Diabetes mellitus, commonly known by the shortened name “diabetes”, sugar diabetes or "sugar", is one of the most frequent and important medical disorders of both humans and cats. As a pet owner with a newly diagnosed cat with diabetes, it is difficult to know what you need to do. We created this article to help you know step by step what you need to know and what you need to do.
The 6 keys to treatment of diabetes in cats include:
- Change your cat's diet
- If your cat is overweight – help your cat lose weight! (this is critical)
- Give insulin every 12 hours
- Monitor for response to treatment
- Maintain a consistent diet, exercise and insulin treatment plan
- Monitor for complications of the disease
We will help you understand more about diabetes, how and when to give insulin how to deal with complications. We also included answers to the most common questions diabetic cat owners have as they start their journey as a diabetic cat owner.
What is Diabetes?
Diabetes is a disease that leads to chronic elevation of the blood glucose or sugar. Blood sugar is maintained by a group of hormones, the most important of which is insulin, which is manufactured by the pancreas, a small organ near the intestines. Insulin lowers the blood sugar after a meal, and deficiency of insulin, or an insensitivity of body cells to available insulin, leads to diabetes.
With good care, your cat can have a very good life with diabetes. We will help tell you how.
What Cats Get Diabetes?
Diabetes mellitus usually affects middle-aged to older cats of either sex. The peak age seen in cats is 11 years. Juvenile-onset diabetes may occur in cats less than 1 year of age but is uncommon. Any breed can be affected but some breeds are at higher risk.
Breeds at increased risk for diabetes mellitus include Burmese cats.
What Causes Feline Diabetes?
The cause of diabetes has a lot to do with genetics and bad luck. There are risk factors which can potentiate diabetes such as obesity, recurring pancreatitis, Cushing's disease (hyperadrenocorticism), and drugs such as glucocorticoids and progestogens that antagonize insulin.
What are Common Symptoms of Diabetes?
Common symptoms of diabetes in cats include thirst and increased water consumption among others. For more detailed information about the diagnosis, treatment and complications of diabetes, go to: Diabetes in Cats.
Uncontrolled elevation of glucose leads to dehydration and body chemistry disorders that can eventually cause coma and death. Left uncontrolled, diabetes can become life threatening.
Why Does My Diabetic Cat Urinate More?
When a pet is diabetic, the body tries hard to fix the problem. For example, the kidneys will try to get rid of excess glucose in the urine. To get rid of extra glucose they also end up getting rid of a lot of extra water. So they urinate more. Because they urinate more and are getting rid of a lot of extra water, they are thirsty and drink more.
Classic signs of diabetes is drinking more and urinating more. The medical term for this is polydipsia (drinking more) and polyuria (urinating more).
What Does the Term Spilling Glucose Mean?
Some clients hear their vet say this term – their cat is “spilling glucose”. This term means that their cat has glucose in the urine. This is the body's way of trying to get rid of excess glucose in the cat's blood.
How is the Diagnosis Obtained?
The first step in treating diabetes in your cat is getting a correct diagnosis. This requires a veterinary examination and appropriate tests, such as a urinalysis (to detect spilled "sugar") and blood glucose determination. Additional tests often are needed to assess the overall medical situation. Once the diagnosis is made, however, you and your veterinarian can work together to effectively control diabetes mellitus.
What Type of Diabetes Does My Cat Have?
There are two basic forms of diabetes: type I and type II. Absolute deficiency of insulin leads to type I diabetes. This is due to an insufficient number of insulin-producing pancreas cells. Type I diabetes, often called "juvenile-onset diabetes" in people, and represents the most serious form of the disease. Effective treatment for type I diabetes requires a combination of controlled diet, regular exercise and insulin therapy.
Cats are most often affected by type I diabetes and rarely have type II. People and pets with type I diabetes require daily injections of insulin to maintain a regular blood-sugar level.
Adult onset or type II diabetes is the more common form of diabetes in people. This condition combines a relative lack of insulin production with a resistance of body cells to the effects of the hormone. Type II diabetes is treated with a combination of diet, weight control and medicine that makes cells more sensitive to insulin. This form of diabetes is observed more often in cats than in dogs. Keys to successful treatment are a high-fiber diet, weight control and occasionally, medicines designed for humans to control the glucose level.
How Do I Treat Diabetes?
