Once-a-Week Insulin Explained: How It Works, Who Needs It & Basal vs Bolus Insulin
If you have diabetes and have lost weight that you now want to regain, the newly launched once-a-week insulin could turn out to be a real blessing for you. But to understand why, you first need to understand what is insulin, how the natural insulin in your body works, and who this new weekly insulin actually suits.
In this blog we will explain, in very simple language, what insulin is, what its role is in the body, how it controls blood sugar, what basal and bolus insulin mean, what insulin resistance is, and finally what the new once-a-week insulin is and who it may be best for. This is educational information to help you understand your body better and have a more informed conversation with your doctor.
What Is Insulin and Where Is It Made?
Insulin is a hormone produced by a gland called the pancreas, located on the left side of your body. The pancreas makes this insulin hormone and releases it into the blood. Insulin is made of protein, and protein is made of amino acids, so insulin is essentially a chain of amino acids.
When we look at the structure of insulin, it has two amino acid chains, called the A chain and the B chain. The A chain has 21 amino acids and the B chain has 30 amino acids, and the two chains are connected to each other. This is the basic structure of the insulin hormone. Understanding this structure matters, because it is exactly what scientists modified to create the new long-lasting insulin.
What Is the Function of the Insulin Hormone in the Body?
The function of insulin hormone in the body comes down to two major jobs.
Role 1: Growth, Repair and Body Maintenance
Insulin plays a key role in the body's growth, repair and development. Whenever there is wear and tear in the body and new tissue needs to be built, insulin is involved. For this, the body needs a basic constant level of insulin called basal insulin. Around the clock, your blood needs roughly 5 units of insulin at all times so that your body's basic repair and growth work keeps running. If this baseline drops below the required level, the body starts losing weight. This is why some diabetics keep losing weight without trying.
Role 2: Moving Glucose Into Cells After Meals
When you eat food, the glucose from that food enters your blood after digestion. But glucose cannot move from the blood into your cells automatically. It needs insulin. Insulin grabs the glucose and puts it inside the cell. This insulin, which is needed after eating, is called bolus insulin. So there are two requirements: basal insulin for baseline needs, and bolus insulin for after-meal needs.
| Feature | Basal Insulin | Bolus Insulin |
|---|---|---|
| Purpose | Background level for repair and growth 24 hours | Handles glucose spike after meals |
| When needed | Constantly, all day and night | Only when you eat |
| Body requirement | Around 5 units baseline at all times | Varies with meal size |
| If too low | Body starts losing weight | Blood sugar spikes after eating |
| Once-a-week insulin covers | Yes, this is basal | No, does not cover meal spikes |
How Does Insulin Work? The Cell and Receptor Mechanism
To understand how insulin works, picture a cell with a reception area on its outer surface. Sitting at that reception is what we call the insulin receptor. Think of the receptor as a receptionist standing with arms open, waiting for insulin to arrive. This receptionist is connected to the inside of the cell like an electrical wire.
Insulin, released by the pancreas, floats through the blood. When it reaches the open reception area, the insulin attaches to the insulin receptor. The moment it attaches, an electrical signal is generated, and this signal travels inside the cell like current through a wire. Step by step, a series of reactions begins inside the cell.
Inside the cell there is a glucose catcher. When the signal arrives, this glucose catcher activates, reaches out from the other side of the cell, grabs glucose from the blood, and pulls it inside. Slowly, glucose starts entering the cell. Once enough glucose is inside, the cell sends a signal that it no longer needs glucose, the receptor is pulled inward, the insulin attached to it is destroyed by the cell's internal security system, and the glucose catcher withdraws. This is the complete cycle of how insulin moves blood sugar into your cells.
What Happens to Extra Glucose Inside the Cell?
Once glucose is inside the cell, it has two possible uses. First, it provides energy by releasing ATP, which the cell uses for its functions. Second, if too much glucose comes in beyond what is needed, the excess is converted and stored. Some of this extra glucose can be turned into cholesterol, which the cell releases back into the blood. The rest can be converted into triglycerides and stored inside the cell as fat.
Why Natural Insulin Only Survives 15 to 20 Minutes
Here is a very important point. The insulin your pancreas produces only stays alive for about 15 to 20 minutes. In that short time it either helps glucose enter cells, or it circulates through the blood back toward the liver, where the liver's security system catches and destroys it. Then new insulin is produced, which also dies in 15 to 20 minutes, and the cycle continues. This means your pancreas is constantly producing fresh insulin around the clock.
This short lifespan creates a problem for diabetes treatment. If you gave a patient natural insulin by injection, you would need to inject it every half hour, because that is how quickly it gets destroyed. That is completely impractical. This is the exact problem that scientists set out to solve, and it led to a major breakthrough.
