Insulin 101


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Jun 1, 2010
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Get Shredded!
If you are a seasoned insulin user, this post is going to be WAY too basic to be of value to you. The purpose of this post is to answer the very basic questions for those completely unfamiliar with insulin and its use in the body and for bodybuilding purposes. -RedBaron

There are a lot of posts on forums about insulin and how it is used for bodybuilding purposes. But more basic than this, I am frequently asked....what exactly is insulin and what is it really doing for my body. Here is just a REALLY basic overview of what insulin is in the most basic of terms.

What is Insulin for?
Your body's main source of fuel is a form of sugar called glucose. It gives us energy. After we eat, glucose enters the bloodstream and signals a gland near the stomach, the pancreas, to make insulin.

Insulin is a chemical that helps cells in your body use glucose. Insulin is the storage hormone, glucose disposal chemical, and the main shuttle of glucose into our muscles and other cells. As cells use glucose for energy, the level of glucose in the bloodstream drops. If there is no insulin or the insulin isn't doing its job too much glucose builds up in the bloodstream. This is the condition (hyperglycemia) you find when you have diabetes.

Basic Types of Insulin
There are many different types of prescription insulin. Some are designed to work right away and don't last very long. Other types act more slowly over longer periods of time. Doctors routinely prescribe the type of insulin that matches your body's needs for diabetics. Each case of diabetes is slightly different, and depending on the length of time and severity of the condition, the individual need for insulin and its active window varies greatly. This is why you see so many different brands and types on the market. Depending on the symptoms and condition of the diabetic, the insulin type is tailored to their needs.

Bodybuilding use of Insulin
Now let's cut forward to all of us that are NOT diabetic. Our reason for using insulin is to use its inherent shuttling ability to shuttle nutrients to the muscles. For our purpose we are not trying to achieve long term control of glucose buildup in the bloodstream. We are trying to transport supraphysiological amounts of protein and sugars to the muscles for fuel, repair, and growth. For our purposes, we want to use a quick acting, short lasting insulin. Longer lasting insulin will most likely just equate to added fat ... and not provide any additional positive function. We are using this ONLY as a nutrient shuttle ... which is only needed after we have worked out our muscles and torn them down .... this is when they are screaming out for glycogen and protein.

As we learned above, insulin's purpose is to pull glucose out of the bloodstream and ship it out ... helping cells use it. The problem with this is the brain has a really, really small limited range of blood sugar levels that it will function within. If we put too much sugar into our system uncontrolled by insulin, we check out for good. If we have too much insulin and our blood sugar drops too low, same result....we check out. This is the danger that is inherent in manipulating insulin for our bodybuilding purposes. This is also why the timing of carbs immediately after insulin injections is critical.

What, When, and How?
For the purpose of bodybuilding, we want to use a short acting insulin (such as Humalog, or if not available next best Humulin-R). Either of these should be very inexpensive to purchase (under $40). The dose required will end up being between 4-10 IU's, and even in the most advanced users under 15 IU's should get the job done. For beginners, stay in the 8-10 IU range. The most advantageous time to use this is immediately post workout, when our muscles are screaming out for nutrients and are in a catabolic state. We use a U-100 insulin syringe with 1/2" needle to inject IM immediately post workout. Alternatively, you can inject sub-q if desired. When starting out using insulin, begin with a dose of 2IU's or so, and increase the dose each workout day until you reach your desired maximum.

Immediately following your injection, you will want to do the following religiously:
injection + 5 minutes ??? drink shake with 10g glutamine / 10g creatine / 55g dextrose (based on 7-8 IU's - 7-8 grams per IU more precisely)
Injection + 15 minutes ??? drink shake with 80g of whey protein in water
Injection + 60 ??? 75 minutes ??? eat a protein / carb meal with 40-50g of protein, 40-50g of carbs, NO FATS
Avoid fats for 2-3 hours for Humalog IM, 3-4 hours for Humalog sub-q, 4-5 hours for Humulin-R.

Things to Watch for
Insulin's most commons side effect is HYPOGLYCEMIA (low blood glucose). It is important that you know the signs of hypoglycemia they may occur quickly!
They are:
- Shakiness
- Anxiety
- Fast heart beat
- Hunger
- Sweating
- Blurred vision
- Dizziness
- Weakness
- Headache
- Irritability

If any of these symptoms occur, you should eat some form of quick acting sugar to prevent the symptoms from getting worse (e.g., two or three glucose tablets, one tube of glucose gel, one-half cup of fruit juice or regular soft drink, one tablespoon of honey, or one tablespoon of sugar dissolved in water)

Always have something like the above on hand when using insulin. Hypo symptoms can and will hit hard and fast, and you will have a very small window of time to react. Be ready!!

Well, hopefully you now have a basic understanding of insulin. There are many other in-depth articles and studies available that I would encourage you to read and study, especially before venturing into insulin use. While it is extremely useful for bodybuilding, it is also dangerous enough to not be taken lightly.....know what you are doing and have a plan BEFORE you begin to consider using insulin. As in anything we do, research, research, research!!! Hopefully this post will whet your appetite to look into insulin.....used properly it is definitely one of modern bodybuilding's great tools.


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Jul 18, 2012
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Good info. Not for the faint of heart or the lazy. Laziness with insulin will without a doubt kill you. You have to be on your game