I usually just lurk on this board, but this topic is one I feel I need to add my two cents worth. For those of you who don't know me (many of you do) I've been insulin dependant diabetic going on 20 years now. I am also a medical professional with a background in both human and veterinary medicine (I'm a veterinarian).
I'm on a 'floating scale" where I take a minimum of 2 and up to 5 insulin injections per day of a combination of Regular or regular and NPH insulin (the two baseline injections). As someone who needs this hormone to survive, I'll be the first to admit that this new insulin craze scares the s**t out of me. I've seen diabetics have seizures and end up in a nearly comatose state from taking too much insulin. I've had episodes where my blood sugar has dropped and I've lost all self control (its happened less than a dozen times in the last 19 years, but that doesn't make it any less frightening) I have a friend who threw his mother through a wall when his blood sugar was low. I went after one of my teachers who got in my face and ultimately was suspended when I was a junior in high school.
Now, I've heard non diabetic insulin users scoff and say I don't know what I'm talking about when I say this, the worst thing that will happen is you will become weak and shaky. THEY ARE WRONG. I know of one amateur bodybuilder who ended up in the hospital because of hypoglycemia. I'm going to try to summarize what insulin does, its negative effects, and my thoughts on nondiabetics using this hormone. I'll try to keep things simple, so if something is too "doctorish" please ask and I'll try to rephrase things.
So just what is insulin? Here is a good description taken from another BB board:
insulin is not an androgen, or a steroid for that matter. Insulin is a proteinaceous hormone that is secreted from the pancreas, mostly in response to high sugar levels. It's a polypeptide made from 51 amino acids, separated in an A and B chain by a sulfide bridge (Covalent bond). Its main use is to regulate blood sugar levels. If blood sugar levels are too high insulin is released.
Insulin, in essence facilitates the transport of glucose from the blood stream into the cell. By doing this it maximizes the uptake of nutrients by the cells. This means insulin supports cellular growth, whether it be muscle or fat tissue, especially subcutaneous fat. If you know any insulin dependent diabetics, almost all of them have a "smooth" appearance, even if they are very athletic. This is one of the side effects of taking the hormone they must take to survive. I know some people have suggested I'm a 280+lb guy because of the insulin I take every day. My response is, if I didn't take that insulin, I'd be dead so it doesn't really matter.
So what happens when a diabetic takes insulin? The hormone is slowly absorbed from the subcutaneous space over several hours (regular insulin has an onset time of about half an hour, a peak of about 4 hours, and maximum efficacy of about 8 hours--no obviously this varies somewhat from person to person). The new insulin Humalog has a much faster onset of action and shorter length of duration. Intermediate (NPH) and long acting insulins (Lente) have a much slower onset of action, but continue to work for extended periods of time--up to 24 hours or longer. Blood glucose control for a diabetic is a very careful balance between adequate exogenous insulin (remember their body is no longer producing that hormone), adequate but not excessive carbohydrates, and exercise. The problem with simple sugars, such as candy for a diabetic is the simple fact that the sugar from the food is absorbed faster than the insulin can work. This leads to hyperglycemia and associated complications. In contrast, the diabetics with the "best" blood glucose control also have periods of low blood sugar (less than 60 mg/dl---sorry I'm not converting to mmol/L for the Canadians and Europeans )
So what happens with a non-diabetic who takes insulin? Its essentially the same thing that happens to a diabetic who has an "insulin reaction". Their blood glucose levels will drop. At a certain point, which varies from individual to individual, the body begins to show signs of hypoglycemia. This can vary significantly, I've been in the middle of a surgery with my blood glucose at 35 mg/dl and able to function normally (obviously I scrubbed out and treated myself, but it has happened), yet I know other diabetics who would be unconscious at that level. Generally speaking the more glycogen stores and better shape an individual is in, the better they are able to tolerate low blood glucose. Now, that doesn't change the damage that happens, its just an observation.
As the blood glucose levels drop, the body begins to respond to the lower levels. Adrenalin is secreted. This causes the "shaky, weak feeling" that is commonly described. In addition to adrenalin, glucagon, a hormone secreted from the Alpha cells of the pancreas is secreted. In essence, glucagon has the opposite effect of insulin. It promotes an increase of glucose blood glucose by promoting the breakdown and release of glycogen. Finally, depending on the degree of decrease of blood glucose levels, the body can also have a surge of cortisol released from the adrenal glands. Cortisol also acts to increase blood glucose levels and has an inhibitory effect on insulin. If the exogenous insulin is sufficient that the body is unable to compensate--ie the adrenalin, glucagon, and cortisol is insufficient to raise blood glucose levels, then dire consequences can occur. The goal of the body during hypoglycemia is to maintain the minimum blood glucose level for brain function. If this level is not maintained, loss of brain function, including loss of consciousness, seizures, and even permanent brain damage can occur. I know of one diabetic kid who tried to kill himself by overdosing on insulin. He is permanently brain damaged from this. Considering I've read recommendations of huge doses up to 80 U of regular insulin twice per day for nondiabetics on some bodybuilding boards, I think this may be a very real possibility and am surprised we are not hearing about more idiots ending up in the hospital or dead.
Obviously, this is a pretty significant chain of hormonal events that occurs when the blood sugar levels drop. This chain of events leads to exhaustion, headaches, and loss of athletic ability once the blood glucose levels return to normal and the body tries to replenish lost stores. This time period is also when the "postive" effects occur, in that muscle cells have optimal uptake of nutrients, thus increasing growth potential. I know I cannot have a maximal effort in the squat, bench, or dead lift within about 6 hours of an insulin reaction. My muscles simply do not work at full effectively. There can also be significant loss of fluid from profuse sweating, which means dehydration, which also contributes to decreased athletic performance.
So what about the recommendations of taking dextrose with insulin post workout? Physiologically this doesn't make sense to me. When an individual consumes dextrose the dextrose will be absorbed in a matter of minutes. If an individual consumes the dextrose at the same time as they take the insulin injection, they are going to stimulate an endogenous insulin release. This means their natural occurring insulin levels will be high AND they are going to have circulating exogenous insulin levels. This is going to significantly increase the risk of the development of hypoglycemia.
It also isn't as easy as taking the dextrose a later date because the Regular insulin doesn't peak for a minimum of a couple of hours post injection. If they wait until the insulin peaks, they will have high circulating insulin levels which will simply mean the endogenous excretion will be less.
So how do professional bodybuilders and heavy steroid users get by with taking insulin? First off, anabolic steroids affect how insulin functions in the body. At pharmacological doses, anabolic steroids actually increase insulin's effectiveness and may lead to decreased need of insulin by diabetics. That said, at some of the mega doses advocated by steroid "guru's" now days, there is a negative feedback mechanism (this is especially true with testosterone) which may result in increased insulin requirements. In a nondiabetic, this means they will have higher circulating endogenous insulin levels.
The other big factor is the use of GH. GH will decrease the effectiveness of insulin, and may actually promote the development of diabetes in susceptible individuals. This means decreased insulin effectiveness and possibly lower circulating insulin levels.
The bottom line with this hormone is that there is a very real risk for severe negative effects far outweigh any positive effects. I think there is some value for manipulating endogenous insulin by consuming a simple carbohydrate post workout. This will facilitate glycogen storage and uptake of nutrients by the muscles at a critical time for recovery. I think if you are injecting insulin and are not a diabetic, you are an idiot who is playing with fire.
JK