What Is Hygral Fatigue and How Does It Affect Hair?

What Is Hygral Fatigue and How Does It Affect Hair?

What is hygral fatigue?

Hygral fatigue is damage to your hair follicles caused by swelling from excessive moisture. To understand how hygral fatigue occurs, it’s helpful to understand the three layers of hair:

  • Cuticle. Your cuticle is the outer layer of your hair that’s made up of dead cells that overlap like the scales of a fish. It helps lock moisture into your hair and protects the inner cortex and medulla.
  • Cortex. Your cortex is the thickest layer of your hair and gives your follicles their strength, texture, and color.
  • Medulla. Your medulla is the soft innermost layer of your follicle. It isn’t present in all hairs.

For water to enter a hair follicle and cause hygral fatigue, it needs to make it past the protective cuticle and into the cortex. People with highly porous hair, or hair that has cuticle cells spaced widely apart, are most susceptible to hygral fatigue.

Symptoms of hygral fatigue-

On a microscopic level, hair that’s experiencing hygral fatigue undergoes several physical changes, such as:

  • weathering (degeneration of hair shaft)
  • damage and raising of cuticle cells
  • loss of the protective fatty layer coating your hair
  • exposure of your hair follicle’s cortex

Damage from hygral fatigue can lead to a variety of symptoms, such as:

Hygral fatigue may even cause dryness because damage to the cuticle impairs the follicle’s ability to hold moisture.

Causes of hygral fatigue

Repeated swelling and unswelling of your hair follicles from excessive moisture retention can lead to hygral fatigue. Irreversible damage occurs when your hair stretches by more than about 30 percent of its original size.

The following are some factors that may contribute to the development of hygral fatigue.


Like with many aspects of your hair, your genetics play a role in determining how porous your hair is. People with low hair porosity naturally have tightly packed cuticle cells that make it difficult for water to enter the follicle. People with high porosity have cuticle cells that are more distantly spaced.

Over-moisturizing hair

Over-using shampoos and conditioners designed to moisturize your hair may put you at risk of developing hygral fatigue, especially if you have naturally porous hair. Frequent use of deep conditioners or hair masks may also make you vulnerable to developing hygral fatigue.

Damaged hair

Damaged hair is generally more porous than undamaged hair because the protective cuticle cells may lift or break. Excessive chemical treatment, treatments that use high-heat, harsh grooming, and environmental factors can all contribute to hair damage.

Loss of protective oils

Your hair is naturally hydrophobic, meaning that it repels water. An oily substance called 18-metil eicosanoic acid (18-MEA) coats your hair follicles and gives them hydrophobic properties. Stripping your hair of this natural oil by over-shampooing or using other overly alkaline chemicals can reduce your hair’s water-repelling properties.

Loss of pH balance

The pH balance of your hair is a measure of how alkaline or acidic it is on a scale from 1 to 14. Values below 7.0 are considered acidic, and values greater than 7.0 are alkaline.

The pH of a healthy hair shaft is between about 3.67 and 5.5 for a healthy scalp.

Using overly alkaline products may damage your hair by removing the protective 18-MEA layer. Alkaline shampoos may increase friction between hair fibers, which leads to a breakdown of your cuticle.  The lower pH of shampoos causes less frizziness.

Is hygral fatigue the same as over-moisturized hair?

The terms “hygral fatigue” and “over-moisturizing” are synonyms that are usually used interchangeably. Sometimes the term “over-moisturized” specifically refers to the act of using too many hair products that moisturize your hair like conditioners or oils.

How to treat hygral fatigue in your hair

Hair that’s damaged by hygral fatigue or other causes is susceptible to further damage. You won’t be able to undo the damage you’ve already done. Your best option is to minimize future damage while waiting for healthy hair to grow out.

Change your hair products and washing routine

If your hair is over-moisturized, it’s a good idea to minimize your use of shampoos and conditioners designed to moisturize your hair. You may want to reduce your hair-washing frequency to avoid stripping your hair of its natural protective oils.

Reduce other sources of damage

Reducing other sources of damage may help you prevent further damage that contributes to the breakdown of your cuticle layer.

Potential causes of damage include:

Cut out damaged hair

Unlike your skin, your hair can’t heal itself. If your hair is damaged, you’ll have to be patient while healthy hair replaces the damaged sections. In the meantime, if you’re developing split ends, it’s a good idea to cut them out so they don’t spread to healthy sections of your hair.
How to prevent hygral fatigue-
Damaged hair is particularly susceptible to hygral fatigue because the protective cuticle layer becomes more porous. Taking steps to reduce your overall amount of damage may help you reduce your chances of developing hygral fatigue.

Shampoo gently

When you shampoo your hair too vigorously, you can damage the outer layer of your hair. The American Academy of Dermatology Association recommends gently massaging shampoo into your scalp and letting it flow the length of your hair as you rinse.

Wear a swim cap

Swimming pools are filled with chlorine to kill bacteria. This chlorine is harsh on your hair, but wearing a swim cap can minimize the amount of chlorine that comes into contact with your follicles.

Brush your hair properly

If you have curly hair, it’s a good idea to use a wide-tooth comb while your hair is still wet.

Use shampoo with a low pH

AlkalineTrusted Source shampoos tend to strip the protective 18-MEA layer from your hair follicles. At this time, it isn’t clear what the best pH value is for hair health, but using a shampoo with a pH similar to your scalp’s pH value of 5.5 may help you prevent the breakdown of your 18-MEA layer.

Use coconut oil as a pre-wash

Coconut oil  is one type of oil that’s been found to reduce protein loss in your hair when used as a pre-wash. Coconut oil is made up of a medium-chain fatty acid called lauric acid that’s thought to allow it to be absorbed into your hair follicle easier than other oils.

Hygral fatigue is damage to your hair follicles caused by repeated swelling and unswelling. It occurs when excessive moisture penetrates the outer layer of your hair and reaches the inner cortex. Over time, repeated swelling from hygral fatigue can lead to symptoms such as frizziness, brittleness, and dullness.

Your genetics play a role in determining how porous your hair follicles are, but minimizing hair damage can help keep the protective outer layer of your hair healthy.

Last medically reviewed on November 13, 2020

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