The treatment of diabetes requires the administration of injectable insulin to drive sugar molecules into the body's needy cells. Dietary changes will help.
In cats, weight loss and dietary changes will often suffice for long term treatment of diabetes.
You will need to learn how to give your cat insulin as well as how, what and when to feed your cat.
For cats that are extremely ill, they will require hospitalization until the diabetes is under control.
What Should I Expect From My Vet?
Every veterinary clinic and vet is a little different in how they schedule rechecks following the diagnosis of diabetes.
One approach is as follows (and may vary with your individual veterinarian):
- The first appointment should include information about diabetes, demonstrate how to give insulin, and dietary recommendations.
- A recheck should be scheduled in one week that includes a clinical examination, history of the symptoms, a serum fructosamine level and a 12 hour blood glucose curve to be performed at the hospital. Treatment should be adjusted if necessary. Some vets will discuss the advantages of home monitoring and see if they you are interested in doing this at home. If you are interested in doing home monitoring, you'll need to order the monitor and strips before your next appointment.
- Two weeks later another recheck is performed. (Providing everything is okay), which is 3 weeks from the original diagnosis. At this appointment you may learn how to perform home monitoring techniques with your glucometer. You vet's office should show you how to use this machine and allow you to demonstrate how to obtain a blood glucose on your cat. You should also learn to calibrate your machine.
- Additional rechecks should be scheduled as needed which ends up being monthly for 3 months, then every 2 months for 2 visits then every 6 months if things are going well.
- When you are comfortable with using the glucometer at home, testing the blood glucose before your cat eats is recommended twice weekly for at least a month to help determine signs of a low blood sugar. If the blood sugar is less than 100 mg/dl – call your veterinarian to determine if they want to lower the insulin dose.
- If you will be doing home glucose curves, they should be done prior to your monthly appointment. Results should be emailed, faxed or dropped off prior to the appointment if possible. This will give your vet time to reevaluate and recommend any adjustments. Coordinate what schedule works best with your veterinarian.
Will My Diabetic Cat*s Need to be Hospitalized?
If your pet has stopped eating, has been vomiting, and is generally not doing well; chances are we will admit your cat into the hospital to begin treatment. This often happens when the diabetes mellitus has progressed and the body will produce ketones.
Because the body has not been able to use glucose as its energy source, instead it will begin to use its fat. When the body burns fat for energy, a by-product known as ketones are created and unfortunately they are toxic. Ketones can be found in urine samples.
Once ketones are present the animal will continue to decline rapidly unless treatment begins. The presence of Ketones changes the diagnosis to Diabetic Ketoacidosis which can be complicated to treat.
Diabetic ketoacidosis (DKA), the most severe form of Diabetes Mellitus, results in severe changes in blood chemicals including imbalances in small, simple chemicals known as electrolytes.
In-hospital therapy generally includes insulin administration with frequent dose adjustment (every few hours), intravenous (IV) fluids, administration of electrolytes (blood chemicals), treatment of secondary problems, and antibiotics. Multiple blood glucose samples are taken to determine the insulin dose and urine samples to determine the presence of ketones. The insulin given in this situation is a short acting insulin and will not be the insulin used when you go home.
The process is slightly different with every cat but will generally require two to four days of intense hospitalization.
What are Signs of Diabetic Keotacidosis (DKA)?
Symptoms include weight loss, lack of appetite, increased thirst, frequent urination, lethargy, disorientation, vomiting, and some people notice a fruity smell to the breath (acetone odor).
If you suspect your cat is having symptoms of DKA, this is a life-threatening emergency. Call your veterinarian immediately. Treatment includes hospitalization, intravenous fluids, and frequent doses of short-acting insulin. For more information, go to: Diabetic Ketoacidosis (DKA) in Cats.
Beginning Treatment With Your Diabetic Cat
If your pet is still feeling good, eating with no vomiting, you will be taught to give insulin injections to your cat and start them on a special diet. Below is information on what and when to feed your diabetic cat.
The goal of diabetes treatment is to control the blood glucose so it is close to the normal range, as it would be if the pancreas were still producing insulin naturally.
In cats, the ultimate goal is for diabetic remission. This is possible in diagnosed obese or previously obese cats. Dietary therapy and weight loss are essential in addition to the insulin therapy.
What Diet Should I Feed My Diabetic Cat?
