Diabetes is not a standalone disease; there are several types that people may develop. Some types of this medical condition are more common than others. Good examples are diabetes insipidus and diabetes mellitus. You’ve probably heard a lot about mellitus, or maybe you or someone you know has it.

The more you know about different types of this metabolic disease, the easier it becomes to recognize their telltale signs and prevent potential complications. This article discusses diabetes insipidus vs. mellitus differences, their causes, symptoms, and treatments.

Why Both Insipidus And Mellitus Are Called Diabetes?

Besides diabetes insipidus vs. mellitus differences, they do have one major similarity – both conditions share the same word in their name.

The term diabetes has its roots in Greek and means "a siphon" or "to pass through." This name was given because the condition is characterized by increased urine output or frequent urination, which makes people with diabetes "pass through" larger volumes of urine. The words "mellitus" and "insipidus" are added to differentiate between the two types of diabetes and their respective causes or consequences.

More precisely, back in 1794, German physician Johann Peter Frank was the first to introduce[1] the term diabetes insipidus to establish differences between patients with this condition and those with diabetes mellitus.

What are the Symptoms of Diabetes Mellitus and Insipidus?

Both diabetes insipidus and mellitus have similar symptoms, but their causes are different. The most significant symptoms of each condition are listed below:

  • Exhaustion: In diabetes mellitus, exhaustion occurs when cells don’t use glucose for energy due to insulin resistance[2]. High blood sugar levels may lead to dehydration, which also causes fatigue. In diabetes insipidus, exhaustion results from the disruptive impact of excessive thirst and urination on sleep patterns.

  • Thirst: This is the hallmark symptom of both conditions. In diabetes mellitus, blood sugar is too high, which prompts kidneys to remove glucose through urine, and results in excessive thirst. This can also lead to dry mouth diabetes. In diabetes insipidus, thirst happens because the body is unable to properly conserve water due to hormonal imbalance.

  • Blurred vision: In diabetes mellitus, the changes in fluid levels within the eyes can lead to blurred vision. Moreover, diabetes can damage blood vessels in the retina and cause vision problems. Blurred vision is not such a common symptom in diabetes insipidus, but chronic dehydration can lead to dry eyes and temporary blurriness.

Unusual symptoms of diabetes are also worth remembering. These include periodontitis, skin changes, frequent infections, hearing changes, pain in your limbs, and nausea.


Are Diabetes Insipidus and Diabetes Mellitus The Same Thing?

No, diabetes insipidus is not the same thing as diabetes mellitus. Diabetes insipidus[3] is a disorder wherein the body produces too much urine because it is unable to balance fluid levels healthily. Most people produce one to three quarts of urine a day, but people with this disease make up to 20 quarts.

There are four types of diabetes insipidus: central or neurogenic, nephrogenic, dipsogenic due to dysfunctional thirst mechanism, and gestational.

On the flip side, diabetes mellitus is a condition where the body doesn’t produce enough insulin or doesn’t respond normally to it, which increases blood glucose (sugar) levels. There are two types of diabetes mellitus. They are type 1, where the pancreas doesn’t produce insulin because the immune system attacks pancreatic cells, and type 2 where the body produces lower amounts of insulin or is resistant to it.

How do Diabetes Insipidus and Diabetes Mellitus Differ?

Although they share a similar name, diabetes insipidus vs. mellitus differences are quite significant. They are explained below:

  • Hormones: The main hormone involved in diabetes mellitus is insulin. Sometimes the body doesn’t produce enough insulin[4] or becomes resistant to it. The main purpose of insulin is to regulate blood sugar by facilitating its uptake into cells for energy production. Without insulin, levels of blood sugar keep increasing. The main hormone involved in diabetes insipidus is antidiuretic hormone[5] (ADH) or vasopressin, which helps regulate the body’s water balance and controls the reabsorption of water by your kidneys. Low levels of ADH or the inability of kidneys to respond to this hormone leads to symptoms of diabetes insipidus.

  • High blood sugar levels: One of the biggest differences in diabetes insipidus vs. mellitus is that the latter involves high levels of blood sugar whereas in people with diabetes insipidus, they remain normal. Diabetes mellitus is characterized by persistently elevated blood sugar due to insufficient production of insulin or insulin resistance.

  • Health complications: People with diabetes mellitus are at a higher risk[6] of heart disease, kidney damage, eye damage, and lower extremity amputations. Health complications associated with diabetes insipidus include electrolyte imbalance, kidney dysfunction and failure, and dehydration. Not only can dehydration cause blood in urine, but it also leads to weakness and confusion.

Can You Have Diabetes Mellitus and Diabetes Insipidus at the Same Time?

Technically, it is possible to have both conditions at the same time, but it is unlikely. In one case report[7], a patient with type 2 diabetes mellitus with poor insulin control also developed diabetes insipidus.

Although it’s possible to develop both diseases, it’s not common. As seen above in diabetes insipidus vs. mellitus differences, these conditions have entirely different causes and mechanisms of action.

What are the 3 P’s of Diabetes?

