Reading time: 10 min.
Can Dehydration Cause Hair Loss? Understanding Dehydrated Hair
Dr. Umear Ahmad (GMC)
Medically reviewed by
Dr. Umear Ahmad (GMC)
Updated on September 22, 2024

Around 60% of the human body is made up of water [1], and everyone knows water is essential to life. Not drinking enough fluids can cause a wide range of health symptoms, but can dehydration cause hair loss

Well-known brands sell a huge range of products focused on adding moisture to tresses and preventing hair loss. While dehydration isn’t usually the main cause of hair loss or dehydrated hair, it can be a contributing factor. In this article, we’ll explore:

  • What dehydration is and how it contributes to hair loss
  • Symptoms of dehydration and tips to stay hydrated
  • Causes of dehydrated hair 
Table of Contents

What is dehydration?

In simple terms, dehydration occurs when the body loses more water than it takes in. This causes a fluid imbalance, which affects normal body processes, such as kidney and brain function [2]. 

Dehydration can be caused by not drinking enough fluids or by excessive water loss through sweating, urination, vomiting, or diarrhoea. You’re more likely to get dehydrated during very hot weather or during intense exercise. 

People taking certain medications, such as diuretics or laxatives, are more likely to become dehydrated. Some medical conditions can also put you at a higher risk, including diabetes [3].

Dehydrated man with hair loss

Common symptoms of dehydration include a dry mouth, lightheadedness, headache, and fatigue. If dehydration becomes more severe, you may develop a higher heart rate, low blood pressure, and you might become confused [4]. 

Can dehydration cause hair loss? 

At present, there is no research specifically on hair loss and dehydration. However, research on surrounding topics gives us some clues that dehydration may cause hair loss. 

Dehydration causes oxidative stress

Research shows your body releases more of a hormone called vasopressin when you’re dehydrated. Increased vasopressin triggers harmful oxidative stress, damaging cells and tissues [5]. 

Oxidative stress has been identified as playing a key role in the ageing process of hair [6]. Oxidative stress increases in the body as we get older, damaging hair follicle cells, which causes hair greying, slower hair growth, and hair loss [6]. 

  • A 2015 in-vitro (laboratory-conducted) study suggests that oxidative stress may be linked to androgenetic alopecia (male or female pattern baldness) [7]. 
  • A study from 2019 with 140 participants suggests oxidative stress is closely linked to a type of temporary hair loss called telogen effluvium [7]. 
  • A 2016 study with 63 participants found increased oxidative stress in younger patients with early-onset male pattern baldness [8].
  • A 2016 study with 52 participants found markers of increased oxidative stress in patients with androgenetic alopecia [9].

In vitro research does not always translate to real-life findings, and the studies had small sample sizes. However, if dehydration increases oxidative stress, and oxidative stress can cause some types of alopecia, that suggests that dehydration may indirectly be linked to hair loss. If you have hair loss, there’s likely to be another main cause. 

Symptoms of dehydration

Hydration affects blood flow

While there are no specific studies on dehydration and hair loss, water is important for healthy hair. Drinking enough water improves blood circulation in your body [10], which helps with transporting nutrients to hair follicles. 

When you’re dehydrated, you may have limited blood vessel function and higher blood pressure [10]. This can have a negative impact on your heart health by increasing nerve activity and reducing blood flow [10], limiting your supply of nutrients to hair follicles. 

Water is an important part of hair 

Water content plays an important role in the appearance and general health of your hair [11]. Water makes up around 15% of human hair [12], so drinking enough water to keep this topped up is essential. It’s also best to steer clear of chemical treatments, which can damage your hair fibres and reduce their water content [13].

Hydration affects scalp health

How much water you drink affects skin health, including the skin on your scalp. 64% of your skin [14] is made up of water, which helps it to act as a protective barrier against infections. 

Drinking plenty of water can improve skin health and elasticity [15], and you’re less likely to experience flare-ups of conditions like seborrheic dermatitis when your skin is well-hydrated [16]. As conditions like seborrheic dermatitis can cause hair loss [17], staying hydrated can indirectly protect you against hair loss by reducing your risk of flare-ups. 

Woman with dehydrated hair

What else may be causing your hair loss?

Dehydration is not the most common cause of hair loss. If you’re looking for the reason your hair is falling out, one of these other conditions may be behind it. 

