Do Hair Darkening Shampoo Bars Work? (The Truth)

If you’re looking for a gentler and more natural alternative to traditional hair dyes, you may have come across the concept of shampoo bars. But do hair-darkening shampoo bars work? How effective are they when compared to regular hair dye?

Do Hair Darkening Shampoo Bars Work

Hair-darkening shampoo bars can be an effective and gentle way to darken your hair, without resorting to the use of harsh chemicals. They are useful for blending in gray hairs and add depth and vibrancy to the existing color. They are also safe for regular use.

However, it’s important to invest in a good quality brand and bear in mind that the results may be subtler and less long-lasting than traditional hair dye.

What Are Hair Darkening Shampoo Bars?

As the name suggests, hair-darkening shampoo bars are a shampoo in bar form that is designed to darken the hair.

These shampoo bars are a gentler and more natural alternative to darken the hair than traditional hair dyes.

They often contain ingredients such as henna, indigo leaves, black tea, activated charcoal, and blackberry leaf extract. These ingredients are known to dye hair a darker color.

These bars can also be used to add depth and vibrancy to your hair color.

Do Hair-Darkening Shampoo Bars Work?

Yes, provided you buy a good quality brand. It’s also important to buy from a reputable seller and check out customer reviews before buying a hair-darkening product online.

Low-quality hair-darkening shampoo bars may not work as well, or may even be damaging to your hair.

One potential problem with hair-darkening shampoo bars is, even if they work, the results won’t last, and will gradually fade each time you wash your hair.

That being said, they usually contain natural ingredients and are gentler than regular hair dyes, so it is fine to use them each time you wash your hair to keep your color looking fresh.

How Do Hair Darkening Shampoo Bars Work?

Unlike a regular permanent hair dye, which penetrates the cuticle of the hair and replaces your natural hair pigment with the dye’s pigment, hair-darkening shampoo bars only coat the strands of your hair.

The pigments from these shampoo bars sit on top of the hair rather than being absorbed into the hair fiber.

It coats the hair with plant pigments that darken the hair. This is why the color will gradually fade and wash out each time you shower.

However, their natural ingredients make them safe for regular use, as they should not be damaging to the hair.

Who Can Use A Hair-Darkening Shampoo Bar?

A hair-darkening shampoo bar may be a good option for those who:

  • Want to color their hair without using harsh chemicals like ammonia
  • Want to subtly blend in gray hairs
  • Want to enhance the hue of dyed hair without re-dying it
  • Want to try going a darker shade without the commitment

A lot of these shampoo bars may also contain red or copper pigments, so they can be helpful for those who are looking to maintain their red color.

However, they should be avoided by those who wish to enhance blonde shades. Blue or violet shampoos are best suited to this purpose.

How To Use A Hair-Darkening Shampoo Bar

a hand holding a shampoo bar above a table

Always do a patch test 48 hours in advance before using any new product for the first time.

It’s also a good idea to check the ingredients list of the shampoo bar before using it, to make sure you’re not allergic to any of the components.

Step 1: Wet Your Hair

First, saturate your hair with warm (not hot) water. This will ensure you get a bubbly foam when you shampoo your hair.

Step 2: Lather Up

Next, you need to wet the shampoo bar under the water. Then rub between your palms to make a foam to lather onto the hair. Alternatively, you can massage the bar directly on your hair if you prefer.

Step 3: Work Into The Hair

Lather your hair as you would with a conventional shampoo. However, instead of just focusing on the scalp and roots of the hair, make sure you work the foam to the ends of your hair.

You need to ensure the pigments cover the entire surface of the hair for the best result.

Step 4: Leave In For 10-15 Minutes

Leave for 10-15 minutes to ensure the color develops properly. You can also leave it on a little longer if you like (always check product packaging for individual products recommended developing time).

Step 5: Rinse and Condition

Once you’re done, rinse the shampoo thoroughly from your hair. Also, make sure the shampoo is rinsed from your skin.

Make sure no residues are left as the dye can transfer and stain surfaces. Then use your regular conditioner as required, to restore moisture to the hair.

Step 6: Comb And Style As Usual

Next, dry, comb, and style your hair as usual to see the results!

If the color is not as dark as you’d like, you may have to repeat this process a few times to see more significant results.

Alternatively, you could try leaving the shampoo on your hair for longer the next time.

How Long Does It Take For Hair To Get Used To Shampoo Bar?

Some people may experience a transition period when they start using natural products to wash their hair.

If you’ve been using a shampoo with synthetic ingredients for years, then this is more likely.

Your hair may feel greasy or waxy for a few washes, as your scalp readjusts by overproducing sebum. This should balance out after a few washes.

You can ease this process by using an apple cider rinse to balance out your hair.

What Are The Cons Of Shampoo Bars?

two shampoo bars on top of parchment paper.

Although shampoo bars have many benefits, such as being natural, long-lasting, and good for the environment, there are a few disadvantages, such as:

  • The transition period, where your hair may feel greasy or waxy than normal
  • They need proper storage
  • They expire faster due to natural ingredients
  • Can interact with hard water, creating waxy buildup on hair
  • Don’t always cater to specific hair types
  • May leave a residue on the hair

What Foods Darken Your Hair?

Foods rich in antioxidants, copper, and vitamins A, C, E, B6, and B12 can all help to boost melanin production in your hair.

Therefore, it’s important to follow a varied, healthy diet to keep your natural hair color looking its best.

Try eating the following foods to boost melanin production in your hair:

  • dark chocolate
  • leafy greens
  • beans
  • lentils
  • fish
  • meat
  • eggs
  • dairy
  • berries
  • nuts and seeds
  • whole grains

It’s important to bear in mind, however, that while these foods can boost the intensity of your natural color, they won’t make blonde hair brunette.

Can White Hair Turn Black Again?

Unfortunately, if the cause of your graying hair is genetic, it won’t be able to restore its former color naturally.

Once your hair follicles lose their melanin, they are unable to produce it again. Your hair naturally produces less melanin as you age. This results in hair turning gray, and then white once melanin production has stopped completely.

Disclaimer: This site is not intended to provide professional or medical advice. All of the content on is for informational purposes only. All advice should be followed at your own discretion. Ingredients may change at any time so always check the product label before using. Check our full disclaimer policy here.

Photo of author

Nicola Sloan

Nicola is a freelance writer and researcher whose specialisms lie in health and wellness, beauty, and psychology. She has fine, wavy hair and is a big fan of co-washing every alternate day between shampoos (as dry shampoo makes her sneeze!)