Your cat's weight and what your cat eats has a direct impact on his blood glucose levels. Diet is thought to be a CRITICAL part of diabetes management in cats.
Current research suggests that a high protein, low carbohydrate diet is best for cats. Cats are obligate carnivores and they don't they don't have the proper enzymes to digest plant-based protein. So offering them plant based foods can be difficult for the diabetic cat to digest and process. Feeding to obtain and ideal body weight is critical.
Excellent foods include:
- Hills Science Diet m/d dry and canned
- Purina veterinary diets DM dry and canned
- Royal Canin diabetic DS 44 dry
- Young Again
Previously, diets high in fiber and complex carbohydrates were recommended for dietary management of diabetic cats. These are not longer recommended.
Several studies have shown that cats started on insulin and a high-protein and low-carbohydrate diet were 4 times more likely to achieve clinical remission of their diabetes. In cats that did not achieve remission, their insulin requirement was reduced by half.
Canned diets are significantly lower in carbohydrate content than most dry kibble and often can help in better dietary management of diabetes.
IMPORTANT: The most important aspect to a diabetic diet is that it be complete, balanced, your cat likes it, you are feeding the calories your cat needs and you are consistent. Feed the same food and the same amount of calories every day. This will help keep glucose levels steady.
How Do I Calculate How Many Calories My Cat Should Eat Per Day?
Your vet can help you with this. Here is a method for calculating your cat's calorie requirements.
Can I Treat My Cat with Diabetic Pills?
Oral anti-hyperglycemic pills are commonly used in humans to treat adult onset type II diabetes. Some cats can respond to oral medications for milder cases of diabetes with very strict weight loss and diet modifications. Some studies suggest it can take 3 to 4 months for cats to optimally respond to oral medications. Common medications used in cats include: Glipizide.
Severe cases of diabetes are only controlled with insulin injections.
My Cats Hates His New Food, What Should I Do?
If your cat won't eat his new food, go back to his regular food for a while. It is important that your cat eat. Then do a gradual change. Mix in maybe 10% the new food with 90% of the prior food. Each day, add a few more kibbles of the new food to the old food until have obtained a 100% change to the new food. If he still will not eat the new diet, refer to the list of recommended foods above and discuss a different option with your veterinarian.
When Should My Cat Eat?
For cats that are getting insulin twice daily, it is recommended to split the daily calories in to two meals, which are fed before the insulin dose.
For cats on once daily insulin, they should be fed also twice daily with the first meal before the insulin injection and the second meal at the time when the insulin peaks which can be determined based on knowledge of the insulin and the glucose curve.
Most diabetic cats are fed twice daily. Give ½ of the daily calories approximately 30 minutes before the insulin injection. After your cat eats, his blood glucose will naturally increase. The insulin will help drive the glucose levels back to a normala normal level. Give the other half of the daily calories before the second insulin injection (this is assuming you are giving insulin every 12 hours).
Another method is to feed your diabetic cat ¼ of its daily calories in the morning before the insulin injection, and another ¼ of the calories 6 hours later when the insulin is peaking, another 1/4 of the calories at dinner and the last fourth 6 hours later.
Can I “Free Feed” My Cat?
Free feeding is a term that refers to having food in the bowl all the time and allowing your cat to eat when he wants.
Many cats with diabetes are on a strict consistent feeding schedule. However, this can be difficult for some cats. This may work better for cats that are nibblers and not food motivated.
Scheduled feedings work best on cats even though they may prefer small frequent meals. The idea behind meal feeding is that you can observe your cat and ensure he or she eats prior to insulin administration.
For cats that want to eat more frequently, you can use timed feeders so your cat can eat several times during the day but allows you to control calorie intake.
Can My Cat Get Treats?
Diabetic cats can get treats as long as they are approved by your vet. Generally treats that are low in sugar and carbohydrates are ok. Larger treats can even be broken up into small pieces to provide multiple treats.
Treats can be given as a reward for blood glucose testing or when the blood glucose is at its lowest – approximately 4 to 8 hours after injection.
Good treat options include: baby carrots, snap peas, broccoli, cauliflower, green or red peppers, canned pumpkin, tofu, a kibble of your cat's regular cat food, and/or freeze dried meat treats. Recommended commercial treats Stella & Chewy's Carnivore Crunch, or other all natural freeze dried meat or fish treats.
