Join Our Thyroid Awareness Campaign this January!

January is Thyroid Awareness Month

Join us this January to spotlight thyroid health. Participate, share, and spread awareness for a chance to win exciting prizes!

Hypothyroidism and Dehydration

Learn about dehydration and how it impacts your thyroid function.
Hypothyroidism and Dehydration
Last updated:
Medically Reviewed by:

In this article

Do you have enough thyroid hormone? If not, you could be hypothyroid. Do you drink enough water? If not, you could be dehydrated. Seems straightforward. But while hypothyroidism and dehydration may seem unrelated, they can actually exacerbate each other’s effects, leading to a range of symptoms and complications. In this article, we’ll explore the relationship between hypothyroidism and dehydration, including the symptoms to watch out for, the underlying causes, and effective strategies for managing and preventing these conditions. By understanding the interplay between these two factors, you can take proactive steps to protect your health and improve your overall well-being.

Your thyroid gland is located at the bottom of your neck and produces hormones crucial for regulating your body’s metabolism. Thyroid hormones – thyroxine (T4) and triiodothyronine (T3) – influence energy production, body temperature, heart rate, and more.  An imbalance of thyroid hormone levels can lead to various health issues, including hypothyroidism – thyroid hormone levels that are too low. While many factors can trigger or contribute to thyroid dysfunction, one that is often overlooked is dehydration. Ahead, we will explore the complex relationship between dehydration and hypothyroidism. 

The importance of staying hydrated

First, it’s helpful to know why staying hydrated is so important.

Water is integral to our physiology, and about 60% of the body is water. This water is essential for:

  • Maintaining your body temperature
  • Lubricating joints and cushioning them
  • Protecting your spinal cord and other tissues
  • Getting rid of waste products through your urine, bowel movements, or sweat

Water helps keep your body functioning, and without enough water, health issues may arise.

What is dehydration?

Dehydration occurs when your body loses more water than you take in.

Dehydration can be caused by various factors, including inadequate fluid intake, excessive sweating, vomiting, diarrhea, and certain medical conditions such as diabetes or kidney disease. Insufficient fluid intake is one of the leading causes of dehydration, as not consuming enough liquids throughout the day can lead to an imbalance between the amount of water leaving the body and the amount being taken in. Furthermore, activities that cause excessive sweating, such as prolonged physical exercise or being in a hot environment, can also contribute to dehydration by depleting the body’s water stores. Additionally, conditions that result in frequent vomiting or diarrhea can lead to dehydration as the body loses significant amounts of water and electrolytes. It is important to note that certain medical conditions like diabetes or kidney disease can affect the body’s ability to retain water, leading to an increased risk of dehydration.

Signs and symptoms of dehydration include the following:

  • Dark-colored urine
  • Dizziness
  • Fatigue
  • Lightheadedness
  • Dry mouth, sticky saliva
  • Dry skin
  • Fatigue
  • Feeling thirsty
  • Urinating less often or in low amounts

Symptoms can range from mild to severe, depending on how dehydrated you are. Sometimes, dehydration can be so severe it is life-threatening. Signs and symptoms of severe dehydration include

  • Confusion
  • Fainting
  • Rapid breathing 
  • Rapid heartbeat

You should seek immediate medical attention if you experience any of these symptoms.

How dehydration alters thyroid hormone levels

There are three key reasons experts believe dehydration affects your thyroid hormone levels.

Altered hormone transport

When you become dehydrated, the amount of water in your body decreases. Because of this, you can develop a medical condition called hypovolemia, with a decrease in your blood plasma volume.  

In turn, the cells and proteins in your blood become more concentrated, meaning there are more of them in a smaller volume. This is called hemoconcentration.

When hemoconcentration occurs, thyroid hormone transport proteins become more concentrated in the blood. Thyroid hormone transport proteins include thyroxine-binding globulin, albumin, and prealbumin. When thyroid hormone binds to these transport proteins, they become inactive, meaning your cells can’t use them. So, more transport proteins in a smaller volume may lead to more thyroid hormone binding. This may lower the amount of free (active) thyroid hormone available for your cells. As a result, thyroid biomarkers - T4, T3, and thyroid-stimulating hormone (TSH) - may point towards a thyroid disorder.

