So I realise that prior to my recent comeback to this site I was absent for a very long time and hence haven't posted any real detailed info on compounds/peptides/cycles etc. other than answering questions in various threads here and there.

Many of you probably don't know me, but I'm happy to see that a couple old-timers are still hanging around (shout-out to great guys like tread, viking, bodybuilder etc).

Today I would like to post some detailed info on insulin, as there seems to be a real shortage of that on here.

First off I would like to say that you should not fuck around with substances that can actually kill you (insulin, DNP etc) unless you really know what your doing. But let's cut to the chase:

What is insulin?

Insulin is a polypeptide hormone that is exclusively produced by the pancreatic beta cells. These beta cells are located in clusters known as the "islets of Langerhans" within the pancreas. Insulin's main function within the body is nutrient distribution; as you consume food, the pancreas secretes the stored insulin, which in turn transports the nutrients within your circulatory system to the various destinations such as liver, muscles, fat tissue and brain. Insulin thereby lowers blood sugar levels.

A lack of insulin within the body leads to the sugar disease called diabetes mellitus, the most common metabolic disease. People with this disease have a pancreas that is unable to produce sufficient amounts of the hormone independently, hence warranting an exogenous input and making daily insulin injections necessary.

Insulin and bodybuilding

So why is insulin important in bodybuilding? Insulin itself, if administered alone, does not have a great muscle-building effect. However, it can be seen as an "activator" that greatly enhances the muscle-building effects of anabolic steroids, IGF-1 and growth hormone especially. Within the scientific literature you will find a multitude of studies that clearly document how a combined usage of insulin and growth hormone has a much stronger effect than if you would take these compounds separately. Both insulin and growth hormone increase the protein content within the muscle tissue, and only a combined use will lead to a maximum effect.

As we know, the majority of the growth hormone is channelled into the liver after an injection. It is now the task of these liver cells to begin the production of IGF-1. For this process, not only testosterone and thyroid hormones are needed, but also insulin in a sufficiently high quantity. This however is where most GH users have the big issue: a healthy adult produces about 50 I.E (or 2mg) of insulin per day, and this is not sufficient to guarantee maximum stimulation of IGF-1 production within the liver.

Now the body knows this problem, and hence increases insulin production with the use of GH; it has the ability to induce an increased insulin release from the pancreas. Blood insulin levels rise and the liver can use this to produce IGF-1. The problem is though, that continuous use of GH actually damages the beta cells in the islets of Langerhans and the previously increased insulin production is brought to a halt. This also implies that extensive GH use over long periods of time at high dosages can actually cause a worryingly low endogenous insulin production. Obviously this will cause a reduction in IGF-1 production within the liver. Furthermore, scientific studies have proven that an insulin deficit causes a reduction of GH receptors within the liver, which means that the liver will not be able to utilise some of the injected GH.

This means that if you ensure a sufficiently high insulin level during a GH cycle you are right on the money, as the most important thing is to give the liver the ability to produce the maximum amount of IGF-1. The same holds true for the muscle cells, which are also able to produce IGF-1 locally from testosterone, thyroid hormone, growth hormone and insulin.

On top of that, insulin is also able to improve the anabolic effect of the IGF-1 the body produces; it positively regulates the synthesis and serum concentration of the IGF-1-binding proteins. Additionally, it supports the formation of the important IGF-1/IGFBP-3 complex within the blood. IGFBP-3 is a binding protein that binds with the IGF-1 in the blood and hence protects against breakdown. Hence we can construct the following chain of reference: insulin stimulates the the IGF-1/IGFBP-3 complex, IGFBP-3 lengthens the shelf life of IGF-1 in the blood, which in turn increases the effectiveness of IGF-1.

Finally, insulin increases the amount of GH receptors in the liver and thereby allows the processing of higher GH dosages. Studies have shown that the excretion of GH within the urin is significantly lower if insulin is applied.

Synergystic effect of GH and insulin

Insulin and GH both act in synergy regarding the protein metabolism: both hormones enhance the penetration of amino acids into the muscle cells; this is based on the fact that the permeability of the cell membrane is elevated. within the muscle cell itself both insulin and GH stimulate protein synthesis.

If we compare the effect of GH and insulin more closely, we find another impressive similarity: both hormones promote the conservation of protein. Insulin does this at the expense of glucose, whereas GH does this at the expense of fatty acids. To put it into bodybuilding jargon: we have an anticatabolic effect.

Insulin and GH both protect the athlete in "stress" situations (overtraining) and malnutrition (competition diet) from losing muscle tissue. The reason for this is that both compounds inhibit a process called "gluconeogenesis". Gluconeogenesis is an energy generation process that is carried out within the liver and uses protein as fuel. Since insulin (through the supply of glucose) and GH (through the supply of fatty acids) inhibit gluconeogenesis in different ways, both complement their efficiency with combined use leading to a greater anticatabolic effect.

The disregard for insulin

So based on these facts, why is it that bodybuilders are still sceptical of this compound? For hardcore-bodybuilders, it simply can't be the inherent health risks or fear of side effects.

Actually, this can be based on the antipolytic properties that insulin has: it has the dubious reputation to promote the storage of fat. This is a correct assessment, as we know that insulin increases the uptake of glucose in the fat cells and furthermore also inhibits the secretion of fatty acids out of the fat cell.

Strangely enough though, pro-bodybuilders utilise insulin even during their pre-contest diets. The GH is what plays the crucial role here, as it has an antagonistic effect to the insulin regarding the carbohydrate and fat metabolism. This basically means that GH inhibits the effect of insulin on the fat tissue. The fat cells develop a resistance to insulin, meaning that it can no longer dock on to the fat cell in order to infiltrate glucose molecules. In addition, the GH inactivates a genetic codex named "Glut-4" that causes the transport of glucose into the fat cells. Furthermore, the GH inhibits the anitpolytic effect of insulin (fat loss inhibition) which can be proven by a high amount of free fatty acid circulation in the blood during the combined use of both compounds. Basically, both compounds fight for the upper hand within the fat cell: GH wins.

You will not find a pro bodybuilder that utilises insulin without combining it with GH.

Since I am running out of time I will need to continue this at a later date. I have significantly more info, including dosages etc. Stay tuned.

If a mod could make my headings bold or tell me how to do it that would be greatly appreciated.