In August 2026 the American Animal Hospital Association published its first new diabetes guideline for dogs since 2018. The sections are free to read on its website, but they are written for vets. This page is the same guideline written for the person holding the syringe: what the disease is, how it is found, what the vet is aiming for, which insulins exist, what to feed, what the checkups are for, what to do when the sugar goes too low, and what it costs. Every number is quoted from the guideline or from the document named under it.
If you read nothing else, read this. The guideline puts one sentence above everything:
The primary goal of treating canine diabetes mellitus is to control clinical signs.
Not a perfect blood sugar. Not a number on a meter. A dog that has stopped drinking and peeing too much, stopped eating like it is starving, and stopped losing weight. The guideline says in so many words that a well-controlled dog will still have high readings sometimes: "Occasional brief periods of significant hyperglycemia (>300 mg/dL) are expected in patients with good clinical control and do not require additional workup." Owners who do not know this spend the first months frightened by numbers the vet is not worried about.
A dog's diabetes is the kind where the pancreas has stopped making insulin. The guideline's opening line is "Dogs develop a form of DM characterized by an absolute insulin deficiency from permanent beta cell loss." DM is diabetes mellitus, the disease's full name, and the guideline uses the short form throughout. That is why a diabetic dog needs insulin injections, and why it is usually for life. The Merck Veterinary Manual puts the contrast with cats plainly: "Remission is possible in cats; in dogs the disease, in the absence of a predisposing disease, is generally lifelong."
The pill you may have read about is for cats. The FDA approved Bexacat in December 2022 as "the first oral new animal drug to improve glycemic control in otherwise healthy cats with diabetes mellitus not previously treated with insulin", and its own announcement says "An SGLT2 inhibitor is not insulin and is not for use in cats with the type of diabetes mellitus that requires insulin treatment." Every diabetic dog has that type. The guideline's first takeaway on treatment is "All diabetic dogs are insulin deficient and require exogenous insulin therapy."
It is a disease of middle age and later. The guideline names Australian terriers, beagles, Samoyeds and keeshonden as breeds that are more susceptible. One careful count comes from VetCompass, which read the records of first-opinion practices in the UK and found 439 cases, "giving an apparent prevalence of 0.34%", which is about one dog in three hundred. In that study "Yorkshire terriers had increased odds, whereas German shepherd dogs and golden retrievers had lower odds of DM", and being overweight, having pancreatitis, Cushing's disease or a urinary infection all went with it. Merck's owner edition says middle-aged dogs are affected most often, "with females affected twice as often as males", and VetCompass found that "Neutered males were at an increased risk of diabetes compared to entire males, whereas neutering was not associated with DM in females."
There is one exception to "for life", and it matters if your dog is an unspayed female. Each heat is followed by about nine weeks of high progesterone, which drives a hormone that blocks insulin, and in some dogs that tips into diabetes. The guideline says "Prompt ovariectomy results in a rapid decline in growth hormone and may allow some dogs to undergo diabetic remission." Spaying soon after diagnosis is therefore part of the treatment for an intact female, not an optional extra, and the guideline adds that anesthesia "is not contraindicated in otherwise healthy, stable, nonketoacidotic diabetic patients."
Sugar spills into the urine once the blood level passes the kidney's limit, and the guideline gives that limit: "The average canine renal threshold for glucose is 160–200 mg/dL, so expect polyuria (PU) and polydipsia (PD) when the blood glucose (BG) exceeds this range." Polyuria is peeing a lot; polydipsia is drinking a lot. The sugar pulls water out with it, the dog drinks to keep up, and because the body cannot use the sugar it is eating, the dog is hungry and losing weight at the same time. Those four things, drinking, peeing, eating and losing weight, are the disease. The drinking page gives the amounts that count as normal and how to measure a day's intake at home, which is the one sign you can put a number on.
Dogs do not have a long quiet lead-up. "Absolute insulin deficiency predictably results in ketosis within several days, so most dogs have a relatively short period of clinical signs before presentation." A dog that has been drinking heavily for a couple of weeks should be seen this week, not next month. If it is also flat, off its food or vomiting, or its breath has turned sweet, it is today: those are the signs of ketoacidosis, which is on the emergencies page.
Some dogs are diagnosed because an owner noticed the eyes turning cloudy. Sugar gets into the lens and pulls water in after it, and the lens goes white. A study that followed 200 diabetic dogs through the records of a university hospital found that "half of the population had developed cataracts by the 170th day postdiagnosis of diabetes mellitus, while 75% and 80% of the population developed cataracts by 370 days and 470 days, respectively." That is most dogs within six months and four in five within sixteen. Merck notes that cataracts "develop frequently in dogs (but not cats) with poorly controlled diabetes mellitus", and good control helps, but the 200-dog figures are for diabetic dogs in general, not only the badly controlled ones. Diabetic cataracts can be removed surgically by a specialist, and the guideline says that with the short course of steroid eye drops around that surgery "the insulin dose does not usually need to be changed". Ask about the eyes at diagnosis so the change is not a shock.
