Ingredient review
Aminoethyl Disulfide Keratin
INCI: Aminoethyl Disulfide Keratin
A modified keratin that bonds to hair to improve strength and smoothness, but results vary by hair type and damage level.
In plain English
Aminoethyl Disulfide Keratin is a lab-modified version of keratin, the protein that naturally makes up your hair. It's designed to attach to damaged areas of the hair shaft, helping to fill in gaps and smooth the cuticle. Think of it as a targeted repair patch for your hair, not a permanent fix but a temporary strengthening treatment.
Quick decision guide
Useful, but context matters
Aminoethyl Disulfide Keratin is generally a lower-concern ingredient when the full formula suits your skin.
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 Aminoethyl Disulfide Keratin.
- 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
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
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
A chemically modified keratin protein where disulfide bonds are introduced to improve binding to hair. It is derived from natural keratin (often from wool or feathers) and then processed to create a more reactive form that can attach to the hair's own keratin.
How it works
When applied to hair, the disulfide groups in this ingredient form new bonds with the hair's own keratin, especially in areas where the hair is damaged or porous. This helps rebuild the hair's internal structure, smooth the cuticle, and reduce breakage. It also forms a thin film on the hair surface for added shine and manageability.
Pros
Targeted repair
Forms bonds specifically with damaged hair areas, providing more precise strengthening than generic proteins.
Improves manageability
Smooths the hair cuticle, reducing frizz and making hair easier to style and comb.
Cons and cautions
Temporary effect
The bonds are not permanent and will gradually wash out, requiring regular reapplication for continued benefits.
Potential buildup
Overuse can lead to protein buildup on the hair, making it feel stiff, dry, or brittle, especially on fine hair.
Best for
- People with chemically treated or heat-damaged hair
- Those seeking temporary strengthening and smoothing
Use caution if
- People with very fine or low-porosity hair (may cause stiffness or buildup)
- Those with protein-sensitive hair (may cause brittleness)
Usage tips
Safety summary
Aminoethyl Disulfide Keratin is considered safe for topical use in hair products at typical concentrations. It has low irritation and comedogenic potential. However, individuals with protein-sensitive hair may experience stiffness or breakage with overuse.
Research notes
Clinical studies and ingredient reviews support the ability of modified keratins to improve hair strength and reduce breakage, especially in damaged hair. Evidence is moderate, with most data coming from manufacturer-sponsored studies and cosmetic science literature.
Common label clues
- Typical concentration
- 0.1% to 2%
- Regulatory status
- Approved for use in cosmetics in the EU, US, and most major markets. No specific restrictions beyond general cosmetic safety requirements.
- Common uses
- Shampoos, Conditioners, Hair masks, Leave-in treatments
- Environmental note
- Keratin is typically sourced as a byproduct of the wool and poultry industries, making it a relatively sustainable ingredient when sourced responsibly.
Good to know
- This ingredient is often found in bond-repairing hair treatments inspired by salon-grade products.
- It works best on clean, damp hair where the cuticle is slightly open for better penetration.
Common questions
What is Aminoethyl Disulfide Keratin in beauty products?
Aminoethyl Disulfide Keratin is a lab-modified version of keratin, the protein that naturally makes up your hair. It's designed to attach to damaged areas of the hair shaft, helping to fill in gaps and smooth the cuticle. Think of it as a targeted repair patch for your hair, not a permanent fix but a temporary strengthening treatment.
What does Aminoethyl Disulfide Keratin do in a beauty product?
When applied to hair, the disulfide groups in this ingredient form new bonds with the hair's own keratin, especially in areas where the hair is damaged or porous. This helps rebuild the hair's internal structure, smooth the cuticle, and reduce breakage. It also forms a thin film on the hair surface for added shine and manageability.
Is Aminoethyl Disulfide Keratin safe for most people?
Aminoethyl Disulfide Keratin is considered safe for topical use in hair products at typical concentrations. It has low irritation and comedogenic potential. However, individuals with protein-sensitive hair may experience stiffness or breakage with overuse.
Who should be careful with Aminoethyl Disulfide Keratin?
People with very fine or low-porosity hair (may cause stiffness or buildup) Those with protein-sensitive hair (may cause brittleness)
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.