How does insulin work? 11

Insulin is a small hormone responsible for reducing blood sugar levels.

For an overall view of how blood glucose is regulated, see my article “How the body regulates blood sugar levels”.  This article is more specifically about the actions of insulin, is a little more technical, and goes into a little more details of how insulin works to bring about a reduction in blood sugar levels.

Summary of how insulin works

Elevated levels of glucose in the blood stimulates cells of the pancreas to increase insulin secretion into the blood.  The insulin circulates the body, and within minutes, stimulates the liver and muscle cells to take up glucose from the blood.  As glucose is removed from the blood, obviously blood levels fall.  As the levels in the blood fall, the secretion of insulin falls to, so less is produced, and less is taken up by the liver and muscle. In this way, the blood glucose level is reduced back to within the normal range.

Let’s take a closer look at what is happening

Blood glucose level is monitored by the beta cells of the pancreas, and when levels rise above about 90 mg/dl, the pancreas begins to secrete an increased amount of insulin.  The higher the sugar levels, the more insulin is released.

The insulin is carried in the blood plasma (which is the term given to the liquid part of the blood and its the plasma that carries the blood cells around) bound to beta-globulin. Globulins are just large proteins found in the blood, and the alpha & beta-globulins carry hormones, lipids, vitamins e.t.c. around the body.

There are “receptor sites” on the cell membranes of liver & muscle cells, and the insulin binds to these receptors.  This causes the cells to become more permeable to glucose, as well as activating some enzyme systems within the cells.  These changes lead to:

  • Increased Glycogenesis – the conversion of glucose to glycogen in liver and muscles.
  • Increased Glucose uptake by the cells.
  • Increased use of glucose for energy rather than fats or other energy stores.
  • Increased production of fats (and fat deposition) from the excess glucose.
  • Decreased Gluconeogenesis – the production of glucose from non-carbohydrate sources.  Gluconeogenesis usually occurs in the hypoglycaemic state, which stimulates the sympathetic nervous system to release adrenaline (which itself stimulates the conversion of stored glycogen into free glucose). In extreme cases of hypoglycaemia, proteins in the body will be broken down and converted to glucose for energy.  Obviously this is a very bad state to be in, as your body can start to eat your own muscle.

A note about synthetic Insulins

If you do any research on the internet, you'll probably hear about Humalog, a synthetic insulin mimic.  It is often called by a number of other names including lispro Humalog insulin.  Interestingly, this mimic is not identical to human insulin.  Scientists found that by swapping a couple of amino acids on the b-chain of the molecule – namely Lysine and Proline (hence the name), they could get the same effect, but because the insulin was absorbed much faster, it acted more quickly offering a range of benefits to diabetics.  Another insulin mimic that works in a similar way to Humalog, is Novolog.

About Andy

Andy writes for a number of health related sites but has always been fascinated by alternative medicine and home remedies. His deep interests in nature and the body's innate ability to heal itself (given the right condition) have lead him to a pivotal time in his life - and so, Holistic Home Fitness was born. While it's relatively new at the moment, Andy wants to build this site into a huge reference site for a more holistic approach to health and fitness.

11 thoughts on “How does insulin work?

  • Terry


    In your article above, you note that insulin in the blood stream can cause:

    “Increased production of fats (and fat deposition) from the excess glucose.”

    I have three question:

    1) What kind of ‘fat deposits’ are they ?
    2) Where is this ‘fat’ stored in the short term ?
    3) Where is this ‘fat’ stored in the long term ?



  • prasad

    what is the role of vanidium in metabolism of insulin
    and also there r other elements also involed in insulin metabolism
    if u know please send on above adress

    • Andy Post author

      Do you mean vanadium? If so, search google for vanadium insulin and you’ll find quite a bit about it.

  • nermin

    my daughter diagnosied with diabetes since 2007. i can,t adjust her blood sugar level.i want to know how can i calculate the kalories she needs to give her the enough amount of the insulin.

    • Andy Post author

      YOu need to consult your doctor for advise. Not doing so would be extremely dangerous.

  • Rhama lee

    Im a diabetic and has been for years. I am now overweight. My question is, if I lose weight will my diabetesinprove??

  • Nick D

    Rhama Lee… First and foremost, in order to answer that question you have to know which type of diabetes you have. In general if you are diagnosed with Type 2 diabetes because of being obese or overweight, exercise, watching what you eat ( bye bye to simple carbs and hello to complex carbs) , and losing weight can all improve your glucose control. Losing weight has a number of benefits for a diabetic. The leaner you are, the higher your insulin sensitivity (you need less insulin). This means you are losing fat though and not losing muscle. Be sure to be eating the right foods in order to do this. Again, watching the diet will help you here. In short, yes it will help your control. If you lose enough weight you can possibly, but not guaranteed, reverse the diabetes all together if you are Type II. However, if you are Type I, you a out of luck (as in my case). No matter how much exercise or dieting or weight loss you achieve, there is no easy fix, the disease will always remain. Although all of the above does SIGNIFICANTLY improve glucose control. I have been diabetic for over 15 years and monitor my stuff like its my job, because quite frankly it is. With exercise and good dieting I maintain a HA1C under 6.0 consistently. My last H1AC was a 5.3. If you don’t know what the H1AC is and you are diabetic you should ask your doctor to test your H1AC, it is a test for proteins in your blood that gives a 90 day average of your glucose levels. Anything above 5.5 is considered in the diabetic range, although in my case being 5.3 I am still sadly diabetic, just in the non-diabetic range. a 5.5 is an average of ~ 100. The diabetic association recommends an H1AC of under 7.0 or 7.5 I forget to delay the onset of the long-term side effects of diabetes. Kidney disease(dialysis possibly), heart problems, if you are a male erectile dysfunction, nerve damage, vision loss. To name a few! So Rhama, take care of yourself because trust me you don’t want to deal with any one of these problems in life if they are preventable.

  • Larry S.

    I have a question… I just had an insulin test to determine if I was actually producing insulin. It turns out the a normal insulin level in humans is 29, and mine was at 49. Meds are not controlling my sugar level, and the next step is insulin. My question is, if I have insulin resistance syndrome, and am producing tons of insulin that my body cannot recognise, how is giving me more insulin going to help since my body won’t recognise that either? Or will it? IF so, how? and why not my own?

  • Brian willetts

    Nick, i have just read yo reply to Rhama and found it quite interesting. I am a type 1 diabetic, and am desperatly trying to get my hba1c down. i cant seem to get it below 10. I am aware that leval like this, my long term health is at risk.
    I know carb watching and exercise is the way to go, but i already do this.
    At my diabetic clinic, they are great people, but they dont live it. Can i please ask you for advice on how you manage yours?? any type of carbs you avoid,
    I am on insuline pump, not over weight and very active.


  • Salil Save

    I just wanted to know, apart from sugar management, what other tasks , performed by insulin.

  • Maria Fernandez

    Are any studies done on how all the pesticides,chemicals,additives,artificial flavors,artificial colors,artificial preservatives, contribute to diabetes type 2 and even type 1 ? I believe that type 1 diabetes begins with the mothers diet and the use of the above foods that we call enhance or alter by man.? Before pregnancy that is. also what we treat the drinkable water and human food .

    Thank you for your response.

    Maria Fernandez

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