What is Insulin?
Insulin is a hormone that plays a crucial role in regulating glucose metabolism in the body. It comprises 51 amino acids and is structurally organised as a hexamer comprising three heterodimers [1]. The pancreas produces this hormone, specifically its beta cells [2].
Insulin's primary function is to regulate the amount of glucose in your bloodstream. It helps store glucose in your liver and controls how your body metabolises carbohydrates, proteins, and fats [3]. When you consume food, the carbohydrates are broken down into glucose. The pancreas then releases insulin, which transports the glucose in your blood to the cells in your body. The glucose is either used as energy by those cells or stored in your liver as glycogen for later use [3].
Uses of insulin
Treating Diabetes: One of the primary uses of insulin is in the treatment of diabetes. In type 1 diabetes, the body doesn't produce insulin, so insulin injections replace the body's natural insulin [4, 5, 6, 7, 8]. In type 2 diabetes, insulin may be used as a supplement when lifestyle changes and oral medication aren't enough to control blood glucose levels [4, 5, 6, 7, 8].
Tissue repair: Beyond diabetes, insulin has been found to have several other potential applications. It has been used in wound healing, suggesting it may play a role in tissue repair and regeneration [9]. It's also been used in parenteral nutrition, providing essential nutrients directly into the bloodstream [9].
Cardiology: In the field of cardiology, insulin has been used for cardioprotection in acute coronary syndromes, helping to protect the heart during these critical events [9]. It's also been used in an insulin tolerance test to assess the functioning of the hypothalamic-pituitary-adrenal axis, a complex set of interactions among three endocrine glands [9].
Bodybuilding: In the realm of bodybuilding and anti-ageing, insulin has been used due to its anabolic effects, promoting the growth and repair of tissues [9].
Oncology: Insulin has been explored for its potential use in cancer treatment [9]. It's also been used in organ preservation, helping to maintain the health of organs outside the body [9].
Critical illnesses: In critical care, insulin has been used in the management of septic shock, calcium channel, β-blocker overdose, and other critical illnesses in intensive care units [9].
Side effects of insulin
One of the most common side effects of insulin is hypoglycemia or low blood sugar. This can cause dizziness, chills, blurred vision, weakness, headache, and fainting [10].
Weight gain is another common side effect associated with insulin use. This occurs due to better glycemic control, prevention and correction of hypoglycemia, and the anabolic effect of insulin [11, 12].
Insulin injections can also cause discomfort at the injection site, including pain, redness, swelling, or itching. In some cases, changes in the feel of your skin, such as skin thickening or a slight depression, can occur [13].
In rare cases, insulin can cause allergic reactions at the injection site, manifesting as rash, hives, or itching all over the body and difficulty breathing or swallowing [14].
Other potential side effects include constipation, vision changes, muscle cramps, abnormal heartbeat, and swelling of the hands, feet, ankles, or lower legs [15].
In some cases, insulin can lead to water retention and oedema, particularly with rapid improvement in glycemic control [16].
It should be noted that these side effects can vary depending on the type of insulin used and individual health factors. If you experience any side effects from taking insulin, it's crucial to let your doctor know so they can help adjust your insulin dose or explore other treatment options.
Can insulin kill a non-diabetic person?
While insulin is used to treat a variety of conditions, it can also be dangerous if misused, especially by non-diabetic individuals.
In non-diabetic individuals, an overdose of insulin can lead to hypoglycemia, a condition characterised by abnormally low blood sugar levels. This can result in symptoms ranging from mild, such as sweating and trembling, to severe, such as unconsciousness and seizures. In extreme cases, if left untreated, severe hypoglycemia can lead to death [17, 18, 19].
Several case studies have reported instances of non-diabetic individuals dying due to insulin overdose. For example, a young female non-diabetic died after self-administration of insulin [18]. Another case reported a fatal outcome following an accidental insulin overdose in a non-diabetic individual [19].
However, it's important to note that not all cases of insulin overdose in non-diabetic individuals result in death. In one case, a non-diabetic patient who intentionally overdosed on insulin experienced only mild symptoms and was discharged 36 hours later [17].
In conclusion, while insulin is a life-saving medication for individuals with diabetes, it can be dangerous and potentially fatal if misused by non-diabetic individuals. Always consult your healthcare provider to devise a treatment plan suitable for you.