Ingredient review
Sodium Stearoyl Lactalbumin
INCI: Sodium Stearoyl Lactalbumin
A mild, protein-derived surfactant that cleanses gently and helps maintain skin's moisture barrier, ideal for sensitive or dry skin.
In plain English
Sodium Stearoyl Lactalbumin is a gentle cleansing ingredient made by combining milk protein (lactalbumin) with stearic acid, a fatty acid found in shea butter and cocoa butter. It works like a mild soap but is much less drying. It helps remove dirt and oil from your skin while leaving it feeling soft and smooth, not tight or stripped. Because it's derived from milk, it also has some conditioning properties that can help maintain your skin's natural moisture barrier.
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 Lactalbumin 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 Lactalbumin.
- 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 lactalbumin (a milk protein) with stearic acid (a fatty acid) and neutralizing with sodium hydroxide. It belongs to the class of amino acid-based surfactants, known for their mildness and compatibility with sensitive skin.
How it works
In a cosmetic product, Sodium Stearoyl Lactalbumin acts as a surfactant, meaning it helps water mix with oil and dirt so they can be rinsed away. Its protein component also allows it to deposit a thin conditioning film on the skin or hair, reducing friction and leaving a soft feel. Unlike harsher sulfates, it cleans without disrupting the skin's lipid barrier significantly.
Pros
Exceptionally gentle cleansing
Unlike sodium lauryl sulfate, this ingredient cleans without stripping the skin's natural oils, making it ideal for daily use on sensitive or dry skin.
Conditioning benefits
The milk protein component leaves a subtle conditioning film that helps skin feel soft and smooth after washing, reducing the need for additional moisturizers.
Cons and cautions
Not vegan-friendly
Since it is derived from milk protein, it is unsuitable for those following a vegan lifestyle or avoiding animal-derived ingredients.
Lower lather volume
It produces a less foamy lather compared to traditional sulfate cleansers, which some users may perceive as less effective even though it cleans just as well.
Best for
- People with dry, sensitive, or eczema-prone skin looking for a gentle cleanser
- Those who prefer mild, protein-based ingredients over harsh sulfates
Use caution if
- Individuals with a known allergy or intolerance to milk proteins or dairy
Usage tips
Safety summary
Sodium Stearoyl Lactalbumin is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential, making it suitable for sensitive skin. However, individuals with milk protein allergies should avoid it.
Research notes
While specific studies on Sodium Stearoyl Lactalbumin are limited, the broader class of amino acid and protein-based surfactants is well-documented for mildness and skin compatibility. Its safety is supported by its use in many gentle cleansers and by regulatory acceptance.
Common label clues
- Typical concentration
- 1-5% in rinse-off products
- Regulatory status
- Approved for use in cosmetics in the EU, US, and other major markets. No specific restrictions beyond general cosmetic safety requirements.
- Common uses
- Cleansers, Facial washes, Body washes, Shampoos
- Environmental note
- Derived from renewable milk protein and stearic acid (often from plant sources), it is biodegradable and has a lower environmental impact compared to many synthetic surfactants.
Good to know
- Sodium Stearoyl Lactalbumin is considered biodegradable and more environmentally friendly than some petroleum-based surfactants.
- It is often found in 'milk protein' cleansers marketed for their soothing and nourishing properties.
Common questions
What is Sodium Stearoyl Lactalbumin in beauty products?
Sodium Stearoyl Lactalbumin is a gentle cleansing ingredient made by combining milk protein (lactalbumin) with stearic acid, a fatty acid found in shea butter and cocoa butter. It works like a mild soap but is much less drying. It helps remove dirt and oil from your skin while leaving it feeling soft and smooth, not tight or stripped. Because it's derived from milk, it also has some conditioning properties that can help maintain your skin's natural moisture barrier.
What does Sodium Stearoyl Lactalbumin do in a beauty product?
In a cosmetic product, Sodium Stearoyl Lactalbumin acts as a surfactant, meaning it helps water mix with oil and dirt so they can be rinsed away. Its protein component also allows it to deposit a thin conditioning film on the skin or hair, reducing friction and leaving a soft feel. Unlike harsher sulfates, it cleans without disrupting the skin's lipid barrier significantly.
Is Sodium Stearoyl Lactalbumin safe for most people?
Sodium Stearoyl Lactalbumin is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential, making it suitable for sensitive skin. However, individuals with milk protein allergies should avoid it.
Who should be careful with Sodium Stearoyl Lactalbumin?
Individuals with a known allergy or intolerance to milk proteins or dairy
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.