Injecting insulin when the body does not need it is dangerous because the hormone’s primary function is to rapidly lower blood glucose levels. Insulin, naturally produced by the pancreas, moves glucose from the bloodstream into cells for energy or storage. In a non-diabetic person, this system is finely tuned, and an extra, uncontrolled dose immediately overwhelms the body’s natural balance. The subsequent, swift drop in blood sugar is called hypoglycemia, which can quickly become a life-threatening emergency.
How Insulin Affects Normal Glucose Balance
A healthy person’s pancreas maintains blood glucose within a narrow, safe range, typically between 70 and 100 milligrams per deciliter (mg/dL) while fasting. This balance relies on the interplay between insulin, which lowers blood sugar, and glucagon, which raises it by signaling the liver to release stored glucose. The body’s own insulin production is precisely matched to carbohydrate intake and the body’s energy demands.
When a non-diabetic individual injects exogenous insulin, this precise homeostatic mechanism is disrupted. The injected insulin acts as an excessive signal, forcing glucose out of the bloodstream and into muscle, fat, and liver cells at an uncontrolled rate. This process quickly depletes circulating blood sugar, causing the glucose level to plummet.
In response to falling glucose, the body releases counter-regulatory hormones, such as glucagon and epinephrine (adrenaline). Glucagon instructs the liver to break down stored glycogen (glycogenolysis) and to create new glucose (gluconeogenesis). However, the volume and potency of the injected insulin often overwhelm these natural defenses, leading to a profound state of hypoglycemia the body cannot correct on its own.
Recognizing the Stages of Low Blood Sugar
The symptoms of a blood sugar crash progress in distinct stages, reflecting the brain’s increasing distress as it is starved of fuel. The initial phase is mild or adrenergic hypoglycemia, characterized by the sympathetic nervous system activating its “fight or flight” response. Symptoms are caused by the release of adrenaline and include a rapid heart rate, shakiness, sweating, and intense hunger.
As blood glucose continues to fall, the condition progresses to moderate or neuroglycopenic hypoglycemia, where the brain suffers from glucose deprivation. Symptoms shift from physical signs of adrenaline release to cognitive and behavioral changes. These manifest as confusion, difficulty concentrating, irritability, slurred speech, and poor coordination. During this stage, the person may seem disoriented or acutely intoxicated.
The final and most dangerous stage is severe hypoglycemia, an immediate medical crisis. If the brain is deprived of glucose for too long, life-threatening symptoms emerge, requiring intervention from another person. These symptoms include seizures, loss of consciousness, and a coma, which can lead to permanent brain damage or death if not reversed quickly. This severe state is often referred to as insulin shock.
Emergency Steps and Medical Intervention
Immediate action is mandatory when a non-diabetic person experiences insulin-induced hypoglycemia, as time prevents permanent harm. If the person is conscious and able to swallow, administer a source of fast-acting carbohydrate, aiming for 15 to 20 grams of sugar. This includes half a cup of regular soda, fruit juice, glucose tablets, or a tablespoon of honey.
Following the initial intake of fast-acting sugar, the person should be monitored closely, and blood glucose should be rechecked after 15 to 20 minutes. If symptoms persist or glucose remains dangerously low, the administration of fast-acting sugar should be repeated. Once blood sugar stabilizes, the person should consume a meal containing complex carbohydrates and protein to prevent a subsequent drop.
If the person loses consciousness, becomes unable to swallow, or experiences seizures, emergency medical services must be called immediately. Nothing should be forced into the person’s mouth due to the risk of choking. If a glucagon emergency kit is available and the caregiver is trained, an injection of glucagon can be administered, triggering the liver to release stored glucose.
Upon arrival at the hospital, treatment involves the intravenous (IV) administration of dextrose, a sterile form of glucose. This delivers sugar directly into the bloodstream to rapidly counteract the effects of excessive insulin. Because high doses of exogenous insulin can remain active for many hours, the patient requires continuous monitoring and may need a prolonged IV dextrose infusion until the injected insulin has been fully cleared from the system.