
Mental Health and Suicide Risk
The physical damage of bulimia doesn’t exist in isolation. The disorder carries an increased risk of suicide, driven by the interplay of depression, shame, impulsivity, and the neurochemical effects of chronic nutritional disruption. Electrolyte imbalances themselves can affect mood and cognitive function, creating a feedback loop where the physical consequences of bulimia worsen the psychological ones. This combination of medical and psychiatric harm is what makes bulimia one of the most dangerous psychiatric conditions by mortality rate.