Ingredient review
Disperse Black 9
INCI: Disperse Black 9
A synthetic hair dye that provides black color but may cause irritation or allergic reactions in sensitive individuals.
In plain English
Disperse Black 9 is a man-made dye used to give hair a black or dark shade. It is often found in semi-permanent and temporary hair color products. Like many hair dyes, it can sometimes cause skin irritation or allergic reactions, especially if you have sensitive skin or a history of reactions to hair color.
Review score
Safety, usefulness, and evidence
Useful in the right context, but not low-maintenance
The evidence base is useful, but some claims depend heavily on the formula.
Main practical flags: irritation is moderate; clogging risk is low.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- moderate
- Clogging risk
- low
Quick decision guide
Read the cautions before using
Disperse Black 9 can be useful, but watch for some irritation potential.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Disperse Black 9.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
moderateCan bother some users, especially with frequent use, damaged skin, or strong companion ingredients.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
Disperse Black 9 is a synthetic azo dye that belongs to the disperse dye family. It is not water-soluble and is designed to color hair fibers by adhering to the surface or penetrating slightly into the hair shaft.
How it works
In hair color products, Disperse Black 9 works by depositing color onto the hair shaft. It binds to the outer layer of the hair (the cuticle) and, in semi-permanent formulas, may partially penetrate the cortex. The color gradually fades with washing.
Pros
Effective black color
Provides a deep, true black shade that can cover gray or light hair effectively in semi-permanent formulas.
Widely available
Commonly used in many commercial hair dye products, making it easy to find in drugstore and salon brands.
Cons and cautions
Allergic reaction risk
Like many azo dyes, it can cause allergic contact dermatitis, leading to itching, redness, or swelling on the scalp or skin.
Staining
Can stain skin, towels, and clothing during application, requiring careful handling and cleanup.
Best for
- People looking for a temporary or semi-permanent black hair color
- Those who have used similar dyes without reaction
Use caution if
- Individuals with known allergies to hair dyes or a history of contact dermatitis
- People with sensitive or irritated scalps
Usage tips
Safety summary
Disperse Black 9 is generally safe for most people when used as directed in hair dyes, but it carries a moderate risk of skin irritation and allergic reactions. Patch testing is strongly recommended.
Research notes
Studies indicate that Disperse Black 9 can cause allergic contact dermatitis in sensitive individuals, with patch test positivity rates around 1-3% in dermatology clinics. It is considered a moderate sensitizer.
Common label clues
- Typical concentration
- 0.1% to 2% in hair dye formulations
- Regulatory status
- Approved for use in hair dyes in the EU and US within specified concentration limits, but subject to labeling requirements for allergens.
- Common uses
- Hair dye, Temporary hair color, Semi-permanent hair color
- Environmental note
- As a synthetic dye, it may not be biodegradable and can contribute to water pollution if not properly treated in wastewater.
Good to know
- Disperse Black 9 is often listed under its Color Index name (CI 11115) on ingredient labels.
- It is not approved for use in cosmetics in all countries—check local regulations if you are outside the US or EU.
Common questions
What is Disperse Black 9 in beauty products?
Disperse Black 9 is a man-made dye used to give hair a black or dark shade. It is often found in semi-permanent and temporary hair color products. Like many hair dyes, it can sometimes cause skin irritation or allergic reactions, especially if you have sensitive skin or a history of reactions to hair color.
What does Disperse Black 9 do in a beauty product?
In hair color products, Disperse Black 9 works by depositing color onto the hair shaft. It binds to the outer layer of the hair (the cuticle) and, in semi-permanent formulas, may partially penetrate the cortex. The color gradually fades with washing.
Is Disperse Black 9 safe for most people?
Disperse Black 9 is generally safe for most people when used as directed in hair dyes, but it carries a moderate risk of skin irritation and allergic reactions. Patch testing is strongly recommended.
Who should be careful with Disperse Black 9?
Individuals with known allergies to hair dyes or a history of contact dermatitis People with sensitive or irritated scalps
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.