The diagnosis itself is quick. "Documenting glucosuria and concurrent hyperglycemia in a dog exhibiting characteristic clinical signs quickly establishes a DM diagnosis." The guideline uses the international ALIVE definition: a blood glucose of 200 mg/dL or more, fasted or not, plus sugar in the urine, plus the classic signs with no other explanation. Unlike cats, dogs do not get badly fooled by the stress of the visit; the guideline lists stress as "Mild in canines, lasts 4-6 hr."
The first visit usually costs more than the diagnosis because the vet is also looking for what else is going on. The guideline lists the tests in order of importance: a chemistry panel (expects high sugar, often high cholesterol and triglycerides, often a raised liver enzyme called ALP, which is expected in a new diabetic and does not by itself point to Cushing's disease), a urinalysis, a urine culture only "in patients with signs of urinary tract infection or an active urine sediment", a pancreatitis test "not required unless clinical signs of pancreatitis are present", a blood count, and a thyroid test that "the task force does not recommend" as routine, because untreated diabetes pushes the thyroid number down on its own. If the estimate lists a thyroid panel or a pancreatitis test, it is fair to ask what sign prompted it. The vet bill page explains what each line is.
This is the part of the guideline every owner should have in writing, because it decides what you are working toward and what you can stop worrying about.
Diabetes is considered well controlled if the patient does not exhibit polyuria, polydipsia, or polyphagia, and body weight is stable or increasing.
Drinking normal, peeing normal, appetite normal, weight steady. That is the whole definition. The monitoring section says the same thing from the other direction: "The goal is not tight BG control, but to maximize the amount of time the BG is below the renal threshold for glucosuria while avoiding hypoglycemia." The overview explains why a dog can live with readings a human diabetic could not: "Most dogs tolerate short periods of moderate hyperglycemia (BG >180 mg/dL) as long as the dog spends most of the day below this range and clinical signs are controlled. This mild elevation in dogs does not seem to lead to retinopathy, strokes, and other complications as it can in humans after decades of hyperglycemia." BG is blood glucose, the sugar reading, and the guideline gives every figure in milligrams per deciliter, the unit US meters use.
So the two dangers are not symmetrical. Sugar that runs a little high costs a diabetic dog very little. Sugar that goes too low can kill it in an afternoon; the Vetsulin label says "Overdosage can result in profound hypoglycemia and death." Every rule in the guideline about doses leans the same way: "Empower clients to decrease or skip an insulin dose if clinical hypoglycemia is noted and/or confirmed on a veterinary-calibrated PBGM but emphasize that they should never increase the dose or frequency of insulin administration without clear instructions from their veterinarian." A PBGM is a handheld blood glucose meter made for animals.
The guideline is also candid about the meter itself. "Spot-checking BG is unreliable", and on what the numbers are for: "the presence or absence of clinical signs is often a more accurate marker of DM control than any glycemic data obtained." The resource page on reading glucose curves opens with "clinical signs supersede all else." If your dog is bright, drinking normally and holding its weight, a single high reading on a Tuesday is not a reason to change anything.
Insulin is started on the day of diagnosis. The dose is worked out per kilogram of the dog's ideal weight, not its current weight, and rounded down: "calculate the insulin dose based on the dog's estimated ideal body weight and to round down to the nearest whole U." The task force's first choices are "Either U-40 porcine insulin zinc suspension (Vetsulin) or U-100 neutral protamine Hagedorn (NPH)", both "using a starting dose of 0.25–0.5 U/kg every 12 hr", and where most dogs end up: "Most dogs are well controlled on insulin at an average dose of 0.5 U/kg every 12 hr (range of 0.2–1.0 U/kg every 12 hr)." A 44-pound dog (20 kg) at 0.5 units per kilogram is 10 units twice a day; the starting dose would be 5 to 10 units. The guideline's Table 4.1 is the source for the table below.
