Top Causes of Dull Hair & How to Fix

by GENA MARIE

Are your curls looking dull? If your tresses are looking less vibrant than normal you may be wondering where the shine has gone. There are several reasons that cause dull hair, but they can easily be resolved to bring your curls back to their glossy, shiny glory.

Glossy locks are the universal sign of healthy hair. There are several possible causes of dullness in hair, including build-up from products or hard water, dryness, damage, and even medical conditions and nutrient deficiencies. We’re going to cover each common cause of dull hair so you can better assess why your hair is lacking shine and some ways to get shinier, healthier tresses.

Table of Contents

Product Build-Up

Build-up is the most common cause of dull hair. Visual signs of build-up on the hair shaft include a dull appearance, stringiness, lack of shape or “bounce” in your curls, and frizz that is static-y. The feeling of build-up can be unpleasant and leave a residue on your hands when touching your hair. Hair with build-up often feels sticky, tangly, or repels water and products, preventing the hair from absorbing the key moisture it needs to be healthy. Product excess can also accumulate on the scalp leading to more serious issues such as hair loss and dandruff. 

All hair products have the potential to cause build-up due to their ingredients. Most of them contain ingredients that are hydrophobic, meaning they repel water. Common forms of hydrophobic ingredients include film-forming polymers and emollients. Curly hair products often also contain conditioning ingredients that are cationic, meaning they are designed to bind to the hair. These are good because they seal in moisture and coat the hair to reduce frizz, but the excessive layering of products that contain them without proper cleansing can lead to unwanted build-up.

Many of these common ingredients are water-soluble, meaning they can be easily removed with your mild, “curly girl-friendly” shampoos. Others are not water soluble, so they may need a harsher sulfate-based cleanser to be washed out, or they may cause dull hair with repeated use, especially when layering additional products when refreshing in between washes. 

Dry Hair

Curly hair can easily become dry due to a lack of sebum, our scalp’s natural oil, leading to a dull appearance. This becomes even more prominent as we age, because the scalp produces less sebum. 

There are some ingredients that can make your hair dry, so they should be avoided if you are trying to reduce dullness. These are often derived from alcohol, and are generally used for their fast-drying properties:

  • Denatured Alcohol or Alcohol Denat.
  • Isopropyl Alcohol
  • Ethanol
  • Isopropanol
  • Propyl Alcohol
  • Propanol

Dullness from dry hair can also occur from a lack of conditioning. Using a conditioner after every wash is critical, especially for naturally curly hair that is easily dried out. A conditioner contains cationic, moisturizing ingredients that bind to the hair creating a soft, shiny feel. Conditioners are also acidic, so they lower the pH of our hair after shampooing, restoring shine and vibrancy.

Rinse-out conditioners are great for your usual routine, but incorporating deep conditioners every once in a while is also necessary, particularly for dry or damaged hair. If you have this hair type, try deep conditioning once per week, and alternate deep conditioners that contain protein, like the Curlsmith Multi-tasking Conditioner, with protein-free deep conditioners, like the Hydro Creme Soothing Mask or the Double Cream Deep Quencher. For healthy hair that does not get super dry, deep conditioning monthly should be sufficient to maintain moisture levels.

Damage = Dullness

Dullness can be the result of damaged hair, because of its raised or chipped cuticle. Cuticle damage frequently occurs from using heat styling tools, chemical straightening treatments, bleaching, and hair dye, but it can also happen with regular styling and brushing. If you have naturally curly hair it’s recommended to use these techniques as little as possible. If you can’t let them go, you can use a bond-builder like Curlsmith’s Bond Curl Rehab Salve to restore the broken bonds caused by the damage and repair the hair. Bond Curl and protein deep conditioners strengthen the hair and help restore shine.

Improper Cleansing can lead to dullness

How often you wash your hair can have a direct impact on dullness. For most hair types it is not recommended to wash your hair daily. When we wet our hair, the inner layers of the hair swell, causing the cuticle to raise and moisture and protein to release. Repeated swelling puts stress on the cuticle, and can lead to damage over time, especially if the hair is left wet too long. Damaged hair has a raised cuticle structure, which doesn’t reflect light and makes it look dull. 

The type of shampoo you use can also have an impact on its shine. Using a strong clarifying or sulfate shampoo too often may dry your hair out and make it look more dull. Using a co-wash or a sulfate-free shampoo is a great way to gently cleanse your hair in between stronger clarifying sessions. These are ideal for people who may get very oily and can’t go long in between washes, swimmers, or professions that require frequent washing.

