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Can I leave salt on my hair overnight?

Many people wonder if leaving salt in your hair overnight can damage it or cause other issues. Salt is commonly used to add texture and volume to hair, but is it safe to keep it in for extended periods? Here is a comprehensive look at the effects of leaving salt in hair overnight.

What Does Salt Do For Hair?

Salt is used in salt sprays, salt scrubs, and other treatments to give hair a beachy, textured look. It works by absorbing excess oil and product from the hair, leaving it looking matte and textured rather than greasy or limp. Some benefits of using salt on hair include:

  • Adds volume and body
  • Creates tousled, beachy waves
  • Absorbs oil and removes product buildup
  • Gives hair a textured, gritty look
  • Helps enhance natural waves

The effects of salt on hair make it a popular ingredient in texturizing sprays, scrubs, and masks. However, leaving concentrated salt on the hair for too long can lead to dryness and damage.

Is It Safe to Leave Salt in Hair Overnight?

Leaving salt in your hair overnight is generally not recommended. Here’s why:

  • It can cause dryness – Salt is very drying for hair and leaving it on too long can lead to parched, brittle strands.
  • May cause damage – The long exposure to salt can damage and break hair over time.
  • Can lead to a dry, itchy scalp – The salt depletes moisture and oils from the scalp, leaving it tight and itchy.
  • Makes hair fragile – Salt weakens and wears down the structural integrity of the hair cuticle.
  • Color treated hair is at risk – Salt can cause color-treated hair to fade and bleed.

While using salt occasionally in styles and treatments is fine, extended direct contact with concentrated salt can compromise hair health. The drying effects of salt overnight can make hair more prone to breakage, dullness, tangling, and frizz.

What Are the Risks of Leaving Salt in Hair Overnight?

Here are some of the biggest risks and downsides to leaving salt in hair for long periods:

Extreme Dryness

One of the main risks is parched, moisture-depleted hair. Salt is hygroscopic, meaning it attracts and absorbs water. When concentrated salt is left on hair, it will pull moisture and oils from the hair strands and scalp. This can leave hair extremely dry, brittle, and frizzy.


In addition to dryness, leaving salt in hair long-term can cause breakage. Salt wears down and weakens the hair cuticle, causing it to become fragile and prone to snapping. The dehydrating effects of salt also make hair more brittle and susceptible to breakage.

Damage to Color-Treated Hair

Those with color-treated hair need to be especially cautious. Salt can cause treated hair to become dry and the color to fade, bleed, or become patchy. Overnight salt exposure is risky for those wanting to maintain vibrant, evenly-colored locks.

Scalp Irritation

Salt’s drying effects can also extend to the scalp. An overnight application can disrupt the scalp’s natural moisture barrier and cause uncomfortable tightness, itching, and irritation. A prolonged imbalance in moisture can disrupt the scalp microbiome as well.

Weakened Hair Structure

In addition to surface damage, prolonged salt exposure degrades the hair’s structural integrity from within the cuticle outwards. This causes hair to become weakened, lifeless, and prone to tangling and matting. The structural changes are not reversible.

How Does Salt Damage Hair Overnight?

There are a few key ways that leaving salt in hair overnight can cause damage:


Due to its hygroscopic nature, salt draws moisture out of the hair via osmosis. The hair cuticle expands as water diffuses out of the strand and into the concentrated salt on the surface. This causes swelling and damage to the cuticle layer.

Loss of Elasticity

Salt removes proteins and lipids that keep hair elastic. Overnight exposure allows salt to leach these components from the hair, leaving it brittle and prone to cracking.

Cuticle Erosion

The cuticle acts as hair’s protective barrier, and salt degrades this over time. Extended exposure thins and erodes the cuticle, allowing the inner structures of the hair to be damaged.

Stripping of Natural Oils

Sebum provides lubrication and moisture retention for hair. Salt is able to completely strip these protective oils, especially with prolonged exposure. This leads to dry, rough hair with compromised barrier function.

Structural Changes

Within the hair cortex, the salt causes structural changes and damage to keratin proteins. This weakens and breaks down the hair, causing frizz, tangling, and brittleness that cannot be reversed.

Can Salt Water Damage Your Hair Overnight?