| Insulin | Strength and FDA status for dogs | Starting dose in the guideline | What the guideline says |
|---|---|---|---|
| Porcine lente Vetsulin (Merck Animal Health) | U-40. Approved for dogs since 2004. | 0.25 to 0.5 U/kg every 12 hours; the label says 0.5 U/kg once a day | A first-choice option. Pens in half-unit or one-unit steps. Must be shaken until uniformly milky. Peak 1 to 10 hours, lasts 10 to 24 hours. |
| NPH Novolin N (Novo Nordisk), Humulin N (Lilly) | U-100. A human insulin, not approved for dogs. | 0.25 to 0.5 U/kg every 12 hours | A first-choice option. "ReliOn-N is the Walmart-dispensed form of Novolin-N." Lower end of the dose for big dogs, higher end for small ones. Peak 0.5 to 8.5 hours, lasts 4 to 10 hours. |
| PZI ProZinc (Boehringer Ingelheim) | U-40. Approved for dogs since 2019. | 0.25 to 0.5 U/kg every 12 hours; the label says 0.5 to 1 U/kg once a day | "Once-daily dosing in dogs is FDA approved." Can last a long time in dogs, so the guideline wants once-daily starts or a sensor on the dog at first to avoid lows. Peak 8 to 12 hours. |
| Glargine U-100 Lantus, Basaglar, Semglee, Rezvoglar | U-100. A human insulin, not approved for dogs. | 0.25 to 0.5 U/kg every 12 hours | "Potential option in dogs." Peak 6 to 10 hours, lasts 12 to 20 hours. |
| Degludec Tresiba (Novo Nordisk) | U-100, U-200 pen. A human insulin, not approved for dogs. | 0.5 U/kg once a day | Peakless. "Can be considered as a first option insulin in dogs." Does not need to be given with a meal. Some dogs still need it twice a day. The U-200 pen moves in two-unit steps, so it suits large dogs. |
| Glargine U-300 Toujeo (Sanofi) | Pen, one-unit steps. A human insulin, not approved for dogs. | 0.5 U/kg once a day | Peakless. "Can be considered as a first option insulin in dogs." Does not need to be given with a meal. Some dogs still need it twice a day. |
Two of those are approved for dogs by the FDA and the rest are human insulins prescribed off label, which is legal and common. When ProZinc was approved for dogs the FDA said the common side effects in the trial "were lethargy, anorexia, hypoglycemia, vomiting, seizures, shaking, diarrhea, and ataxia", and it warned against "unapproved, compounded insulin products, which have not been evaluated for safety and effectiveness." The two approved products each have a page here, written from the label: Vetsulin and ProZinc.
The newest change in the guideline is the two "peakless" insulins at the bottom of the table, degludec and glargine U-300. They release slowly and evenly, which is why they can often be given once a day and why "Basal insulins do not have to be timed with feeding and are less likely to induce hypoglycemia when meals are missed." In the studies the guideline cites, about 84% of dogs on degludec and 60% on glargine U-300 stayed on once-daily dosing. For a dog with an unreliable appetite, or a household that cannot hit the same two times every day, they are worth asking about. The guideline wants a glucose sensor on the dog when one of them is started, because it cannot be known in advance whether the dog will need it once or twice a day.
This is the mechanical mistake the guideline checks for first whenever a dog is not doing well. U-40 insulin has 40 units in a milliliter; U-100 has 100. The markings on a U-40 syringe and a U-100 syringe are different, so drawing "10 units" of Vetsulin into a U-100 syringe gives the dog 4 units, and the other way around gives it 25. The Vetsulin label says it in capitals: "USE OF A SYRINGE OTHER THAN A U-40 SYRINGE WILL RESULT IN INCORRECT DOSING." If a pharmacy or a website sells you syringes, the number on the box has to match the number on the bottle. For dogs on fewer than 5 units a dose the guideline also prefers the small 0.3 or 0.5 mL syringes "for accuracy": the marks are farther apart and easier to read.
Vetsulin is a suspension and has to be shaken "until a homogeneous, uniformly milky suspension is obtained." The others are the opposite: "roll but do not shake the vial." All of them live in the refrigerator; the Vetsulin label says "Store in an upright position under refrigeration at 2°C to 8°C (36°F to 46°F). Do not freeze." The label also says "Use contents within 42 days of first puncture", and here the guideline takes a more relaxed position than the labels do: "When insulin is refrigerated and handled carefully, the task force is comfortable with clients continuing to use insulin beyond the manufacturer recommended in-use duration (28–56 days for most insulin types)." That is a conversation to have with your own vet, not a decision to make alone, and the guideline draws the line hard on appearance: "If the insulin ever appears flocculent, discolored, or exhibits consistency changes, it should be replaced immediately." Flocculent means clumps or strands floating in it.
For the ordinary twice-a-day insulins the injection follows the meal, never precedes it, and the guideline gives the rule for a dog that does not finish: "If less than 50% of the meal is eaten, one-half of their normal insulin dose should be administered, and the dog should not be offered any additional food or treats until the next scheduled mealtime." If the dog leaves more than half of two meals in a row, call the vet. The schedule is meant to be livable: "clients should be allowed flexibility within a 2-hr window on each side of the normal dosing/feeding time with occasional missed or off-schedule doses considered acceptable." A missed dose is a phone call, not a catastrophe. A doubled dose to make up for it is the catastrophe. Never give a second injection because you are not sure the first one went in.
