Ingredient review
Sodium Stearoyl Hydrolyzed Silk
INCI: Sodium Stearoyl Hydrolyzed Silk
A mild, silk-based cleansing agent that helps clean skin and hair without causing dryness or irritation.
In plain English
Sodium Stearoyl Hydrolyzed Silk is a gentle cleanser made by combining stearic acid (a fatty acid from plants or animals) with hydrolyzed silk (silk proteins broken into smaller pieces). It works like a mild soap, helping to remove dirt and oil while leaving skin feeling soft and smooth. Because it's derived from silk, it's known for being less harsh than many traditional cleansers.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- semi synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Sodium Stearoyl Hydrolyzed Silk 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 Sodium Stearoyl Hydrolyzed Silk.
- 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 semi-synthetic surfactant created by reacting stearic acid with hydrolyzed silk proteins. It is often used in mild, sulfate-free cleansers.
How it works
It reduces the surface tension of water, allowing it to mix with oils and dirt so they can be rinsed away. The silk protein component also deposits a thin, conditioning film on the skin or hair, which helps reduce friction and leaves a smooth feel.
Pros
Very gentle on skin
Unlike harsher sulfates, this ingredient cleans without stripping the skin's moisture barrier, making it ideal for sensitive or dry skin types.
Adds softness and conditioning
The silk protein component leaves a smooth, silky feel on skin and hair, reducing dryness and improving texture after washing.
Cons and cautions
Lower foam production
It produces a creamy, low-foam lather rather than big bubbles, which some users may find less satisfying or effective.
Higher cost
Because it's derived from silk proteins, it is typically more expensive than common surfactants, which can raise the price of products containing it.
Best for
- People with dry or sensitive skin looking for a mild cleanser
- Anyone wanting a sulfate-free, gentle cleansing option
Use caution if
- Those who prefer a rich, foamy lather may find it less satisfying
Usage tips
Safety summary
Sodium Stearoyl Hydrolyzed Silk is considered safe for use in cosmetics. It has low irritation and comedogenic potential, making it suitable for sensitive skin. No significant safety concerns have been reported in the literature.
Research notes
Research on this specific ingredient is limited, but it is structurally similar to other amino acid-based surfactants that are well-documented as mild and skin-friendly. The silk protein component is known for its moisturizing and conditioning properties.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US (FDA) and EU (CosIng) with no known restrictions at typical concentrations.
- Common uses
- Cleansers, Shampoos, Body washes, Facial washes
- Environmental note
- Silk is a natural protein fiber, but the production process involves chemical modification. Biodegradability is expected to be moderate.
Good to know
- Hydrolyzed silk means the silk proteins have been broken down into smaller peptides so they can better penetrate and condition the skin.
- This ingredient is often found in sulfate-free and 'low-poo' hair care products.
Common questions
What is Sodium Stearoyl Hydrolyzed Silk in beauty products?
Sodium Stearoyl Hydrolyzed Silk is a gentle cleanser made by combining stearic acid (a fatty acid from plants or animals) with hydrolyzed silk (silk proteins broken into smaller pieces). It works like a mild soap, helping to remove dirt and oil while leaving skin feeling soft and smooth. Because it's derived from silk, it's known for being less harsh than many traditional cleansers.
What does Sodium Stearoyl Hydrolyzed Silk do in a beauty product?
It reduces the surface tension of water, allowing it to mix with oils and dirt so they can be rinsed away. The silk protein component also deposits a thin, conditioning film on the skin or hair, which helps reduce friction and leaves a smooth feel.
Is Sodium Stearoyl Hydrolyzed Silk safe for most people?
Sodium Stearoyl Hydrolyzed Silk is considered safe for use in cosmetics. It has low irritation and comedogenic potential, making it suitable for sensitive skin. No significant safety concerns have been reported in the literature.
Who should be careful with Sodium Stearoyl Hydrolyzed Silk?
Those who prefer a rich, foamy lather may find it less satisfying
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.