Hydrolyzed soy protein is a soy-derived protein broken into smaller peptides and amino acids, used in skincare and haircare for its moisturizing, conditioning, and film-forming properties that can temporarily improve skin smoothness and hair manageability. It is valued for its water-binding capacity and substantivity to skin and hair surfaces.
| Reported effect | How often | Notes |
|---|---|---|
Allergic contact dermatitis | Rare | Possible in individuals with soy sensitivity; presents as redness, itching, or rash. |
Skin irritation | Uncommon | Mild transient stinging or irritation, more likely in sensitive or compromised skin. |
Contact urticaria | Very rare | Hives upon application reported in soy-allergic individuals. |
Frequencies reflect typical cosmetic use reported in the literature, not a guarantee for your skin.
Peer-reviewed papers on this ingredient, via PubMed.