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How Long You Should Leave Dye in Your Hair?

How Long You Should Leave Dye in Your Hair?

If you’ve got some hair goals, coloring your hair at home might sound practical and economical since the cost is much lower than going to a salon.

However, there are many factors to consider when it comes to dyeing hair, so read our guide first to avoid a potential hair crisis.

How Long You Should Leave Dye in Your Hair? Most hair dyes should be left for a minimum of 30 minutes and a maximum of 45 minutes.

Permanent dyes contain harsh chemicals, and leaving it on your hair too long can cause damage, resulting in dry and brittle strands.

Does Hair Dye Get Darker the Longer You Leave It In?

Not all hair dyes were created equal, and the result will depend on whether you’re using semi-permanent or permanent color. While permanent dyes change hair color with the oxidation process, semi-permanent dyes only coat the surface of your hair shaft.

When you use semi-permanent hair dye, they will get darker the longer you leave them in your hair because it doesn’t contain a developer or lightening agent.

You can look for vegan and cruelty-free options that won’t damage your strands even if you leave the dye longer than 30 minutes. On the contrary, a permanent dye relies on the oxidation process, which will lighten or darken your hair.

Unfortunately, it contains harsh chemicals like ammonia and peroxide, so you should not leave it on your hair for an hour. Since it contains developer, opt for a lighter shade of the color you’re trying to achieve.

The key is to let the dye set, as rinsing too soon will lead to an uneven color result. On the other hand, leaving it for too long can damage your hair, resulting in dry and brittle strands.

How Long Should You Leave Hair Dye on Roots?

If you just need to cover up your gray roots, opt for semi-permanent dyes that are less damaging. Most of the time, the dye should be left for 30 to 45 minutes, and not an hour.

If you’ve got some resistant grays, it’s better to do some strand tests to determine the right amount of time you’ll need to get the color that you want. 

Check: Can You Dye Wet Hair

What Happens If You Leave Hair Dye Longer?

Hair dyes whether it’s permanent or semi-permanent should be left around 30 to 45 minutes. Leaving the dye longer can cause irreversible damage to your hair—dry, brittle strands and hair fall.

For permanent dyes that involve chemical process, 30 minutes is enough for the chemicals to develop and fully permeate the hair.

Leaving it for too long can make your hair too dry and weak, and eventually breaks off.

On the other hand, semi-permanent dyes only coat the surface of your hair with color, so it’s less damaging even when left for more than 30 minutes.

Since it doesn’t contain a lightening agent, it can make your hair darker the longer you leave them, but it will never lighten your hair.

Hair Coloring Mistakes You Should Avoid

  • Choosing hair colors based on the picture on the box

Don’t expect that you’ll get the exact shade when you apply the dye, as everybody’s hair is different. Do you know that your hair’s porosity and texture matter when it comes to color? 

Most of the time, the swatches give you the color estimates on how it would look, especially on silver hair. However, if you’ve got dark hair, you cannot go blonde instantly.

For permanent dyes, go for a darker shade as the developer tends to give off a lighter color. On the contrary, semi-permanent dyes can give you darker results, but won’t be able to lighten your hair.

  • Not knowing the harmful ingredients in your dye

You might think it’s just easy to try at-home hair coloring as you can have it fixed at a salon when gone wrong. Unfortunately, some box dyes contain harmful ingredients and don’t react well with salon dyes.

For instance, the metallic dye can cause an unexpected chemical reaction when you put bleach or lightener on it. To avoid further damage, tell your hair colorist about the product you’ve used in your hair.

  • Not taking your hair texture into consideration

Do you know your hair thickness and texture play a role in how chemical reaction on dyes takes place? Different hair types have different cuticle layers, which affects how the dye penetrates your hair.

While a kinky or Afro hair has 8 to 12 cuticle layers, the Asian hair has 16 to 18 layers and European hair for around 10 to 16. The fewer the layer, the quicker the bleach and dye will penetrate the strands.

This means that coarse and frizzy hair will absorb color faster than fine textures. So, if you’ve got curly hair, pick for a warmer shade as it will likely become cooler-toned when you dye it.

