Ingredient review

Hydrolyzed Soy Protein Surfactant

INCI: SODIUM/TEA-UNDECYLENOYL HYDROLYZED SOY PROTEIN

A gentle, protein-based surfactant that cleanses without stripping the skin, making it ideal for sensitive or dry skin types.

beautyskincarecleansing

In plain English

This ingredient is a mild cleanser made by combining soy protein with a fatty acid from castor oil. It helps remove dirt and oil from your skin and hair without causing dryness or irritation, and it leaves a soft, conditioned feel.

Review score

Safety, usefulness, and evidence

4.0Good
4.0/ 5

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
How reviews are scored

Quick decision guide

Useful, but context matters

Hydrolyzed Soy Protein Surfactant 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.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Hydrolyzed Soy Protein Surfactant.
  2. Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
  3. 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

low

Less likely to sting, burn, or bother most users, though sensitive skin can still react.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

moderate

There is useful support, but formula details and claim strength still matter.

What it is

A semi-synthetic surfactant created by reacting hydrolyzed soy protein with undecylenic acid (derived from castor oil) and neutralizing it with sodium and TEA salts. It is a mild, amphoteric-like cleansing agent.

How it works

It works by reducing the surface tension of water, allowing oils and dirt to be rinsed away. The protein portion helps bind moisture to the skin and hair, providing conditioning benefits while cleansing.

Pros

Very gentle on skin

Unlike harsh sulfates, this surfactant cleanses without stripping the skin's natural moisture barrier, making it suitable for sensitive or compromised skin.

Conditioning effect

The hydrolyzed soy protein leaves a light film on skin and hair, improving softness and manageability after washing.

Cons and cautions

Lower foam volume

It produces a modest lather compared to sodium lauryl sulfate, which may feel less satisfying to those who associate foam with cleanliness.

Potential for TEA sensitivity

Triethanolamine (TEA) can be irritating for some individuals, especially in leave-on products or at high concentrations.

Best for

  • People with dry or sensitive skin
  • Those looking for a mild, everyday cleanser

Use caution if

  • Individuals with known soy allergies (rare in topical use)
  • Those who prefer high-foaming cleansers

Usage tips

Use in rinse-off products like cleansers and shampoos for best results.
Pair with a secondary surfactant like cocamidopropyl betaine to boost foam if desired.

Safety summary

Generally recognized as safe for topical use. Low irritation and comedogenic potential. Rare allergic reactions possible in individuals with soy allergy, though topical exposure is minimal.

Research notes

Studies on hydrolyzed soy protein surfactants show they are mild to the skin and provide conditioning benefits. Evidence is primarily from cosmetic chemistry literature and safety assessments rather than large clinical trials.

Common label clues

Typical concentration
1–10%
Regulatory status
Approved for use in cosmetics in the US (FDA) and EU (CosIng) with no specific restrictions at typical concentrations.
Common uses
Facial cleansers, Body washes, Shampoos, Conditioners
Environmental note
Derived from renewable plant sources (soy and castor oil) and is biodegradable, making it a more sustainable choice than petroleum-based surfactants.

Good to know

  • This ingredient is often listed as part of a 'protein surfactant' blend in natural or sensitive-skin formulas.
  • It is biodegradable and considered more environmentally friendly than some traditional surfactants.

Common questions

What is Hydrolyzed Soy Protein Surfactant in beauty products?

This ingredient is a mild cleanser made by combining soy protein with a fatty acid from castor oil. It helps remove dirt and oil from your skin and hair without causing dryness or irritation, and it leaves a soft, conditioned feel.

What does Hydrolyzed Soy Protein Surfactant do in a beauty product?

It works by reducing the surface tension of water, allowing oils and dirt to be rinsed away. The protein portion helps bind moisture to the skin and hair, providing conditioning benefits while cleansing.

Is Hydrolyzed Soy Protein Surfactant safe for most people?

Generally recognized as safe for topical use. Low irritation and comedogenic potential. Rare allergic reactions possible in individuals with soy allergy, though topical exposure is minimal.

Who should be careful with Hydrolyzed Soy Protein Surfactant?

Individuals with known soy allergies (rare in topical use) Those who prefer high-foaming cleansers

Research sources

CosIng - European CommissionOpenPubMed - Protein Surfactants in CosmeticsOpenPersonal Care Council - Safety AssessmentOpen

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.