Some diabetic cat owners make their own treats by taking an approved canned cat food and using that is as the base to make treats. They generally will empty the can onto a cookie sheet, smash down to about ¼ to ½ inch thickness and bake at 375 degrees Fahrenheit until dry and crispy. Some foods can be refrigerated and sliced, then baked the same way. Store baked treats in the refrigerator in a sealed container.
The calories in the treats should be considered in the overall calories requirements for the day. Treats should be given in moderation.
How Should I Exercise My Cat?
Regular exercise is good for your cat. It can help lose or maintain weight and lower the blood sugar.
The best approach to exercising your diabetic cat is to do it regularly and routinely. Try to do the same amount of exercise every day at the same time.
Large changes in exercise routines can change insulin requirements. An unusually long or vigorous play session can cause the blood sugar levels to drop too low. If you plan a change in your cat's routine, do it slowly and gradually.
What is Insulin?
Insulin is a hormone that is formed and released by beta cells residing in the pancreas. Eating prompts the release of insulin. When insulin is not produced in sufficient quantities, it can be administered in the form of an injection.
There are various types of insulin treatments, each with a different duration of effectiveness.
A bottle of insulin is commonly referred to as a vial. All insulins are measured in units.
There are two common concentrations which will be important when you buy your insulin syringe. Some insulin's are u-100 (100 units in a milliliter) and others are u-40 (40 units in a milliliter). Because insulin's are different, 3 units of one insulin may not be the same as 3 units of a different insulin. It is very important to verify the type of syringe and insulin match when filling your prescription to avoid over- or under-dosing your pet.
There are several different types of insulin used on cats. They differ by what they are made from (some are pork, some are human-based) and how long they act in the body. The short acting insulins are referred to as “regular”, medium acting are referred to as “Lente” and long acting insulins are referred to as “Ultralente”.
The insulin's used in cats are generally different from dogs.
The most commonly used insulin's in cats are:
- Humulin (human-based) but there are other types used, too.
- Humulin N can be used in cats but has not been
- Pork or beef PZI insulin's are the closest in structure to cat insulin and seem to work best.
NOTE: There are several types of insulin on the market. What works on one pet may not work on a different pet.
How Often Does my Cat Need Insulin?
Your veterinarian will determine this but based on the insulin's available in the U.S. for cats, the most effective treatment for diabetes in cats is administration of insulin with intermediate duration of action twice daily.
The only currently available intermediate-duration product is recombinant human neutral protamine Hagedorn (NPH) insulin.
Another type of insulin can be used in called Porcine Lente insulin (Vetsulin). At the present time, it is not being sold in the United States due to problems with stability and bacterial contamination associated with the manufacturing process. Based on our sources, it is uncertain when or if the product will again be available in the United States.
Why Does My Cat Need Insulin?
Insulin is required for food to be properly processed and utilized as energy for the body. Insulin lowers the blood sugar after a meal. Deficiency of insulin, or an insensitivity of body cells to available insulin, leads to diabetes.
The goal of diabetes treatment is to supplement the insulin to regulate the blood glucose in as close to a normal range as possible.
How Should the Insulin Look?
The first time you open your insulin – look at the color and clarity of the bottle most types of insulin will look slightly cloudy but there should be no clumps or floating particles.
How Much Insulin Do I Give My Cat?
The initial dose of insulin given is 1/8 to 1/4 of a unit per pound of body weight given every 12 hours.
For example, a 10-pound cat may start on 1 units of insulin total. A lower dose is generally recommended with a gradual increase. It is better to start low and gradually allow the body to acclimate to the disease and avoid signs of hypoglycemia (low blood sugar).
How Do I Give the Insulin Injection?
Insulin is generally given under the skin (subcutaneous) over the back. The location of the injection should be rotated with every injection. The general method for giving insulin is as follows:
Gather your equipment to give the insulin injection. The bottle of insulin, syringe, cotton ball, alcohol…and your glasses if you wear them (It can be difficult to see the small print on the numbers).
- Take the bottle of insulin out of the refrigerator.
- Gently roll the bottle in your palms to mix. Do not shake!
- Clean the top medication bottle with an alcohol coated cotton ball
- Insert the needle and syringe into the rubber top of the insulin vial
- Invert the bottle and draw up the prescribed amount of insulin by pulling back on the plunger of the syringe until the syringe is full to the desired mark
- Make sure there are no air bubbles in the syringe.