  • Uneven application of the product

It’s really challenging to apply dye on small areas if you’ve got an already-colored hair. However, the hair at the roots will react differently to the rest of your strands since you’re basically putting a color on top of a colored hair.

  • Not following the desired processing time

When it comes to at-home hair coloring, you should get the timing right for the dye to work well. If you leave it on your hair for too long, it might result in a darker hair, as well as irrevocable damage.

On the other hand, taking it off too soon won’t let the color process perfectly. Ideally, you should leave the dye for 30 to 45 minutes, so you’ll avoid further issues with your hair.

  • Drastically bleaching your hair

If you want to go blonde from dark, better seek a professional’s help rather than doing the hair color on your own. Do you know that bleaching is one of the most dangerous and intense chemical processes?

Some women face issues on getting unflattering orange hair, while others suffer the consequences of harsh bleach, resulting in falling and over-processed hair.

  • Altering the previously colored hair

If you’ve got previously bleached hair or lightened highlights, altering it with hair dye won’t do any good. A porous hair won’t respond well to chemicals, resulting in over-colored or under-colored hair.

More than that, it can turn into murky tones—think of unflattering greens and blues. The best thing is to let your hair breathe for a few months, or go to a professional colorist to fix your hair.

How to Prep Your Hair for Color?

Make sure your hair is in good condition

Hair dyes tend to dry out and damage your strands, so make sure your hair is strong and hydrated. If you can, go for a deep conditioning treatment, or apply hair serums like avocado oil, coconut oil, and sunflower oil to nourish your hair. 

You can check your hair’s elasticity and porosity my stretching it a bit, and letting it go back to its form. If you’re in doubt with your hair’s condition, don’t do the coloring yet as it will add further damage to your strands. 

Avoid over-washing your hair

When we say deep condition your hair, it doesn’t mean washing it over and over again. Do you know tap water can dry out your hair even more, stripping its natural oil and moisture? Instead of a clarifying shampoo, use gentler hair products without sulfate and harmful ingredients.

Experts recommend not washing your hair before coloring it, so the natural oils can protect your hair. Also, you may think of having a coconut oil hair mask overnight to allow deeper penetration of oils. This way, you’ll keep your strands healthy throughout the coloring process.

How to Take Care of Dyed Hair?

Use products specifically for color-treated hair

It’s time to toss your favorite clarifying shampoo and opt for ones that will help you keep the hair color longer. Did you know that hair products designed for your specific hair color will keep it looking full and vibrant? 

In fact, there are salon-grade shampoos that include quinoa, elastin protein, coconut milk, rice bran oil, and other antioxidant-boosted formulas that will make sure your fresh dye job has a long life.

On the other hand, some ingredients only strip your hair color and make your strands brittle. Also, you should wash with cool water, as hot water will only open the cuticle of your hair, making the color fade faster.

Deep condition your hair

Conditioners and hair serums are great, but you might think of having hair masks and treatments every week. Do you know that the healthier your strands the longer the color will look vibrant?

Technically, water-based conditioners coat your strands and smooth the cuticle to repair damage, while keeping your hair hydrated and nourished.

If you want to go natural, think of coconut oil or olive oil as your hair mask or even a pre-wash treatment. Keep in mind that oil repels water, so you should apply it to dry hair.

Check: Best Deep Conditioners For Bleached Hair

Limit the use of heat styling tools and sun exposure

If you can, go for hairstyles that don’t require curling or flat iron. Also, use hair products with UV protection when going outdoors, as well as heat protection spray.

If you find ponytails too boring, curl your hair with a hair tie by bringing your strands into a bun, letting the curls sit for a while, then rocking them loose.

Also, think of creative braids like fishtail, French, Dutch, and waterfall that will showcase your skills without damaging your hair.


How long should you leave the dye for covering gray roots?

If you’re using semi-permanent dye, 30 to 45 minutes of time should give good coverage to your grays. When it comes to permanent dyes, the same processing time applies, but don’t leave it for an hour, as it will likely damage your hair.

Which gives better color result, permanent or semi-permanent dye?

If you just need to darken your hair, a semi-permanent dye might be perfect for you. It’s great for adding shine and enhancement to your hair color, but it can never lighten it up. If you need some highlights or lighter hair color, opt for permanent dyes.