Insulin injection is in a class of medications called hormones. Insulin injection is used to take the place of insulin that is normally produced by the body. It works by helping move sugar from the blood into other body tissues where it is used for energy. It also stops the liver from producing more sugar.
ADRENALIN :
It is an extremely potent drug and will send your heart into a condition (read failure) within seconds that can cause death.
Adrenaline has strict medical uses in life saving conditions where it is diluted to 10 thousandth parts and injected intracardiac if a person's heart has stopped working. It may it may or may not work. Also it is given in life threatening allergic reactions.
THYROXINE :
Thyroxine is the main hormone secreted into the bloodstream by the thyroid gland. It is the inactive form and most of it is converted to an active form called triiodothyronine by organs such as the liver and kidneys. Thyroid hormones play vital roles in regulating the body’s metabolic rate, heart and digestive functions, muscle control, brain development and maintenance of bones.
Levothyroxine is used to treat hypothyroidism, a condition where the thyroid gland does not produce enough thyroxine. Levothyroxine injection can be used as a substitute for the oral dose when a rapid effect is needed and when the oral route is not allowed .
THUS WE CAN INFER THAT, CERTAIN HORMONES CAN BE SAFELY INJECTED TO OUR BODY ( like insulin or throxine) WHEN RAPID ACTION IS REQUIRED. ON THE OTHERHAND, INJECTING HORMONES LIKE ADRENALIN CAN HAVE SEVERE AFTEREFFECTS AND MUST BE DONE VERY CAREFULLY. IT ALL DEPENDS ON THE SITUATION.