- Identify the area you want to inject. Using the skin between the shoulder blades. The skin does not need to be cleaned with alcohol prior to administering these medications.
- Hold the syringe with the needle exposed in one hand.
- With the other hand, gently lift a small piece of skin between the shoulder blades, at the base of the neck.
- By lifting the skin, an upside down "V" will be formed by the tent in the skin. Insert the needle into the center of this "V" or tented area of skin.
- Once the needle is inserted into the skin, draw back slightly on the syringe plunger and make sure no blood flows into the syringe.
- If no blood is seen in the syringe, push the plunger into the syringe in order to administer the medication.
- Let go of the skin and make sure there is no liquid on the surface of the skin. If there is moisture on the skin, you may have inserted the needle through all layers of skin and out the other side of the tented skin. If this occurs, contact your veterinarian before another attempt is made.
What If I get Air in My Syringe?
Air in the syringe means that you will not get the correct dose of insulin.
If you are drawing up your insulin, you have the syringe in the vial of insulin and you see you are getting air, inject the insulin (and air) that is in the syringe back in the bottle. Try again. You can sometimes gently tap the syringe (flick the syringe case with your index finger) to encourage the air bubble to go to the top to dispose.
If you have taken the insulin out of the bottle and notice that there is air in the syringe, the best approach is to dispose of that insulin and pull up the correct dose.
When Should I Give the Insulin?
Most cats are on twice daily insulin. This should be given 12 hours apart. As you start therapy on your diabetic cat, pick a time that works for you that is 12 hours a part. For some pet owners, this may be 6 am and 6 pm. For others it may be 4 am and 4 pm. Whatever works for you is fine. Try to give the insulin within an hour of the scheduled dose time.
If you give insulin once daily – give it at the same time every day.
How Do I Store My Cats Insulin?
Every insulin is slightly different. Most all are sensitive to light. Some manufacturers recommend that the insulin be stored in the refrigerator and others are ok at room temperature. It should always be stored out of direct light. I generally recommend that when you open a new box with insulin – mark the date on the box with permanent marker and keep your insulin stored in the box.
All insulin's are sensitive to extremes in temperature such as heat and freezing. Review the manufacturer's recommendations for storage and for expiration dates.
Most commonly used insulins have the following recommendations:
- Unopened vials should be kept in the refrigerator
- Toss any expired insulin
- Do not freeze insulin
- Do not exposure insulin to the sunlight
How Long Does the Insulin Last?
Please follow the recommendation from your veterinarian. Some insulin manufacturers recommend a new vial be started every 30 days and others recommend every 3 months. Realistically, very little insulin is used in 30 days for most cats. This is the ideal recommendation.
Most veterinarians recommend that the cat owner examine the insulin daily to ensure there are no clumps, particles that won't dissolve or an abnormal color. Dispose of the bottle when it expires (check date on the bottle) or 6 months after it is opened. Most insulin's have been found to stay effective for this time.
It is possible that as the insulin ages, it becomes less effective.
When opening a new bottle, write the date on the bottle or box and in your calendar.
Why Do I Need to Roll the Insulin Bottle?
It is recommend to gently “roll” the insulin bottle to disperse the powdered insulin in the liquid. Shaking can damage the insulin molecules.
To roll the bottle, place it between the palms of your hands and gently a roll it between your palms 2 to 3 times. This is enough to disperse the insulin.
If you draw a dose of insulin that isn't properly mixed, you may either get too much or not enough of the proper concentration. Some insulin's settle out very quickly so it is recommend to gently roll the bottle between your palms a few times to disperse the contents then immediately draw the insulin in the syringe.
Why Can't I Shake My Cats Insulin?
Gently rolling of the insulin between your palms is all that is needed to gently mix the insulin. The insulin is a very fine powder that is suspended in the liquid.
Rolling the insulin is better for a few reasons:
First, shaking denatures the protein, hurts the insulin molecule so it doesn't work correctly.
Second, shaking creates air bubbles, which can also act to denature the protein, inactivating the insulin. The air also makes it more likely to pull up air bubbles in the syringe that are hard to remove. If you include the air in your dose, then you are not giving the proper dose to your cat.
