Ingredient review
AMP-Isostearoyl Hydrolyzed Keratin
INCI: AMP-ISOSTEAROYL HYDROLYZED KERATIN
A gentle, modified keratin that helps strengthen and protect hair and nails without irritation.
In plain English
This is a protein derived from keratin (the same protein that makes up your hair and nails) that has been chemically modified to be more stable and effective in products. It's often used in shampoos and conditioners to help repair damage, reduce breakage, and add shine. Because it's modified, it can stick to hair better than plain keratin, providing longer-lasting benefits.
Quick decision guide
Useful, but context matters
AMP-Isostearoyl Hydrolyzed 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 AMP-Isostearoyl Hydrolyzed 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
AMP-Isostearoyl Hydrolyzed Keratin is a semi-synthetic ingredient created by combining hydrolyzed keratin (broken-down keratin protein) with isostearic acid (a fatty acid) and AMP (a pH adjuster). This modification makes the protein more lipophilic (oil-loving), allowing it to adhere better to the hair shaft and resist rinsing away.
How it works
When applied to hair or nails, this ingredient forms a thin, flexible film that fills in gaps in the cuticle or nail plate. The fatty acid part helps it bind to the surface, while the protein part provides structural support. This reduces porosity, smooths the surface, and helps prevent future damage from brushing, heat styling, or environmental stress.
Pros
Strengthens hair
Helps repair damage from chemical treatments and heat styling by filling in gaps in the hair cuticle.
Improves nail health
Can be used in nail treatments to reduce peeling and brittleness, making nails stronger over time.
Cons and cautions
Potential buildup
With frequent use, especially in leave-in products, it can accumulate on hair, leading to stiffness or dullness.
Not for all hair types
Very fine or low-porosity hair may not benefit as much and could feel weighed down or greasy.
Best for
- People with damaged, color-treated, or heat-styled hair
- Those with brittle or peeling nails
Use caution if
- Individuals with very fine or low-porosity hair who may experience buildup
- Anyone with a known allergy to keratin or wool (lanolin)
Usage tips
Safety summary
AMP-Isostearoyl Hydrolyzed Keratin is considered safe for topical use. It has low irritation and comedogenic potential. However, individuals with wool allergies should check the source of the keratin.
Research notes
Studies on hydrolyzed keratin show it can improve hair strength and moisture retention. The modified version (AMP-isostearoyl) is designed for better adhesion, but specific clinical data on this exact form is limited. Most evidence comes from ingredient supplier studies and general keratin research.
Common label clues
- Typical concentration
- 0.1% to 2%
- Regulatory status
- Approved for use in cosmetics in the US (FDA) and EU (CosIng) with no known restrictions at typical concentrations.
- Common uses
- Shampoos, Conditioners, Hair masks, Leave-in treatments, Nail treatments
- Environmental note
- Keratin is typically sourced from animal by-products (wool, feathers, horns). Look for plant-based alternatives if you prefer vegan options.
Good to know
- This ingredient is often listed near the end of an ingredient list because it's used in low concentrations.
- It is not the same as pure keratin; the modification makes it more effective in cosmetic formulas.
Common questions
What is AMP-Isostearoyl Hydrolyzed Keratin in beauty products?
This is a protein derived from keratin (the same protein that makes up your hair and nails) that has been chemically modified to be more stable and effective in products. It's often used in shampoos and conditioners to help repair damage, reduce breakage, and add shine. Because it's modified, it can stick to hair better than plain keratin, providing longer-lasting benefits.
What does AMP-Isostearoyl Hydrolyzed Keratin do in a beauty product?
When applied to hair or nails, this ingredient forms a thin, flexible film that fills in gaps in the cuticle or nail plate. The fatty acid part helps it bind to the surface, while the protein part provides structural support. This reduces porosity, smooths the surface, and helps prevent future damage from brushing, heat styling, or environmental stress.
Is AMP-Isostearoyl Hydrolyzed Keratin safe for most people?
AMP-Isostearoyl Hydrolyzed Keratin is considered safe for topical use. It has low irritation and comedogenic potential. However, individuals with wool allergies should check the source of the keratin.
Who should be careful with AMP-Isostearoyl Hydrolyzed Keratin?
Individuals with very fine or low-porosity hair who may experience buildup Anyone with a known allergy to keratin or wool (lanolin)
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.