What Is the New Once-a-Week Insulin and How Does It Last So Long?
Scientists wanted to create an artificial insulin that could last a whole week instead of dying in 20 minutes. These modified insulins are called insulin analogs. Just like paneer analog looks like paneer but is not exactly paneer, an insulin analog looks like insulin and works like insulin, but is not exactly the same as natural insulin.
The once weekly insulin has two major changes in its structure. First, a few amino acids in the sequence are removed and replaced with different ones. Second, and this is the real scientific breakthrough, scientists attached a fatty acid tail to the insulin.
The VIP Bus Analogy
To understand why the fatty acid tail matters, you need to know about a protein in your blood called albumin. Albumin is a transporter protein that constantly circulates in the blood. Think of albumin as a VIP bus. To board this bus you need a VIP pass, and once you are on the bus, you get security, meaning nothing can destroy you while you are inside, and you can get on and off wherever you like.
The fatty acid tail that scientists attached to the weekly insulin acts as that VIP pass. It lets the insulin board the albumin bus, where it is protected. This bus has a lifespan of about three weeks, so theoretically an insulin that boards it can stay protected for a long time. From inside the bus, the insulin gets released slowly, one or two molecules at a time, doing its work gradually. Neither the liver nor the cells can destroy it quickly. This is why a single injection can keep releasing insulin slowly for a whole week. It is a genuinely big discovery for diabetes management.
Why Keeping Blood Glucose Low Matters So Much
To understand why diabetes management is so important, look at the composition of blood. In your blood, glucose is actually the smallest component at only about 0.1 percent, because higher glucose is toxic to the body.
| Component in Blood | Approximate % | Note |
|---|---|---|
| Water | ~90% | Base of blood, carries everything |
| Protein (like albumin) | About 8% | Albumin acts as a transporter |
| Minerals (sodium, potassium, calcium) | Small amount | Electrolyte balance |
| Glucose | ~0.1% | Normal, healthy range |
Watch how narrow the safe range is:
| Blood Glucose Level | What It Means |
|---|---|
| 0.1% | Normal, healthy range |
| 0.2% | Diabetes range |
| 0.5% | Danger, person can go into coma |
| 0.8% | Life threatening, death possible |
The Real Foundation of Diabetes Management: Controlling Glucose Load
This is the key insight that ties everything together. Whether someone uses the new weekly insulin or not, the foundation of managing diabetes is reducing the glucose load of the diet. When the diet's glucose load is lower, blood glucose stays balanced, less glucose is converted into triglycerides and cholesterol, and the body's own insulin, or any injected insulin, does not have to fight an uphill battle.
This is exactly why diet comes first in any serious diabetes plan. If you keep eating a diet that is 60 to 80 percent carbohydrate, no insulin can fully fix your numbers. But if you bring your carbohydrate ratio down and choose foods with a low glucose load, everything else becomes easier to manage. This is why so many people focus on switching their daily staples, like their atta, to genuinely low glucose load options, because rotis are eaten at almost every meal and quietly drive a large part of the daily glucose load.
If you want to reduce the glucose load of your everyday meals, low glucose load foods like those made by Diabexy are designed for exactly this purpose. You can explore them at diabexy.com. Diabexy is India's number one diabetes education platform, trusted by more than 2 million people. Our mission is to eradicate diabetes from India the way polio was eradicated, through the right knowledge and the right food. We make India's first low glycemic load foods including Sugar Control Atta, Sugar Free Sweetener Drops and the EGL Chart covering 300 plus Indian foods.
Who Should Use the Once-a-Week Insulin?
The once-a-week insulin is a basal insulin. It maintains your baseline level. It does not cover the glucose spike after meals, because you inject it once and it releases slowly over a week. To find out whether your baseline insulin needs support, doctors use a test called the C-peptide test. If the C-peptide value is below 1, it suggests your body is not producing enough of its own insulin at the baseline level, and your weight may start dropping. If C-peptide is above 1, meaning 1.5, 2 or 3, the pancreas is producing enough and external basal insulin is usually not needed.
Based on this, two types of candidates may benefit from the weekly insulin:
- Candidate 1: Someone whose C-peptide is slightly below 1, say 0.9, who already eats a low glucose load diet but whose blood glucose still does not normalize and whose weight keeps slowly dropping every month. A weekly basal insulin can maintain their baseline so they stop losing weight.
- Candidate 2: Someone whose C-peptide is around 1, who follows a low glucose load diet and maintains weight, but whose blood glucose is not controlled as well as others on the same diet. A little extra basal insulin may help control their blood glucose more easily.
How Is the Dose Decided?