How Much Insulin Should You Keep On Hand?
It is recommended that you keep a spare vial of insulin on hand. This way if you happen to be out or drop and break a vial, you have a spare.
Diabetic pet owners will tell you it is no fun trying to find insulin on the weekend if something happens.
Can I Freeze My Insulin to Preserve it?
Insulin is delicate. Freezing will render the insulin inactive.
My Insulin has Clump or Particles That Aren't Dissolving
If you notice clumps in your insulin, particles that won't dissolve, an abnormal color or anything else that seems suspicious, stop using that vial and dispose.
Open a new insulin bottle for use.
What Type of Insulin Syringe Should I Use with My cat?
There are three things you need to know when buying insulin syringes.
- Type of insulin (U-40 or U-100)
- Size of the needle (gauge)
- Volume you want the syringe to hold (generally come in ½ milliliter or 1 milliliter (ml)
- Type of Insulin - It is critical that you use the insulin syringe that matches the insulin. Most insulin types used in cats is what they call U-100 insulin. This means there are 100 units of insulin in a volume of 1 ml. The insulin syringes should indicate they are also U-100. Some of these syringes will hold ½ ml (50 units and others will hold 1 ml (100 units). If your cat is on more than 50 units per dose of the U-100 insulin, you will need the 1 ml syringe.
Some insulin is U-40 (which means there are 40 units in a milliliter) and should only be used with U-40 syringes. Using the wrong syringe type can cause either a massive overdose or underdose of medication.
Again, it is critical that you use the insulin syringe that matches the insulin.
- Size of the needle. The gauge is the size of the needle diameter. The lower the number, the bigger the needle. The higher the number, the smaller the needle. A 31-gauge needle is smaller than a 29-gauge needle (although both are very small). To put it in perspective, most blood is drawn with a 22 gauge needle. The smaller needle is generally preferred but some needles can be too small and have difficulty going through the skin of some thicker skinned pets.
- Volume size. Syringes generally come in a ½ ml and 1 ml volume size. This means the syringe will hold less with a ½ ml syringe and more with a 1 ml syringe. If your cat is on a small dose of insulin such as under 25 units of the U-100 insulin - it is easiest to use the 50-unit syringe. It is easier to see the numbers and be accurate when pulling up the insulin dose.
When you go to the pharmacy to buy syringes make sure you buy the one that works with your insulin. Know if you need U-100 or U-40.
A commonly used syringe is a 31 gauge (which is a very small needle). For example, this is a common syringe size that cat owners like:
U-100 - Ultra thin 31 gauge 0.5 cc - 5/16” short needle
What If I have U-40 Insulin and U-100 Syringes?
There is a formula to convert U-40 and U-100 syringes. Go to this Link.
How do You Convert Insulin Units to Milliliters?
Ideally, if you have the insulin and syringes that match – you don't need to do this. Mistakes happen when pet owners start trying to do various conversions.
U-100 means there are 100 units in 1 milliliter.
30 units of a U-100 insulin are equal to 0.3 milliliters (0.3 ml).
I have a chart that will help you. Go to: How to Convert U-100 Insulin in Units to Milliliters.
Where Can I Buy Insulin Syringes?
You can buy your insulin syringes from your vet or at most pharmacies. You don't need a prescription to buy them. You can also buy them online at several pharmacies. Choose a pharmacy with which you are familiar and comfortable. It is important to be frugal but there have been reports and recalls of insulin syringes that are mismarked from low cost syringe producers.
Insulin syringes are cheapest by the carton, which contains 100 syringes.
How Many Times Can I Use the Insulin Syringe?
Insulin syringes are made to be disposable, to be used once and tossed. However we as veterinarians and pet owner care givers are frugal. Boxes of 100 needles run about $20 to $45 dollars depending on where you shop.
If you are using 2 syringes a day – that is 60 syringes a month.
Ideally, use the syringe once. This minimizes the chances of infections that can be caused by a dirty needle. If you must reuse the syringe, use them only twice. The needles dull quickly because they are made to be used once. When they are dull, it is more uncomfortable for your cat that may make him resent the injection.
I Accidentally Bent the Needle On The Insulin Syringe – Can I bend It Back?
The insulin syringe needles are very fine and fragile. They will bend easily but don't bend them back. Because they are so thin, bending them back can create a weak s