It has become a hot topic as of late when it comes to health and wellness. Podcasts, social media posts, gym talk, conversations at work and amongst friends - insulin is being spoken about more now than ever before. And rightfully so. There is a lot of misunderstanding and confusion around it, so let’s address the basics.

What is insulin?

At its core, insulin is a hormone produced by the pancreas. It is required to sustain life, and without it we simply would not be able to survive. ^[1]

Insulin plays an important role in helping the body absorb, use, and store nutrients. It is most commonly known for its role in helping regulate glucose, or blood sugar. Having a basic understanding of insulin makes it much easier to understand metabolism and metabolic health. ^[1]

What happens after you eat?

After we eat carbohydrates, they are broken down into simple sugars, including glucose, which are absorbed into the bloodstream. Protein can also be converted into glucose when needed, while fat generally does not contribute much to glucose production. ^[1]

That glucose can then be used by cells for energy or stored for later use. In tissues such as skeletal muscle and fat, insulin plays a major role in helping glucose move from the bloodstream into the cell. ^[1,3]

Dr. Benjamin Bikman, a metabolic scientist and researcher, has used the analogy of insulin being like the bouncer or doorman at the front door of a venue. Picture the venue as one of your cells. Glucose is waiting outside, and insulin is the signal that helps get the door opened so glucose can enter. ^[8]

More specifically, insulin binds to receptors on certain cells and sends a signal that helps glucose move into the cell where it can be used or stored. The bouncer analogy is a simplified way to picture the process, and there are tissues and situations where glucose uptake does not depend on insulin in the same way. ^[3,8]

How does insulin manage blood sugar?

It is likely that your understanding of insulin is that it is responsible for managing blood sugar. You would be correct in saying so. So how does insulin do this?

After you eat carbohydrates, glucose enters the bloodstream and blood glucose naturally rises. That rise is normal. In response, specialized cells in the pancreas sense the increase and release insulin into the bloodstream. ^[1]

If you recall the earlier analogy, insulin helps signal certain cells to take up glucose. As glucose moves from the bloodstream into cells where it can be used or stored, blood glucose comes back down toward its normal range. This is one of the major ways insulin helps the body regulate blood sugar after a meal. ^[1,3]

Insulin and storage

Insulin plays a major role in helping glucose enter muscle and fat cells, where it can be used for energy or stored for later use. It is also often described as a storage hormone because it helps signal the body that nutrients are available and can be stored when they are not immediately needed. ^[3]

Your metabolism is such a finely built system. Different processes work hand in hand with one another to make sure fuel is available when the body needs it. Even when there is not much glucose coming in from a recent meal, the body can release stored glucose or make new glucose when necessary, while also relying on other fuel sources such as fat.

Muscles store glucose as glycogen, which is one important source of fuel for muscular activity. It is not the only fuel our muscles can use, but it plays a major role, especially during higher-intensity exercise. ^[4]

The liver also stores glucose as glycogen and can release glucose into the bloodstream when needed. During stress, hormones such as adrenaline and cortisol can help make more fuel available to the body. This is one reason blood glucose can rise even when you have not recently eaten.

Insulin sensitivity vs insulin resistance

Another term drawing a lot of attention is insulin resistance. What exactly is it? Simply put, insulin resistance is a state in which cells become less responsive to insulin’s signal. ^[2]

Going back to the bouncer analogy, picture glucose waiting at the door of the cell. Under healthy conditions, the body may only need a relatively small insulin signal to get the response it needs (the single doorman was sufficient to allow glucose in). As insulin resistance develops, the body may need to release more insulin (multiple doormen) to produce the same effect. The analogy is not literal, but it helps illustrate the basic idea: more insulin is required to get the same job done. ^[2,8]

 

Over time, insulin resistance and chronically elevated insulin can potentially contribute to, or be associated with, issues such as energy fluctuations, fatigue, difficulty managing body weight, and other signs of metabolic dysfunction. Some people may also experience things like brain fog or low energy, although insulin resistance can also develop without obvious symptoms. ^[2]

The goal is to remain insulin sensitive, meaning your cells respond well to insulin and your body can maintain healthy insulin levels and normal blood glucose regulation. Regular exercise, mindful nutrition, adequate sleep, stress management, and evidence-based supplementation can all play a role in supporting healthy glucose metabolism and insulin sensitivity. ^[4-7]

The bigger picture

Understanding insulin gives us a clearer picture of metabolism as a whole. Insulin is not the enemy; the goal is to remain insulin sensitive so the body can function effectively with lower insulin levels and avoid chronically elevated insulin over time.

Insulin is an essential hormone that helps the body manage nutrients, regulate blood glucose, and store energy when needed. What matters is how effectively the body responds to insulin and whether that system continues to work well over time. ^[1,8]

At its core, supporting insulin sensitivity is part of supporting the body’s ability to use, store, and manage energy effectively. That is one important piece of the bigger picture of metabolic health.

References

1. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). What Is Diabetes? U.S. National Institutes of Health. https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes

2. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Insulin Resistance & Prediabetes. U.S. National Institutes of Health. https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/prediabetes-insulin-resistance

3. Biochemical and cellular properties of insulin receptor signalling. Nature Reviews Molecular Cell Biology. 2018. PMCID: PMC5894887.

4. The Effect of Regular Exercise on Insulin Sensitivity in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis. Journal of Diabetes Research. 2016. PMID: 27535644.

5. Overall and Sex-Specific Effect of Berberine on Glycemic and Insulin-Related Traits: a Systematic Review and Meta-Analysis of Randomized Controlled Trials. 2023. PMID: 37598753.

6. An updated systematic review and dose-response meta-analysis of the effects of alpha-lipoic acid supplementation on glycemic markers in adults. Nutrition. 2021;82:111041. PMID: 33199187.

7. Moridpour AH, et al. The effect of cinnamon supplementation on glycemic control in patients with type 2 diabetes mellitus: an updated systematic review and dose-response meta-analysis of randomized controlled trials. Phytotherapy Research. 2024;38(1):117-130. PMID: 37818728. DOI: 10.1002/ptr.8026.

8. Bikman B. Why We Get Sick: The Hidden Epidemic at the Root of Most Chronic Disease-and How to Fight It. BenBella Books; 2020. The bouncer/doorman analogy used in this article is adapted from Bikman’s explanation of insulin and insulin resistance.

Note: This article is for educational purposes and is not intended to diagnose or treat a medical condition.