No drug is without side effects, but insulin has the least side effects among current drugs for treating diabetes.

Oral medicines need to be metabolized by the liver and kidneys, which may affect liver and kidney function in the long term. Insulin is a secretion of the human body itself, so there is no risk in this regard.

The only side effect is hypoglycemia, but no matter which method you use, there will be a risk of hypoglycemia; another side effect is that the skin at the injection site may have an allergic reaction, but it is very mild, such as redness and swelling.