what is insulin

What is insulin?

Insulin is a hormone produced by your pancreas that tells your cells to soak up sugar in the blood.  The insulin that you inject into your body is now made by chemists.  By using genetic engineering technology, 95% of insulin made is “human insulin”, though some manufacturers still use pig-derived insulin.

Why should I use insulin?

Diabetes care involves lowering the blood sugar enough so that the chances of developing complications from your diabetes are decreased.  Over time, many diabetics will develop a “resistance” to medications like metformin and glipizide, and it may be necessary to start insulin.  According to the American Diabetic Association guidelines, insulin should be started if your blood sugar goals cannot be achieved after trying 2 oral diabetic meds or if your initial HgA1c is very high.

What are the different types of insulin?ima 2

There are various types of insulin: short acting insulinregular insulin,intermediate-acting insulin and long acting insulin. These different types of insulin are different from one another in that they take different amounts of time to “peak” if you will. The graph above shows the different types of insulin. The short acting insulin being represented by the black line (aspart, lispro, glulisamine), the regular insulin being represented by the blue line. The semi-long acting being represented by the magenta line (NPH), and the long acting insulins being represented by the green line (Detemir) and red line (glargine).

Currently, we think the best way to deliver insulin is to mimic what the body does physiologically; meaning deliver insulin to the body when the body would expect to have insulin (aka. after a large meal). The graph below is meant to represent how this would look like supposing you eat 3 good meals a day.imaa

The grey shaded area represents what your blood sugar does throughout the day.  See how it peaks about 30 min after you eat a meal?  The magenta line represents how your body naturally reacts to you blood sugar levels.

When treating your diabetes, I generally will start with only a long acting insulin if i can get away with it; but i will often have to add a short acting insulin to compensate for those blood sugar spikes after meals.ima 4

In the medical world, we call short acting insulin and regular insulin “prandial” insulin.  Prandial insulin means insulin that we self inject to compensate for meal time elevations of blood sugar.  The goal is to give your self the right amount of insulin so that it’s peak effect occurs 30 minutes after your meal


The above graph is showing glargine, a long acting insulin.  Long acting insulins are used to cover your blood sugar levels throughout the day and night.  Remember, because as a diabetic you are less responsive than normal to the insulin that your pancreas secretes, you constantly have high blood sugar levels.  Long acting insulin can be used once or twice a day.


This graph above us is showing the redheaded step child of insulin; NPH.  NPH is a semi-long acting insulin that peaks after 6 hours and takes a while to level off.

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To make matters more confusing, there are short acting and regular insulins that are in a 70/30 mix.  This is where 70% of the insulin is in a “crystalized” form that stays under the skin and gets slowly released over time.  The other 30% of the insulin is in it’s “liquid” form and acts like normal.  The above graph represents what Humulin(R) 70/30 would look like.  I never liked this graph because it shows the insulin being injected at the same time as dinner. The injection should occur 2-4 hours before dinner time because this is how long it takes regular insulin to peak.

What type of insulin is right for me?

Once I’ve recommended starting insulin to get better control of your diabetes, I try to tailor the different types of insulin based on your life style.  Ideally I would be able to convince you to eat a well balanced diet, lose weight, check your blood sugar levels three times a day, and being able to afford the out-of-pocket expenses for optimal medications.  Unfortunately, this isn’t an ideal world, and life circumstances sometimes makes it difficult to do the above.  I accept that sometimes we have to work within the constraints life gives us.

For this reason, and for me to do the best job i can for you, it’s very important that you are realistic with what you can commit to in caring for yourself.

If you are someone who can commit to eating 3 balanced meals per day and can check your blood sugar regularly without financial constraints then a combination of Lantus (glargine) and Novolog (aspartate) may be ideal for you

If you are the same above person but do have financial constraints then Humulin-N (NPH) twice daily and Humulin-R three times a day may be ideal.

If you are someone who can’t commit to regular blood sugar checks and have sporadic meals, but are without financial constrains, then I may recommend Lantus with Novolog as needed.

If you’re the same person above but have financial constraints then maybe i’ll recommend Humulin-N (NPH) twice daily without prandial insulins.

If you are the type of person that can only commit to insulin injections twice a day, you eat a large breakfast and dinner, and have no financial constraints I may recommend Novlog 70/30.

If you are the same person above but have financial constraints then maybe I’ll recommend Humulin R (Regular insulin) 70/30.


How do I use insulin?