There is no magic diabetic food, and the guideline says so: "Dogs with DM can do well on any diet that is complete and balanced, fed at consistent times and in appropriate portions, and has palatability that supports a consistent appetite." The last clause matters more than the first two. A dog that eats its whole meal at the same time every day is easier to dose than a dog on a prescription diet it picks at.
What the diet is for is "to achieve or maintain an ideal body weight and assist with reducing postprandial hyperglycemia", the sugar spike after a meal. The guideline prefers canned to dry for that, because canned food has "fewer simple carbohydrates, higher water content, and less caloric density", and it likes fiber, which slows the spike. If the dog is on an ordinary food, it suggests "supplementing with canned pumpkin, green beans, or commercial fiber supplements containing psyllium or wheat dextrin." A walk after meals "may decrease postprandial hyperglycemia" too.
Weight is the number the guideline cares about most, and it wants it measured properly: "Measure body weight (using the same scale) and assess body condition score (BCS) and muscle condition score (MCS) (using the same scoring systems) at least once or twice monthly." Treats count in full: "Include the kilocalorie (kcal) contribution of any daily treats or snacks when calculating a patient's total daily caloric intake." If the dog is overweight, the loss is meant to be slow, "1–2% weight reduction/wk", and "Active weight loss should not exceed 2% of body weight per week." If the dog is thin, the advice flips: feed "a high-quality maintenance diet or a diabetic diet that contains soluble and insoluble fiber but is not designed for weight loss", because weight-loss foods are too low in calories to rebuild a dog that has wasted. The body condition scorer walks you through the hands-on check, and the calorie calculator turns the target into cups of your own food.
The first weeks are the busy ones. The guideline's own schedule:
A curve is a day of readings taken every two hours after the morning injection, and a sensor is a coin-sized patch on the skin that reads on its own for up to two weeks. Both, the meter to use, what the numbers mean, and the guideline's fixed order of things to check when a dog is not getting better, are on the monitoring page. The dose steps the guideline uses are small ones: in a dog that still has signs and a curve that never gets low enough, "0.5-1 U/dose in small to medium-sized dogs" or "1-2 U/dose in medium to large breed dogs", then another curve. Big jumps are how dogs end up with the emergency below.
Too much insulin for the food in the dog is the one emergency that happens at home, and the guideline wants every owner taught it on day one. The signs are "lethargy, sleepiness, strange behavior, abnormal gait, weakness, tremors, collapse, and seizures." A diabetic dog that is suddenly wobbly, glassy or oddly quiet is low until proven otherwise.
Keep corn syrup and a few cotton swabs where the insulin is, and make sure everyone who might be alone with the dog knows where they are. What happens afterward, why the dose comes down, and the other emergency, ketoacidosis, are on the emergencies page.
The guideline tells vets to say at the start that managing a diabetic dog "requires both time and financial commitment", and to say in the same breath that "over time the disease will be controlled in most dogs and proper treatment and monitoring often results in a good quality of life." The money is a diagnosis, a few weeks of curves and rechecks, then insulin, syringes, a meter or sensors, and the twice-yearly bloodwork, for the rest of the dog's life.
CareCredit publishes two sets of figures from a 2025 cost study. Its page on dog owners' biggest expenses says "the average cost of a test to diagnose diabetes is $365, and this may be followed by monthly diabetes maintenance, with average costs of $255 for a small dog or $287 for a large dog." Its diabetes page, dated April 2026, prices the insulin itself: a vial "is $79, but the cost can range from $62 to $143 depending on the brand of the insulin and the size of your dog", and says a vial typically lasts 40 to 80 days. Two things bring the number down. The guideline's own table notes that "ReliOn-N is the Walmart-dispensed form of Novolin-N", the human NPH insulin the task force lists as a first choice, which is a change of product and syringe to make with the vet, not on your own. And the VetCompass study found that among diabetic dogs "insured and neutered dogs had a lower hazard" of death, which probably says more about being able to keep paying for treatment than about any policy. Insurance has to be in place before the diagnosis; the insurance page shows which policies name diabetes as a permanent pre-existing condition, and the vet costs page has the wider numbers.
Write the answers down. The guideline expects the disease to be controlled in most dogs and puts the outlook in one sentence: "Prognosis for dogs with DM is favorable with proper treatment and monitoring." The dog does not know it has diabetes. It knows whether it feels well, whether dinner comes at the same time, and whether the person with the syringe is calm.
Cats get a different kind of diabetes, with two medicines given by mouth and a chance of remission. It has a page of its own: What does diabetes mean for my cat?