Salt water or ocean water can also damage hair if left in overnight. Here’s a look at the risks:

  • Salt water has a very high salt concentration, so leaving it in long-term has a pronounced drying effect.
  • The salt absorbs moisture, oils, and proteins, while minerals deposit on and corrode the hair cuticle.
  • Long-term salt water exposure causes swelling, brittle hair prone to breakage, and extreme dryness.
  • The effects of overnight salt water hair damage can be very difficult to reverse.

Those who swim in the ocean or soak their hair in salt water would be wise to rinse it out before bed to avoid prolonged exposure. The drying effects multiply the longer salt water remains on the hair unchecked.

Which Types of Salt Damage Hair the Most Overnight?

While all salt has a drying effect on hair, some salts are harsher than others. Types of salt that tend to damage hair the most overnight include:

Himalayan Pink Salt

This coarse, dense salt has rugged crystals that can abrade and cut into the hair cuticle overnight. It also has a very low moisture content.

Dead Sea Salt

This is another coarse salt that can scrape and damage the cuticle surface. Its ultra-high mineral content also has very drying effects.

Rock Salt

The large, rigid crystals of rock salt make it extremely abrasive on the hair. Leaving it in long-term causes significant cuticle damage.

Table Salt

Though finer than some salts, table salt has a very high sodium chloride content that efficiently desiccates hair overnight.

Epsom Salt

The compact shape and magnesium levels in Epsom salt make it adept at water absorption. It can severely dry out hair overnight.

Sea salt, kosher salt, pickling salt, and bath salts also have a very high drying potential and risk of abrasion damage when left in hair overnight.

Does Salt Water Damage Hair More Than Chlorine?

Both salt water and chlorine can damage hair with prolonged exposure. However, chlorine tends to be more damaging for a few reasons:

  • Chlorine strips color from hair more aggressively than salt.
  • It permeates the hair shaft while salt only coats the outside.
  • Chlorine removes more moisture and lipids from the hair compared to salt.
  • It opens and lifts the cuticles more harshly, allowing damage to inner structures.
  • Chlorine causes more long-lasting chemical and oxidative damage.

While salt dries out and weakens hair over time, chlorine degrades hair from the inside out with chemical damage. This typically makes overnight chlorine exposure more damaging than salt exposure.

Does Salt Water Damage Hair More Than Fresh Water?

Salt water is significantly more damaging to hair than fresh water when exposed long-term. Here’s why:

  • The salt in salt water is very effective at absorbing moisture from hair.
  • Salt water leaves behind salt deposits that continue damaging hair after swimming.
  • The increased density of salt water causes more friction damage from swimmers’ movements.
  • Salt water erodes and degrades the hair cuticle layer more aggressively.
  • Minerals in salt water deposit on and corrode the hair cuticle overnight.

While fresh water is less ideal for hair than no water exposure, salt water has many amplifying effects that make damage much more severe.

Tips to Prevent Salt Hair Damage Overnight

To avoid the risks of leaving salt in hair overnight, here are some helpful tips:

Rinse Thoroughly After Salt Treatments

After using salt sprays or scrubs, shampoo and rinse hair well to remove all traces of salt from the hair and scalp before bed.

Limit Salt’s Contact Time

When using salt, limit its direct contact time with hair to 5-10 minutes max. Quickly wash it out after to avoid overexposure.

Apply a Deep Conditioner

Using an intensive moisturizing hair mask after salt use can help replenish moisture and nourish hair.

Use a Leave-In Conditioner

Spray on a leave-in conditioner as the last step of your styling routine. This offers continued hydration and protection.

Focus on Gentler Salts

Opt for fine grain sea salts or table salt, which are less abrasive and absorptive than coarser dead sea or Himalayan salts.

Sleep on a Silk Pillowcase

Silk creates less friction and absorbs less moisture than a traditional cotton pillowcase.

Use a Moisturizing Nighttime Serum

Look for a hair oil or overnight mask you can apply before bed to replenish moisture as you sleep.

Key Takeaways

  • Leaving salt in hair overnight regularly can cause dryness, brittleness, breakage, and damage over time.
  • Salt strips hair of moisture and natural oils, weakens the cuticle, and degrades inner structures.
  • Those with color-treated hair face risks like fading and patchiness from overnight salt exposure.
  • Chlorine and salt water tend to damage hair more severely than fresh water when left in overnight.
  • Take precautions like thorough rinsing, minimising contact time, and using conditioners when using salts in hair.

While beneficial in small doses, salt should not be left on hair overnight. Take care to remove it fully and follow up with hydrating products to keep hair healthy and minimize salt-related damage over time.