Male or female pattern baldness

Androgenetic alopecia, known as male or female pattern baldness, is the most common cause of hair loss. It affects up to 50% of women and 80% of men at some point in their life [18]. 

Men often experience temple hair loss and a receding hairline, progressing to a bald spot on the crown, loss of hair on top of the head and, in some cases, complete baldness. Women are more likely to experience diffuse thinning

Hair loss from alopecia areata
Hair loss from alopecia areata

Autoimmune conditions

Autoimmune conditions like alopecia areata, lupus, and Hashimoto’s disease can cause hair loss. In these conditions, white blood cells attack hair follicles, damaging them and leading to hair shedding

Stress and anxiety

Stress and anxiety can contribute to hair loss by worsening androgenetic alopecia or triggering telogen effluvium [19]. Telogen effluvium causes hair to temporarily enter the resting (telogen) phase of the hair growth cycle, causing shedding. The diagram below shows the different phases of the hair growth cycle. 

hair growth cycle

Hormonal changes

Menopause, pregnancy, thyroid disorders and other hormonal imbalances can lead to hair loss [20]. Hormonal conditions like polycystic ovary syndrome (PCOS) can cause hair loss in some women but excessive hair growth in others [21]. 

Tight hairstyles

Very tight hairstyles such as braids, cornrows, buns and tight ponytails can cause hair loss. Prolonged tension on hair follicles can damage them, causing a type of hair loss called traction alopecia [22]. 

Nutritional deficiencies

Research shows certain mineral and vitamin deficiencies can cause hair loss. Nutrient deficiencies that can cause hair shedding include iron, zinc, selenium, multiple B vitamins and more [23]. Interestingly, excessively high levels of vitamin A may also cause hair loss [23].

Hair loss from chemotherapy

Medications

Hair loss from chemotherapy is well-known, but other medications can cause hair loss as well. These include anticoagulants, antithyroid drugs, lithium, antidepressants, gout medication, and more [24]. 

There are many other factors that can cause hair loss. These include radiation therapy, infections like scalp folliculitis, seborrheic dermatitis, and others. Learn more about different types of hair loss in the article below.

Causes of dehydrated hair

Your hair can become dehydrated — meaning that it doesn’t receive or retain enough moisture — and systemic dehydration can be a factor in some cases [25]. When it lacks moisture, your hair may be dry, frizzy and dull. 

Very dry hair may be more prone to breakage, leading to split ends and even hair loss. Here are some of the most common causes of dry hair. 

Hair care practices 

Excessive heat can dry out your strands [26], including heat from straighteners, curling irons, or holding a hairdryer too close to your hair. Dyeing or chemically treating your hair can also cause dryness, as can harsher types of shampoo [27]. 

Chlorine can cause dry hair

Environmental factors 

Environmental factors can also affect how dry your hair is. In general, sunlight is not good for your hair — excessive sun exposure can cause dry hair [28], which breaks off easily and feels rough or coarse. Other environmental factors, such as chlorine found in swimming pools, can also dry out your hair [29].

Medical conditions

Some medical conditions can affect your hair’s ability to retain moisture. Eating disorders like anorexia nervosa can cause malnutrition, leading to dry, brittle hair [30] and hair loss, among other symptoms. Other medical conditions, such as thyroid disorders, can also cause dry hair, brittleness, and thyroid hair loss [31].

Time marker water bottles can help you stay hydrated

Tips to stay hydrated 

Drinking enough water is important for so many aspects of your health, including your hair. Most people should drink 6-8 cups or glasses of water every day [32] — if you struggle with this, here are some tips to stay hydrated. 

  • Set reminders — If you tend to forget to drink, there are several ways to remind yourself. Setting timers can help, as can health apps on your phone or smart watch that let you know when it’s time to grab some water. Time marker water bottles can also be a good strategy if you don’t like lots of notifications. 
  • Eat hydrating food — Not a fan of drinking water? Have snacks like cucumbers, oranges and watermelon or make them part of your meals. These contain plenty of water and can help you stay hydrated. 
  • Flavour your water — Flavour boosters like lime wedges, lemon, or mint leaves can improve the taste of plain water. Give it a try and see if you reach for your water bottle more often. 
  • Avoid too much alcohol or caffeine — Alcohol and caffeine are diuretics, meaning they increase the amount of urine you pass. If not balanced with extra water, this can make you dehydrated. Indirectly, alcohol may also cause hair loss.
  • Stay topped up on electrolytes — Electrolytes are minerals that help prevent dehydration by regulating fluid balance in your body. They may become low after excessive sweating, vomiting, or diarrhoea, but sports drinks or electrolyte sachets can help with this. 

