What is insulin misuse?

In one line

Insulin misuse is when people without diabetes use insulin, a diabetes medicine, without a prescription to build muscle.

What is insulin misuse?
Why does a diabetes drug come up in muscle talk?
Insulin is well known as a medicine for diabetes. Yet among people trying to build muscle, some inject insulin even though they do not have diabetes. What is insulin misuse, and why is it dangerous?
In short
People without diabetes using it for muscle
Insulin misuse means people without diabetes using insulin, a diabetes medicine, without a prescription to build muscle. 'Misuse' means using a drug the wrong way or using too much of it. The biggest danger is that sugar in the blood drops to a dangerous level.
What is blood sugar?
The body's fuel, dissolved in the blood
A sugar called 'glucose', which we get from food, dissolves in the blood and travels around the body. The amount of glucose in the blood is called 'blood sugar'. Glucose is the body's main energy source, and the brain cannot work properly when it runs short.
What is insulin?
A hormone that lets glucose into cells
Insulin is a hormone made by an organ called the 'pancreas'. A hormone is a substance that travels through the blood and sends a signal somewhere else. When blood sugar rises after a meal, insulin is released and lets glucose into cells, and as a result blood sugar goes down.
Diabetes and insulin medicine
Replacing missing insulin to lower blood sugar
Diabetes is a disease in which blood sugar is too high because insulin is lacking or does not work properly. In diabetes where the body makes almost no insulin, insulin is given as a medicine to lower blood sugar. People with diabetes who use insulin often have blood sugar that drops too low.
Why it comes up in muscle talk
It pushes building blocks into muscle and builds more protein
Insulin moves not only glucose but also 'amino acids', the building blocks of protein, into muscle. It also increases the making of new muscle protein, called 'synthesis'. That is why people trying to build muscle use insulin without a prescription.
It also stores fat
It does not go only to muscle
Insulin also speeds up turning extra energy into stored fat, and it blocks the body from taking stored fat out to use. So when people using insulin gain weight, they gain fat along with it.
The biggest danger
Blood sugar that drops too low: 'hypoglycemia'
When blood sugar falls too low, it is called 'hypoglycemia'. At first a person feels shaky, sweaty, hungry and dizzy. Severe hypoglycemia causes passing out or seizures, and can lead to coma or death.
What actually happened
More than half of users had hypoglycemia
When people without diabetes who used insulin to build muscle answered an online survey, more than half had experienced hypoglycemia, and one had passed out. There is also a reported case of a man brought to the emergency room in a coma from unexplained hypoglycemia, who turned out to be secretly injecting insulin.
Common misconception
It is a hormone the body makes anyway, so is it safe?
No. Everyone's body makes insulin, but adding more from outside makes blood sugar drop sharply even in people without diabetes. In that survey, more than half of people who used insulin to build muscle had hypoglycemia, and severe hypoglycemia is life-threatening.
Summary
A dangerous misuse of a diabetes drug for muscle
Insulin misuse is when people without diabetes use insulin, a diabetes medicine, without a prescription to build muscle. Even though the body makes this hormone itself, adding more from outside lowers blood sugar, and severe hypoglycemia is life-threatening. Related terms: insulin, blood sugar, hypoglycemia.