Ingredient review
Hydroxyethylaminophenol
INCI: 2-METHYL-5-HYDROXYETHYLAMINOPHENOL
A synthetic colorant used in hair dyes; generally safe when used as directed but may cause irritation in sensitive individuals.
In plain English
This ingredient is a synthetic compound used in hair dyes to help create and stabilize color. It works by reacting with other dye ingredients to form larger color molecules that get trapped inside the hair shaft. While it's considered safe for most people when used in rinse-off hair color products, it can sometimes cause skin irritation or allergic reactions, especially on sensitive scalps.
Quick decision guide
Useful, but context matters
Hydroxyethylaminophenol 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 Hydroxyethylaminophenol.
- 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
2-Methyl-5-hydroxyethylaminophenol is a synthetic aromatic amine used as a colorant intermediate in oxidative hair dye formulations. It is not a natural ingredient and is produced through chemical synthesis.
How it works
In oxidative hair dyes, this ingredient reacts with hydrogen peroxide and other dye precursors to form larger colored molecules. These molecules become trapped within the hair cortex, providing long-lasting color that resists washing.
Pros
Effective colorant
Helps produce a wide spectrum of hair colors, from natural tones to vibrant shades, with good staying power.
Industry standard
Widely used and tested in commercial hair dyes, with established safety profiles when used as directed.
Cons and cautions
Irritation risk
Can cause skin or scalp irritation, especially in people with sensitive skin or those who dye hair frequently.
Allergic potential
May trigger allergic reactions in individuals sensitive to aromatic amines; a patch test is recommended before use.
Best for
- People looking for permanent or semi-permanent hair color
- Those without known sensitivity to hair dye ingredients
Use caution if
- Individuals with known allergies to para-phenylenediamine (PPD) or similar aromatic amines
- People with sensitive or irritated scalps
Usage tips
Safety summary
Generally recognized as safe for use in rinse-off hair dye products at typical concentrations. However, it carries a moderate risk of skin irritation and allergic contact dermatitis, particularly for individuals with pre-existing sensitivities. The Cosmetic Ingredient Review (CIR) panel has evaluated similar aminophenol compounds and found them safe when formulated to be non-irritating.
Research notes
Studies on aminophenol derivatives indicate low acute toxicity and no significant genotoxicity in standard assays. However, some aromatic amines have been associated with allergic reactions. Regulatory bodies have set safe concentration limits based on available data.
Common label clues
- Typical concentration
- 0.1% to 2% in hair dye products
- Regulatory status
- Approved for use in cosmetic hair dyes in the EU, US, and many other regions, subject to concentration limits and labeling requirements. In the EU, it is listed in Annex III of the Cosmetics Regulation.
- Common uses
- Hair dyes, Oxidative hair color formulations
- Environmental note
- Synthetic hair dye ingredients can contribute to water pollution; proper disposal of unused dye and rinsing water is recommended.
Good to know
- This ingredient is typically found in permanent and demi-permanent hair dyes, not in temporary rinses or shampoos.
- It is often listed alongside other dye intermediates like p-phenylenediamine or resorcinol in hair color formulas.
Common questions
What is Hydroxyethylaminophenol in beauty products?
This ingredient is a synthetic compound used in hair dyes to help create and stabilize color. It works by reacting with other dye ingredients to form larger color molecules that get trapped inside the hair shaft. While it's considered safe for most people when used in rinse-off hair color products, it can sometimes cause skin irritation or allergic reactions, especially on sensitive scalps.
What does Hydroxyethylaminophenol do in a beauty product?
In oxidative hair dyes, this ingredient reacts with hydrogen peroxide and other dye precursors to form larger colored molecules. These molecules become trapped within the hair cortex, providing long-lasting color that resists washing.
Is Hydroxyethylaminophenol safe for most people?
Generally recognized as safe for use in rinse-off hair dye products at typical concentrations. However, it carries a moderate risk of skin irritation and allergic contact dermatitis, particularly for individuals with pre-existing sensitivities. The Cosmetic Ingredient Review (CIR) panel has evaluated similar aminophenol compounds and found them safe when formulated to be non-irritating.
Who should be careful with Hydroxyethylaminophenol?
Individuals with known allergies to para-phenylenediamine (PPD) or similar aromatic amines 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.