Getting professional help with hair loss

Struggling with hair loss? Our expert trichologists can help. Dehydration is not the most likely cause, and these hair doctors can identify the reason your hair is falling out.

Using diagnostic trichology tests like hair loss blood tests or a hair pull test, they can diagnose your symptoms and create a personalised treatment plan. Depending on the cause of your hair shedding, you may be a candidate for a natural-looking hair transplant.

A hair transplant is permanent and can give you thick, healthy hair for years to come. Book a free consultation to get started.

Can Dehydration Cause Hair Loss? Understanding Dehydrated Hair, Wimpole Clinic

FAQs

Minimising heat styling, using a conditioner or shampoo for dry hair, and protecting your hair from sun and harsh chemicals can help prevent dryness. If your hair is dry because of an underlying medical condition, it will likely not improve until the condition resolves or is addressed. 

Dehydration may cause a dry scalp or disrupt the flow of nutrients to your hair follicles. If you have hair loss linked to dehydration, your scalp may appear dry and flaky. Dehydrated hair will appear dry, dull, and more prone to breakage.  

Drinking more water may help with hair loss if it’s linked to dehydration in the first place. Also, if you have conditions like seborrheic dermatitis that cause hair loss, you’re more likely to experience flares when dehydrated — so staying well-hydrated can help to prevent this.  

Fixing dehydrated hair may take anything from a few weeks to a few months, depending on the extent of dehydration and the changes you make. Drinking plenty of water, using hydrating hair products, and avoiding heat styling and chemical treatments can help to speed up the process. 

Sources:
  1. How Much Water Do You Need? 
  2. Dehydration in older people: A systematic review of the effects of dehydration on health outcomes, healthcare costs and cognitive performance 
  3. Measured degree of dehydration in children and adolescents with type 1 diabetic ketoacidosis
  4. Clinical symptoms, signs and tests for identification of impending and current water‐loss dehydration in older people 
  5. Water deprivation induces neurovascular and cognitive dysfunction through vasopressin-induced oxidative stress 
  6. Oxidative Stress in Ageing of Hair 
  7. Oxidative Stress–Associated Senescence in Dermal Papilla Cells of Men with Androgenetic Alopecia
  8. The role of oxidative stress in early‐onset androgenetic alopecia 
  9. Oxidative stress in androgenetic alopecia 
  10. Hydration Status and Cardiovascular Function 
  11. Water absorption/desorption of human hair and nails 
  12. The effect of water on the glass transition of human hair 
  13. Water content of hair and nails  
  14. The Water in You: Water and the Human Body 
  15. Dietary water affects human skin hydration and biomechanics 
  16. Seborrheic dermatitis: Self-care 
  17. An update on the microbiology, immunology and genetics of seborrheic dermatitis
  18. Association of androgenetic alopecia and severity of coronavirus disease 2019 
  19. Burden of Hair Loss: Stress and the Underestimated Psychosocial Impact of Telogen Effluvium and Androgenetic Alopecia  
  20. Hair Loss in Women 
  21. The Prevalence of Polycystic Ovary Syndrome: A Brief Systematic Review 
  22. Traction alopecia: the root of the problem 
  23. Diet and hair loss: effects of nutrient deficiency and supplement use 
  24. Overview of Drug-Inducing Hair-Loss 
  25. Status of research on the development and regeneration of hair follicles 
  26. Hair Shaft Damage from Heat and Drying Time of Hair Dryer 
  27. Shampoo and Conditioners: What a Dermatologist Should Know? 
  28. The biology of hair care    
  29. Does Pool Water Affect your Skin and Hair? 
  30. Medical assessment of adolescent girls with eating disorders: An evaluation of symptoms and signs of starvation 
  31. Skin findings in thyroid diseases 
  32. Water, drinks and hydration – NHS 
Dr. Umear Ahmad (GMC)
Medically reviewed by Dr. Umear Ahmad (GMC)Updated on September 22, 2024
The Wimpole Clinic offers FUE Hair, Beard & Eyebrow Transplants & Trichology.
Talk to a specialist ☎ 020 7935 1861.

Book a consultation

Simply fill in your details in the form below and we'll get in touch with you shortly.