Diabetes is a long-term and quite complicated condition. However, the main aspects of this condition are three P’s, and they are:

  • Polydipsia: excessive thirst, i.e., you may feel thirsty all the time and notice your mouth is dry.
  • Polyuria: excessive urination, i.e., refers to producing more than three liters of urine a day.
  • Polyphagia: excessive hunger, i.e., hunger that doesn’t go away after a meal. But is sweating after eating a sign of diabetes? Yes, sweating during or after eating is a sign of autonomic neuropathy in people with diabetes.

The Role of Insulin in 3 P’s

Insulin affects all of the three P’s described above. When it comes to excessive urination, lack of insulin or resistance to this hormone leads to elevated blood sugar, which pulls water along with it through osmosis[8]. As a result, the production of urine increases.

Insulin is involved in excessive thirst because increased urine production may lead to dehydration and thereby stimulate the thirst mechanism.

When there is not enough insulin in the body or the insulin is not working as it should, cells are unable to receive blood sugar for energy. This results in cells perceiving a shortage of energy, which in turn triggers hunger signals in the brain. This is the connection between insulin and excessive hunger.

How are Diabetes Insipidus and Mellitus Diagnosed?

Based on the symptoms you provide, the doctor will suspect you have one of these conditions, but they will order a few tests to rule out other potential diseases. Despite the diabetes insipidus vs. mellitus differences, their diagnostic process is quite similar. It includes the following:

  • Blood test: diagnosis of diabetes mellitus may involve several types of blood tests, including fasting glucose test, and the A1c or glycated hemoglobin test. For diabetes insipidus diagnosis, the doctor may order a blood test to evaluate your sodium levels.

  • Urinalysis: reveals how diluted or concentrated your urine is. You may need to collect urine for 24 hours to see how much your body produces during that timeframe.

  • Fluid deprivation test: you may need to do either a short-form or long-form test. In a short-form test, you stop drinking fluid, usually at dinnertime, and collect a urine sample in the morning. The long-form test requires a hospital stay where a doctor weighs you and obtains a urine sample every one to two hours. This test primarily determines what type of diabetes insipidus you may have.

Treatment of Diabetes Insipidus and Mellitus

Both diabetes insipidus and mellitus are chronic diseases, but it is possible to manage them and prevent complications.

Treatment for diabetes mellitus depends on the type, and it usually includes oral medications such as metformin and insulin therapy. Lifestyle modifications and regular blood sugar monitoring are also necessary alongside the management of complications. People with diabetes mellitus can strongly benefit from products such as Gluctose-blood sugar supplement. Regular intake of Gluctose boosts your energy levels, normalizes blood sugar and cholesterol, and improves your overall health.

Treatment for diabetes insipidus also depends on the type of condition you have. You may need desmopressin replacement therapy to address ADH deficiency. Other aspects of treatment include hydration management, monitoring and modifying fluid intake, and treating the underlying cause.


Is Type 2 diabetes mellitus or insipidus?

Type 2 diabetes is diabetes mellitus, not insipidus. While diabetes mellitus is associated with insulin resistance and high blood glucose levels, insipidus is indicated by a deficiency of antidiuretic hormone or the kidney’s ability to respond to this hormone.

What is another name for diabetes insipidus?

Another name for diabetes inspidus is arginine vasopressin deficiency or arginine vasopressin resistance.

Which hormone deficiency is responsible for diabetes insipidus?

Deficiency or the ineffective action of antidiuretic hormone or vasopressin is responsible for diabetes insipidus. Your hypothalamus produces antidiuretic hormone, and the pituitary gland releases it. The main function of this hormone is to regulate the amount of water your kidneys reabsorb, thus controlling the urine concentration and maintaining proper water balance in the body.


The main diabetes insipidus vs. mellitus differences are in the underlying cause or mechanism of action. Diabetes insipidus has nothing to do with insulin and blood glucose; it is associated with ADH deficiency and excessive urination. Diabetes mellitus is characterized by insufficient insulin production or resistance to this hormone, which leads to elevated blood sugar. While these conditions share some similarities, they have different triggers and affect your body differently.


1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9578068/
2] https://www.medicalnewstoday.com/articles/323398
3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4743391/
4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8232639/
5] https://www.webmd.com/a-to-z-guides/what-to-know-about-antidiuretic-hormone-adh
6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3870323/
7] https://pubmed.ncbi.nlm.nih.gov/29659364/
8] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5736956/

Amna Eltawil

Amna Eltawil

Amna Eltawil is an Egyptian journalist who grew up on the coast of the Mediterranean in Alexandria, Egypt, before moving to Cairo and getting her bachelor's in journalism. From there, she went on to cover new stories and entertainment news for several local and international platforms. Amna enjoys visiting cities on the Mediterranean reminiscent of her childhood city Alexandria, like Barcelona, and she can never have enough of Paris, where she simply likes to walk the streets of the city and enjoy a simple Parisian crepe or have a chill picnic.

Written by Amna Eltawil

More stories

Migraine & Headache Awareness Month 2024: Myth, Truth & Action

If you suffer from migraine or headache disorders, you’re already aware of the significant impact the symptoms can have on your daily life. However...

Anxiety Attack Vs Panic Attack - What is Difference

A lot of people may use the terms panic attack and anxiety attack interchangeably. While these two conditions may have similarities, one is entirel...