However, only using a co-wash or a very mild shampoo can also result in dull hair, because these types of cleansers cannot effectively remove build-up. They are ideal to use in rotation with a more cleansing option, as mentioned above, but they cannot be your only detergent. 

A good wash day is critical to ensure you’re thoroughly removing product residue from your scalp and hair. Incorporating mechanical cleansing, which refers to using your hands to physically scrub away build-up while shampooing, is also key to getting a thorough cleanse with mild shampoos. Scrubbing should be focused on the scalp only, adding enough water to create a foam that will coat the rest of the hair and cleanse away build-up as you rinse.

Hard Water

Water residue is another common cause of dull hair. It is estimated that 85% of households in the US have some degree of hard water. Hard water is water that has a high mineral content, typically calcium and magnesium. You can have your water tested to determine if it contains these minerals. You can also look for signs in your home: a white, powdery residue on any surfaces where water sits or collects, water spots on dishes and shower walls, rough or dingy-looking laundry, and less lathering with soaps and detergents.

Hard water has a negative impact on our skin, scalp and hair, including dryness and dullness. This is due to the cationic, positive charge that these minerals have, which causes them to bond to your hair. If you notice that your shampoos don’t foam very easily when you know they should, or if you notice a sticky, stripped feeling on your hair after cleansing, this could be a sign that you have hard water build-up. 

Low-poos, co-washes and even regular sulfate shampoos are not strong enough to remove serious mineral build-up from hard water. Using a chelating shampoo is the only way to remove it. Look for shampoos that contain:

  • Disodium EDTA
  • Tetrasodium EDTA
  • Trisodium EDTA
  • Pentasodium Pentetate
  • Sodium Gluconate

Installing a water softening system in your home, using a water softening shower head, or washing your hair with purified water are the best ways to prevent hard water build-up from happening. Otherwise, routine use of a chelating shampoo will be necessary to remove hard water build-up from your hair and prevent dullness.

Chlorine or Sea Water

Water with chlorine or salt can also be damaging to the hair and cause dullness. If you’re someone who swims frequently, it's critical to remove the chlorine from your hair afterward by shampooing or clarifying. Swimmers should wear a cap or cover to protect their hair from chlorine. You can also use a pre-poo hair oil or apply a conditioner or deep conditioner to your hair prior to going in the water to help your hair absorb less of the chlorine or saltwater.

Environmental Factors that Can Cause Dull Hair

Various environmental factors, particularly in the air, can cause a dull appearance on the hair. Prolonged UV exposure from the sun, extremely dry air, and harsh wind can cause hair to become dry. Pollutants in urban areas can also accumulate on the hair, leading to a dull appearance.

Regularly incorporating clarifying will prevent build-up from these external agents, but you can also prevent them from accumulating. To protect your hair from the sun or dry air, wear protective coverings such as silk scarves or a hat. Using a sealing oil such as Curlsmith’s Bonding Oil to finish your style can also help lock in moisture to prevent your hair from becoming dry from the weather. 

Health Conditions 

How healthy we are internally is often reflected in our hair, skin, and nails. Dull hair can be a result of nutrient deficiencies, poor diet, and medical disorders. Eating a balanced diet, rich in healthy fats, whole grains, protein, iron, zinc, and Vitamins A-E will ensure your hair remains shiny and strong. Hair supplements can help replenish these nutrients and reduce the appearance of dull hair.

Some causes of dull hair or lack of shine may be from an underlying hair shaft disorder. These can be due to an underlying genetic condition but are often caused by damaging hair practices. These practices can lead to the fragility of the hair or changes in the hair’s shaft texture and shine, causing hair to appear dull, sparse, and brittle. Close examination of the hair may show white nodules with frayed ends of hair. Avoiding trauma to the hair, either physical, thermal, or chemical, is important in reducing further damage to the hair shaft.

Say Goodbye to Dull Hair

Many factors can lead to dull hair, but fortunately they are all easily resolved. Clarifying regularly, cleansing properly, conditioning the hair and eating a healthy diet will go to great lengths to keep your hair shiny and healthy. If you want to boost those results, you can use shine-enhancing products like Curlsmith’s Shine Recipe, which contains nourishing ingredients that will enhance the appearance of your curls and make them look as vibrant as ever.