A small 2007 study examined how mild to moderate dehydration affects thyroid function biomarkers in older individuals without any history of thyroid disease. It showed that biomarkers for thyroid function were elevated upon admission to the hospital for dehydration. Fluid volume status biomarkers, including albumin, were also elevated.

Reduced blood flow

Iodine is an essential nutrient that your thyroid needs to make thyroid hormone. After eating, your GI system breaks down the food and transports essential nutrients like iodine through your bloodstream to cells that need them. However, when you are dehydrated and hypovolemia ensues, your body changes the amount of blood flow to your organs.

To compensate for a lower blood volume, your body ensures your liver, heart, and skeletal muscles have enough blood to function. This means the blood supply to your thyroid decreases. As a result, iodine transport to your thyroid may reduce, further affecting how much thyroid hormone it can make.

Increased histamine levels

Histamine is a chemical that is part of your immune system. Most know histamine as the cause of allergy symptoms such as itchy eyes or a runny nose.  When you become dehydrated, your body releases histamine. Due to the histamine release, you can develop symptoms of high histamine levels, including:

  • Fatigue
  • Dry skin and hair
  • Temperature sensitivity, especially to extreme changes
  • Mental health changes
  • Difficulty thinking or concentrating

These symptoms are very similar to what you see in those with untreated or undertreated hypothyroidism. Therefore, dehydration can cause hypothyroidism-like symptoms or make current hypothyroidism symptoms worse.

Will drinking water correct underlying thyroid dysfunction?

The short answer is yes if the cause is dehydration.

The same 2007 study mentioned above showed that thyroid function biomarkers, including total and free T4 and T3, returned to more normal levels with rehydration intravenous (IV) fluids within 48 to 72 hours. As long as the individuals stayed hydrated, their thyroid biomarkers remained within the reference range when retested three months later.

Now, suppose the cause of your thyroid dysfunction is not related to dehydration, such as thyroidectomy (removal of all or part of your thyroid gland) or Hashimoto’s (autoimmune thyroid disorder). In that case, drinking water will not correct your thyroid dysfunction. However, it may help prevent the exaggeration of thyroid symptoms by preventing histamine release or improve your overall health, as water is essential for our bodies.

How much water do I need?

Believe it or not, there is no set recommended amount of water that applies to everyone. However, a general guideline that is often recommended is to consume at least eight glasses of water, which is about 64 ounces or 1.9 liters. This is known as the “8x8 rule.” It is important to note that your individual needs may differ, and it is vital to listen to your body and drink water when thirsty. Your hydration needs will vary based on your age, sex, and lifestyle. Those who live in hot climates, are physically active, have diarrhea or vomiting, or are pregnant usually have a higher water need.

Tips for preventing dehydration

The number one way to prevent dehydration - you probably can guess it - is drinking plain water.

Many find it hard to drink water throughout the day. Here are tips from the Centers for Disease Control and Prevention (CDC) on increasing your water intake and staying hydrated.

  • Carry a reusable water bottle and fill it up as needed.
  • Serve water at meal times.
  • Add lemon, limes, or other fruits to your water to help improve the taste.
  • Choose plain water over sugary drinks such as sodas or juices and sports replacement drinks.
  • Avoid drinking too many caffeinated beverages, as they can cause dehydration.

You can also increase your water intake by eating fruits and vegetables with a high water content, like watermelon or cucumbers.

Here are some other ways to prevent dehydration.

Drink when you’re thirsty and even when you’re not: Thirst is your body’s way of signaling its need for hydration. Trust your body’s signals and drink water when you feel thirsty. But you should also keep track and ensure that you get sufficient daily intake even if you’re not thirsty. 

Monitor your urine color: Your urine color can indicate your hydration levels. Aim for a pale, straw-like color. Dark urine may indicate that you need to increase your water intake.

Consider electrolyte balance: If you’re engaging in intense physical activity or sweating profusely, replenishing electrolytes through sports drinks or electrolyte-rich foods can help maintain proper hydration levels.

Can you drink too much water?

