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How Long to Leave 10, 20, 30, 40 Volume Developer in Hair?

aida turner

Published by Aida Turner

Fact checked by Annie

Hair developer is a chemical agent used in hair coloring and lightening to open the hair cuticle, allowing the color of the hair dye to penetrate the hair shaft. The developer should be left in the hair for a specific time to achieve the desired results.

The ideal duration for leaving a developer in your hair varies between 10 and 30 minutes, depending on developer volume, the desired coloring results, and other personal factors such as your hair type, texture, condition, or even your room’s temperature.

Professional hairdressers don’t recommend leaving the developer in your hair for more than 30 minutes as it causes oxidative damage to human hair, such as increasing cysteic acid content, cuticle damage, dryness, breakage, and protein loss. This oxidative damage increases with the strength of the hair developer, according to a 2015 study titled “The Effect of Hydrogen Peroxide Concentrations on Hair Strength”.

On the other hand, not leaving the developer long enough on your hair gives you poor color results, such as uneven, inconsistent, patchy color or an insufficient lift.

How Long to Leave a 10-Volume Developer in Hair?

The ideal time to leave a 10-volume developer in hair ranges between 10 to 30 minutes, according to manufacturers like Kenra Professional.

A subtle lift or color deposit without lightening requires around 10 to 15 minutes, while a noticeable lift or color change needs more time, up to 30 minutes. Fine or damaged hair processes color faster due to its porosity, requiring less time, while coarse or healthy hair resists color, necessitating a longer duration. Lighter hair requires less developer time, whereas darker hair requires more to achieve the desired lift or color change.

How Long to Leave a 20-Volume Developer in Hair?

You should leave a 20-volume developer in your hair for 20-30 minutes, depending on the desired results and your hair type. We don’t suggest leaving it in for more than 30 minutes in your hair to prevent significant breakage and damage. A 20-volume usually fully processes in about 10 minutes if you have blonde or fine hair, whereas dark or coarse hair typically needs up to 30 minutes.

You must check the manufacturer’s guidelines on the bleach or developer packaging, especially when using a 20-volume developer for toning or dyeing without bleach, where a 15-30 minute duration is typically recommended. Overextending the advised time, particularly with bleach, can lead to overprocessing and potential hair damage.

How Long to Leave a 30-Volume Developer in Hair?

We recommend to leave 30-volume developer in your hair for 15 to 30 minutes. The ideal duration can vary depending on the hair’s texture and the desired result, as a 30-volume developer can lighten the hair’s original color by two to three levels.

Monitor your hair carefully during hair dyeing to avoid over-processing of the developer. If the desired lightness is not achieved within 30 minutes, rinse the bleach out and repeat the lightening process a few days later.

How Long to Leave 40-Volume Developer in Hair?

We suggest leaving a 40-volume developer for a maximum of 20 minutes in your hair. 40-volume developers contain 12% hydrogen peroxide and can lift your hair color by up to 4 levels, so use it with caution. Leaving a 40-volume developer on your hair can cause significant hair damage and scalp burn.

When using a 40-volume developer, it’s even more important to monitor your hair closely and rinse it immediately if you experience discomfort or adverse reactions.

What happens if you leave the developer for too long in your hair?

Leaving developer in your hair for too long can result in over-processed hair, becoming dry, brittle, and prone to breakage. The hydrogen peroxide within the developer causes oxidative damage, leading to a rough, open cuticle surface and hair protein loss. Moreover, it can also cause scalp itchiness, irritation, or even chemical burns.

If the developer is very strong, like a 40-volume developer, the risks are higher, and it can even result in hair fallout. Hence, following the instructions provided with the hair dye or bleach products is crucial to minimize potential harm and achieve the desired results.

How can you treat over-processed hair caused by the developer?

If you left the developer on your hair for too long, it could lead to over-processing. To treat over-processed hair, follow these tips:

  1. Choose the right shampoo and conditioner: Use products specifically designed for damaged or color-treated hair to help restore moisture and nourish your hair.
  2. Give hair a protein boost: Use protein treatments or hair masks to help strengthen and repair damaged hair.
  3. Cool it with heat and bleaching: Reduce the use of heat styling tools and avoid further chemical treatments to prevent additional damage.
  4. Cut your hair regularly: Trimming your hair often will remove damaged ends and help hair growth.
  5. Use hair masks and oils: Hair masks, deep conditioners and nourishing oils restore moisture and improve hair health.

What happens if you rinse the hair developer out too early?

If you rinse the developer too soon, the color won’t have enough time to penetrate the hair fully, so the results will not be as vibrant or long-lasting as desired.

The hair dyeing process is a multi-stage process that involves the hair cuticle’s opening, the color’s penetration, and finally, the activation of care and protective substances. If you rinse out the developer too early, you interrupt this process, preventing the color from fully developing and bonding with the hair. 

What are some essential tips for using a hair developer?

When using a hair developer, there are several tips you should keep in mind to ensure optimal results and minimize potential damage to your hair:

  1. Check Expiry Date: Before using a hair developer, always check the expiry date on the packaging to ensure it’s still good to use. An expired hair developer may not provide the desired results and could cause unwanted reactions or damage to your hair.
  2. Dilute Developer AccordinglyDiluting the developer properly ensures that it works effectively without being too harsh on your hair or scalp.
  3. Don’t Use Hair Dye Without DeveloperHair dye needs a developer to work effectively. Without a developer, the dye will not be able to penetrate the hair shaft properly, leading to unsatisfactory color results.
  4. Conduct a Strand Test: Before applying the developer and dye mixture to your entire head, test a strand on a small section of hair. This will help you gauge how your hair will react to the formula and the final color.
  5. Protect Yourself: Apply a protective cream around your hairline and ears to prevent skin irritation, and wear old clothes or a protective cape to avoid staining your clothing.
  6. Apply Evenly: Ensure an even application of the developer and dye mixture to achieve uniform color results.
  7. Rinse Thoroughly: After the recommended processing time, rinse your hair thoroughly to remove all the developer and dye from your hair.
  8. Condition Your Hair: After rinsing, apply a good quality conditioner to help restore moisture and smoothness to your hair.

aida turner

Author of this article: Aida Turner

Founder & Hair Care Consultant

Aida is a cosmetologist and hair care consultant with over 7 years of experience in the beauty industry. Aida has worked with various top salons and smaller hair care brands, offering her product development, formulation, and testing expertise.

Her extensive knowledge of hair care ingredients and their effects on hair health enables her to provide thorough, well-researched, and unbiased reviews on a wide range of shampoos and hair care products. In her spare time, Aida enjoys experimenting with new hair care routines, blogging about her experiences, and helping others achieve their hair goals.