If you’ve ever colored your hair or thought about trying a new shade, you’ve probably heard about developer. But what does developer do to hair, really? Many people confuse it with bleach or think it’s just another chemical, but its role is actually more nuanced. In this guide, we’ll explore how developer works, what it does to your hair, and why it’s essential for hair coloring and treatments.
What Is Hair Developer?
Hair developer, also known as peroxide developer, is a chemical solution that works with hair dye or bleach to change your hair’s color. It comes in different strengths, measured in volumes:
-
10 volume (3%) – Gentle, adds shine, deposits color without lightening much.
-
20 volume (6%) – Standard for permanent color, can lift hair 1–2 levels.
-
30 volume (9%) – Stronger lift, used for lightening dark hair.
-
40 volume (12%) – Maximum lift, typically for high-lift blondes.
Developers are designed to open the hair cuticle, allowing color molecules to penetrate and interact with your natural hair pigment.
How Developer Works with Hair Dye
When you mix hair dye with a developer, a chemical reaction occurs. Here’s what happens step by step:
-
Cuticle Penetration: Developer opens the hair shaft so dye can enter.
-
Pigment Change: The natural pigment (melanin) in your hair is lightened, and the new color molecules bond with it.
-
Color Fixing: Once processed, developer helps the hair shaft close, locking in the new color.
This is why people often ask, “what does developer do to hair dye?” — it’s the key to achieving permanent, vibrant hair color.
Developer’s Role in Hair Color
When paired with hair color, the developer determines how much the hair can lighten or how well the color adheres.
-
Permanent Hair Color: Requires a developer to lift natural pigment and deposit new color.
-
Demi-Permanent Color: Uses lower-volume developers to subtly enhance your natural shade.
-
Highlighting: Higher-volume developers are often needed for lifting hair several shades lighter.
In short, without developer, most hair dyes wouldn’t penetrate or stay on your hair effectively.
What Does Developer Do to Hair Without Bleach?
Many think developer only works with bleach, but that’s not true. Even without bleach:
-
It slightly lifts your natural pigment, allowing hair color to take effect.
-
It helps even out color, especially for permanent or demi-permanent dyes.
-
It can make hair more porous temporarily, which is why post-color conditioning is important.
So even if you’re not bleaching, developer is still active in opening the hair cuticle and helping dye molecules penetrate.
What Does Developer Do to Hair By Itself?
Developer alone (without dye or bleach) is mostly mild and temporary on hair. Its effects include:
-
Lightening hair slightly over time (with higher volumes).
-
Raising the hair cuticle, which makes hair temporarily more porous.
-
Activating chemical reactions in treatments like protein or toner solutions.
However, using developer alone won’t give dramatic color changes — it’s the combination with dye or bleach that transforms your hair.
Tips for Using Developer Safely
-
Choose the right volume based on your desired result.
-
Perform a strand test before full application.
-
Avoid over-processing, which can cause dryness or breakage.
-
Use conditioning treatments after coloring to restore hair health.
FAQ: What Does Developer Do to Hairs?
Q: Can I use developer on its own?
A: Yes, but it mostly opens the hair cuticle and can slightly lighten hair. It won’t add permanent color.
Q: What volume developer should I use with hairs dye?
A: 10–20 volume is standard for most permanent colors; higher volumes are for lifting dark hair.
Q: Does developer damage hairs?
A: When used correctly, it’s safe. Overuse or high volumes on damaged hair can cause dryness or breakage.
Q: Can I use developer without bleach for highlights?
A: Lower-volume developers can subtly lift hair, but dramatic highlights usually require bleach.
Q: How long should developer stay on hairs?
A: Follow the hair dye instructions; over-processing can damage your hair.
Conclusion
Understanding what developer does to hair is key for anyone exploring hair coloring. It’s not just a chemical — it’s the engine that lifts your natural pigment, allows color to bond, and creates lasting results. Whether you’re using it with hair dye, bleach, or by itself, knowing how it works ensures you achieve your desired shade safely and beautifully.
