Diabetic Thirst: What Is It and How Can You Fix It?

Medically Reviewed by Michael Dansinger, MD on May 24, 2022
Written by Hope Cristol
4 min read

You drink plenty of water. You don’t eat a lot of salt. You’re not doing intense workouts. So why are you thirsty all the time? That’s a question you should ask your doctor -- right away.

Excessive thirst and a dry mouth are telltale signs of high blood sugar. You could have diabetes and not know it. If you’ve already been diagnosed, you might need to step up your treatment.

Other issues can also cause excessive thirst. But it’s important to diagnose diabetes early to lessen the chance of complications.

Excessive thirst in diabetes is called polydipsia. It’s common in both diabetes mellitus and diabetes insipidus.

Diabetes mellitus, which includes type 1 and type 2 diabetes, happens when your blood sugar is too high. Type 1 is an autoimmune disease that causes your pancreas to stop making insulin, a hormone that helps blood sugar get into your cells. In type 2, your body doesn’t make enough insulin or doesn’t use insulin well.

Diabetes insipidus does not relate to your blood sugar levels. It’s a rare disorder that affects your kidneys and the hormones that make them work properly. Diabetes insipidus causes your body to produce large amounts of urine, making you pee a lot, which dehydrates you.

Both high blood sugar and frequent urination can result in constant, severe thirst.

Insulin helps your body use sugar for energy. When you don’t have enough insulin, excess sugar (glucose) builds up in your blood.

Kidneys are your backup here. They work extra hard to absorb and filter that excess sugar.

They may also pass some of that sugar out of your body through urine. As that happens, it pulls fluids from your tissues, too. The process leaves you dehydrated and thirsty.

If you have a thirst that won’t go away no matter how much you drink, or you pee an unusual amount every day, you could have polydipsia. But don’t jump to conclusions about your diabetes status. Keep in mind that many medications can cause thirst and dry mouth, including:

In addition, dry mouth is a hallmark of conditions besides diabetes, including:

  • Salivary gland diseases
  • Sjogren’s syndrome
  • HIV/AIDS

Excessive thirst isn’t just annoying. It could lead to serious health issues.

Dehydration. Prolonged dehydration can cause nausea, dizziness, headaches, and fainting. Dehydration also causes you to pee less, which stops your body from getting rid of excess blood sugar through urine. When this happens, your blood sugar levels shoot up too fast.

Uncontrolled high blood sugar. Whether you have undiagnosed or poorly controlled diabetes, high blood sugar puts your whole body at risk. Managing diabetes means lowering your risk of complications such as:

If diabetes is the cause of your excessive thirst, getting it under control is the first step to relief. That starts with a diagnosis, followed by a diabetes treatment plan.

Medicines to control blood sugar. Different types of diabetes call for different treatments.

In type 1, you’ll need to take insulin several times a day or use an insulin pump, which delivers steady doses throughout the day. In type 2, you may need medicine if diet and exercise aren’t enough. Type 2 diabetes drugs include insulin and metformin, among others.

Surgery. If you’re obese (very overweight) and have type 2 diabetes, you might consider weight loss surgery. It can help you lose a lot of weight, get to a normal blood sugar level, and possibly ditch your diabetes medicine.

Lifestyle changes. Eating healthy foods and exercising every day can improve just about every aspect of your health, including diabetes. A dietitian or diabetes educator can help you develop a healthy eating plan that helps you track carbohydrates, which impact your blood sugar more than protein or fat do. If you smoke, make it a priority to quit.

Dry mouth relief. While you work to rein in your diabetes, you can try short-term strategies to relieve your dry mouth.