Ingredient · Surface Film and Plant Protein
Hydrolysed Soy Protein
INCI · Hydrolyzed Soy Protein
Related names and forms: Hydrolyzed Soya Protein. This list does not indicate synonyms or exact ingredient matches.
Hydrolysed soy protein (INCI: Hydrolyzed Soy Protein) is a water-soluble hydrolysate of protein from soybeans (Glycine soja), broken down enzymatically or chemically into small peptides and amino acids. Its plant origin makes it common in formulas favouring plant proteins. Its appeal comes from combining moisture attraction, a humectant-like property, with a thin film on hair and skin. In hair care, these are assessed together for body, conditioning, softness and a more manageable appearance, in shampoos, conditioners and masks. Skincare uses it for a moist, smooth surface feel. An important limit: its effects are superficial and temporary. It provides temporary body and feel without permanently changing strand diameter or skin structure. On safety, cosmetic ingredient assessment groups have noted that topical cosmetic use is a different context from dietary soy sensitivity, although patch testing remains measured for known skin sensitivity. As a mixture of variable molecular weight, it has no single CID record; its reference framework uses general source families. Klaris considers it alongside moisture-protein balance and the complete formula.
i. Cosmetic Functions
Frequently Discussed Effects
The following headings summarise areas of effect frequently discussed in the literature; visible results in each area require regular use and a suitable formula.
Moisture + Film Balance
Combines water binding with surface-film properties, contributing to a moisturised feel and the appearance of body.
Hair Body and Conditioning
A film on the strand supports temporary body, softness and a more manageable appearance.
Skin Surface Feel
Used in skincare for a moist, smooth surface feel.
Mechanism
What Happens Within the Skin?
The following points summarise mechanisms from dermocosmetic literature in plain English. Klaris presents them as background information to help readers understand the context, not as medical claims.
Step 1
Plant Peptide and Amino Acid Mixture
Soy protein broken into small, water-soluble pieces; a mixture of variable molecular weight.
Step 2
Moisture + Surface Film
Combines water binding and surface-film formation, contributing to body, conditioning and feel.
Step 3
Temporary Surface Effects
Effects remain temporary and at the surface, without permanently changing strand diameter or skin structure.
ii. Role in the Formula
How Is It Read on a Label?
Hydrolysed soy protein is the water-soluble form of soy protein broken into low-molecular-weight peptides and amino acids, combining moisture attraction and surface-film formation. Shampoos, conditioners and masks use it for body, conditioning and manageability; moisturisers and serums use it for skin surface feel. Effects are superficial and temporary. Its plant origin makes it common in formulas favouring plant proteins.
Typical Concentration Range
0.5% - 5% (depending on formula context)
Ingredient Family
Proteins
iii. Sensitivity Advisory
A Note on Extra Care in Context
Generally well tolerated in cosmetics; topical cosmetic use is a different context from dietary soy sensitivity. With known skin sensitivity, patch testing a new product is a measured approach.
A sensitivity advisory is not an instruction for use; where individual health circumstances, pregnancy or known sensitivities are involved, discussing the decision with your doctor may be a more contextual approach.
Scientific Basis
Sources and Their Scope
The following headings indicate areas of research; they are not citations of a specific publication or confirmation that every statement on this page has been verified. The links provided should be read with their individual scope in mind.
- International INCI / CosIng database
- Dermocosmetic research publications
- Formulation chemistry guides
Starting Points for Independent Research
These links lead to official databases and serve as starting points for searches.
iv. Related Ingredients
Ingredients Often Read Together
v. Proteins Family
Other Ingredients in the Same Family
Explore ingredients in the same functional family to deepen your reading of formulas.
vi. Academy · Related Reading
For a Closer Look
6 Min Read
How to Read an INCI List on a Hair Product
Familiar ingredient families in shampoo, conditioner and masks, and how the context of the same list changes with your Hair Identity.
6 Min Read
Fine and Thick Hair: How to Read the Ingredients
Strand thickness, tolerance for weight and the appearance of volume: key ingredient families for fine and thick strands.
6 Min Read
How to Read Natural and Organic Labels
The differences between label terminology, certification systems and the context of a formula.
Klaris · Example Analyses
How Does Hydrolysed Soy Protein Feature
in Your Products?
Explore product examples to see the ingredient list, general assessment and match score that changes with the example profile together.
Masked products and example profiles, not a personal analysis. Profile matching in the app is part of Klaris Premium. The app is currently available in Turkish. An English version is in preparation.