Insulin comes in a liquid form.  It is either in a vial that you have to draw up, or it comes in a pen.

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Insulin that comes in a vial is much cheaper but be warned: math is involved. Insulin comes in units.  In a vial there are 100units for every 1mL.  Insulin syringes are 1mL syringes.  So basically every .10 (tenth) of an mL is the equivalent of 10 units.  To draw up the insulin you first need to clean the top of the vial with an alcohol swab, turn it upside down, and then draw the right amount of insulin into your syringe.ima 8

Insulin that comes in pen form is much more expensive but math is much easier.  Basically the pen has everything you need in it.  It has the insulin, syringe, needle and a nifty pen clip.  The way it works is that you dial in the amount of units you want and then press a button.

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Love handles double as insulin injection sites.  The basic premise to injecting yourself with insulin is finding a love handle, pinching it (who can resist?), inserting the needle so that it’s right underneath the skin, and then injecting the right amount of insulin into the subcutaneous layer as shown below.

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Here’s a nice map of different love handles for injection or recreational purposes.  I recommend switching injection sites on a regular basis.

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How much insulin do I need?

This is a complicated question to answer.  My approach to figuring out how much insulin you need (if I think you need it at all) is based on a number of factors.

One factor I consider is how dangerous insulin will be for you if your blood sugar gets too low (hypoglycemia).

If you are elderly, thin and with a poorly functioning kidney, then I prefer to err on the side of caution and keep you a little sweeter, aka: your average blood sugars will be a bit higher.  I may choose to use a longer acting insulin rather than short insulins because long acting insulins such as Lantus are much less likely to cause hypoglycemia.  If you are young and healthy I may be a little more aggressive and use short-acting insulin in addition to long-acting insulin.

The another factor I consider is what should our HgA1c goal be?  If your organs don’t function very well and you’ve had multiple strokes and heart attacks I may keep you on the sweeter side (higher average blood sugar) and keep your HgA1c around 8% ish.  If you are young and healthy I’ll aim to keep your HgA1c less than 7.

These are just a few of the many factors that I think about before prescribing a dose of insulin.  Typically 1/2 of my total insulin dose will be in basal form and the other 1/2 will be prandial.  For instance if you were to take 60 units of insulin total then I would prescribe 30 units of Lantus at bed time and 10 units of Novolog three times daily before meals (assuming you eat 3 balanced meals a day).

When should I inject my insulin?

Great question! (I actually made this question myself). Allow me to re-introduce the “insulin graph” again.

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Lets go over the different types of insulin individually.

Short acting (Aspartate, Lispro and Glulisiline) – Short acting insulins are prandial insulins meaning that they are meant to curb the meal time sugar spike that occurs 30 minutes after mealtime.  The beauty of these short acting insulins is that they peak after 30 minutes.  This is why I recommend using them just before a meal.

Regular insulin – Regular insulin is also a prandial insulin.  The thing I like about regular insulin is that it’s less expensive than short acting insulins.  The thing I dont like, is that it peaks 2-4 hours after injection.  This means that your meal should be 2-4 hours after injection.  It also means that you better be feeling hungry in 2-4 hours or you’ll pay for it (with hypoglycemia).

NPH – Intermediate insulins are basically the poor man’s basal insulin.  It doesn’t last as long as Lantus or Detemir and it’s peak squirts off more insulin meaning that you are more likely to develop hypoglycemia.  I recommend injecting NPH in the morning 7 hours before when you would eat lunch and then again at lunch time.  The down side to NPH is that when you sleep your blood sugars may be uncontrolled.  But hey, this is better than nothing! Because NPH is crystals of insuin suspended in liquid I recommend shaking it vigorously before drawing it up to get an even amount of crystals into your syringe.

Detemir- Aka Levemir, which is the brand name that is commonly used. This is a long acting insulin that is injected twice a day. It peaks after 12 hours but the peak is so mild that it is uncommon for it to cause low blood sugar (hypoglycemia).

Glargine – Aka Lantus, the brand name commonly used.  This is my favorite basal insulin.  Why? It’s a once a day injection and it covers night time elevated blood sugars.  The down side to Lantus is that it’s expensive.  The best time to inject Lantus is at bed time.  It works differently from the other insulins because when you inject it under your skin it will actually form a crystal which slowly melts over time.  And this steady melting, if you will, releases insulin steadily like your pancreas does naturally.  Sometimes your Lantus dose may be so high that I may ask you to inject it twice a day.  Usually this occurs when you are using more than 60 units of Lantus at once.