The insulin dose should never be started at a high level, especially with weekly insulin, because it stays in the body for a week. If you inject a high dose on one day, it could create hypoglycemia, meaning dangerously low blood sugar, for the entire week. So doctors always start low.
A rough way to calculate: since the basal requirement is around 4 to 6 units per day, you multiply by seven days to estimate the weekly need, which might come to around 40 units. You start with this and observe the response, then increase gradually, perhaps by 10 to 15 units at a time, never suddenly. This is why it is essential to discuss your C-peptide, insulin level, blood glucose level and diet with your doctor before deciding the dose. Once these are known, determining the right dose becomes much easier.
If you want a consultation or help discussing this with a doctor, the Diabexy diabetes coaching team can guide you and arrange a doctor consultation if your situation requires it. You can reach them through diabexy.com.
Watch the detailed video explanation of once-a-week insulin and how it works
Frequently Asked Questions
Insulin is a hormone made by the pancreas, a gland on the left side of the body. It is made of protein, specifically two connected amino acid chains, an A chain of 21 amino acids and a B chain of 30 amino acids. Insulin has two main functions. First, it maintains the body's baseline repair and growth through a constant background level called basal insulin. Second, after you eat, it moves glucose from the blood into your cells, which is called bolus insulin. Without insulin, glucose cannot enter cells on its own, so blood sugar rises. This is the core reason insulin is central to diabetes.
Basal insulin is the constant background insulin the body needs 24 hours a day, around 5 units at all times, to run basic repair, growth and maintenance and to keep body weight stable. Bolus insulin is the extra insulin needed specifically after meals to handle the glucose that enters the blood from food. Basal is always needed, day and night, while bolus is only needed when you eat. The new once-a-week insulin is a basal insulin, meaning it maintains the baseline level over a week but does not cover the after-meal glucose spikes, which still need separate management.
Insulin works through a receptor on the cell surface. When insulin attaches to this insulin receptor, it triggers an electrical signal inside the cell, which sets off a chain of reactions. This activates a glucose catcher inside the cell that reaches out, grabs glucose from the blood, and pulls it in. Once enough glucose has entered, the cell signals that it is full, the receptor is pulled inward, and the insulin is destroyed. Inside the cell, glucose is either used for energy or, if in excess, converted into cholesterol or triglycerides for storage. This is why excess glucose in the diet leads to higher cholesterol and fat.
Natural insulin produced by the pancreas survives only about 15 to 20 minutes in the blood. In that time it either helps move glucose into cells or circulates back to the liver, where it is broken down. The pancreas therefore has to produce insulin continuously. This short lifespan is why injected natural insulin would need to be given every half hour, which is impractical. To solve this, scientists created insulin analogs with a fatty acid tail that lets the insulin attach to the albumin protein in blood, protecting it and allowing it to release slowly. This is the basis of long-acting and once-a-week insulins.
Once-a-week insulin is a basal insulin suited to selected people, not everyone, and only under a doctor's guidance. It may help two types of candidates. First, someone whose C-peptide test value is slightly below 1, who eats a low glucose load diet but still cannot normalize blood glucose and keeps slowly losing weight, since the weekly insulin maintains their baseline and prevents weight loss. Second, someone with a C-peptide around 1 who maintains weight on a low glucose load diet but whose blood glucose is not well controlled, where a little extra basal insulin helps. A C-peptide test and doctor consultation are needed to determine suitability. Insulin is a prescription medicine and must never be used without medical advice.
Insulin plays a direct role in body weight. A healthy baseline level of insulin, called basal insulin, is needed for the body's repair and growth functions and to maintain weight. If this baseline insulin falls too low, which can happen when the pancreas is not producing enough, the body begins to lose weight, which is why some diabetics keep losing weight unintentionally. On the other hand, insulin also moves glucose into cells where excess can be stored as fat, so too much insulin combined with a high glucose load diet can contribute to weight gain. Balanced insulin, along with a low glucose load diet, supports healthy weight in either direction.
Diet is the foundation of diabetes management and directly affects insulin needs. When the diet's glucose load is high, more glucose floods the blood, demanding more insulin and putting strain on the pancreas, while excess glucose gets converted into triglycerides and cholesterol. When you reduce the glucose load by lowering the carbohydrate ratio and choosing low glucose load foods, blood glucose stays balanced and the body's own insulin, or any injected insulin, works more effectively. While people who need insulin should always follow their doctor's advice, improving the diet's glucose load is a key part of any diabetes plan and can make blood glucose much easier to control. Since rotis are eaten at almost every meal, switching to a low glucose load atta is one of the most effective dietary changes.
Understand how it works. Control your glucose load. Work with your doctor.