Water is essential for our survival. It plays a crucial role in maintaining bodily functions, aiding digestion, and regulating body temperature. We’re often told to drink plenty of water daily to stay hydrated, but can we ever have too much of a good thing? Surprisingly, the answer is yes. While rare, it is possible to drink too much water, resulting in water intoxication and hyponatremia in its more severe form.

Water intoxication and hyponatremia occur when there is an imbalance of electrolytes – in particular, sodium – in the body, primarily caused by drinking excessive water in a short period. This condition is more common in certain situations, such as endurance sports or extreme physical activities that cause excessive sweating. Athletes who drink excessive amounts of water without replenishing vital electrolytes can be at risk of water intoxication.

Sodium is an essential electrolyte that helps regulate the balance of fluids in the body and is crucial for nerve and muscle function. When the sodium levels in the blood become too diluted due to excessive water consumption, it can lead to various symptoms such as nausea, headache, confusion, seizures, and, in severe cases, even coma. In extreme cases, it can be life-threatening. Treatment typically involves addressing the underlying cause and restoring sodium balance through dietary changes, medication, or intravenous fluids. If you suspect water intoxication or hyponatremia, it’s crucial to seek medical attention immediately.

So, how much water is too much? A 2013 study reported that the kidneys can eliminate about 20 to 28 liters of water daily, but they can eliminate no more than 0.8 to 1.0 liters every hour. So, to avoid water intoxication and hyponatremia, you should avoid drinking more than about 1 liter of fluid per hour.

Generally, it is recommended to drink around eight glasses of water a day, which is about two liters or half a gallon. However, this general guideline can vary depending on factors such as age, weight, activity level, and climate. It’s important to listen to your body’s signals and hydrate accordingly. If you’re unsure how much water you need, consulting a healthcare professional can provide personalized guidance.

It is important to note that hyponatremia is relatively rare, and most people can maintain a healthy balance of fluids and electrolytes by drinking water in moderation and listening to their body’s thirst signals.

A note from Paloma Health

Many factors can influence your thyroid function, and staying on top of an underactive thyroid can be complicated. But Paloma Health makes it easier with virtual thyroid care from top thyroid experts and easy at-home blood testing. Paloma’s at-home testing kit only requires a finger-pick blood sample to measure how well your thyroid functions. Our testing kit measures the three most common thyroid biomarkers to diagnose a thyroid disorder. It also measures thyroid antibodies, which signal whether you have an autoimmune thyroid condition. Order your kit today to start your journey to a healthier you. And don’t forget to drink your water!


Centers for Disease Control and Prevention. Water and healthier drinks. Centers for Disease Control and Prevention. Published October 12, 2020. Accessed October 9, 2023.

Medline Plus. Dehydration. Published 2019. Accessed October 9, 2023

Ybarra J, Fernandez S. Rapid and reversible alterations in thyroid function tests in dehydrated patients. Nurs Clin North Am. 2007;42(1):127-34, viii-ix. doi:

Kim KB, Kwak YS. Dehydration affects exercise-induced asthma and anaphylaxis. J Exerc Rehabil. 2019 Oct 28;15(5):647-650. doi:

Joo MA, Kim EY. Hyponatremia caused by excessive intake of water as a form of child abuse. Annals of Pediatric Endocrinology & Metabolism. 2013;18(2):95. doi:

Share article:

Emilie White, PharmD

Clinical Pharmacist and Medical Blogger

Emilie White, PharmD is a clinical pharmacist with over a decade of providing direct patient care to those hospitalized. She received her Doctor of Pharmacy degree from Massachusetts College of Pharmacy and Health Sciences. After graduation, Emilie completed a postgraduate pharmacy residency at Bon Secours Memorial Regional Medical Center in Virginia. Her background includes caring for critical care, internal medicine, and surgical patients.

Read more

Is Paloma Right For Me?

Hypothyroidism is a long-term commitment and we’re committed to you. Schedule a free, no-obligation phone consultation with one of our intake specialists to find out more.

Schedule a call
thyroid hormone for hypothyroidism

Find out if Paloma is right for you. Schedule a free call with one of our health care advisors.

Schedule a Call