Soy Protein
SOY PRO-teen
What Is Soy Protein?
A plant-derived protein extracted from soybeans. It provides medium-weight strengthening and conditioning, and contains amino acids similar to those found in human hair keratin.
Source: Soybeans (Glycine soja/max)
Origin: Natural
Also known as: Hydrolyzed Soy Protein, Glycine Soja Protein
What Does Soy Protein Do to Your Hair?
Strengthens hair by supplementing its natural amino acid content. Forms a protective film that improves moisture retention, adds body, and enhances shine. Also provides antioxidant benefits from soy isoflavones.
Best For
Damaged hair, color-treated hair, normal to thick hair, aging hair
Not Recommended For
Protein-sensitive hair, soy allergy sufferers
Concentration Matters
1-5% in hair products
Hair Type Compatibility
Method Compatibility
Safety & Regulation
Generally safe for cosmetic use. Those with soy allergies should exercise caution, though topical application is typically lower risk than ingestion. Phytoestrogen content is negligible in hair products.
FDA Status: Generally Recognized As Safe
FDA permits use in cosmetics. Soy is a recognized allergen for labeling purposes.
EWG Score: 2/10
HairAide Verdict
A solid medium-weight protein for hair strengthening. Good amino acid profile for hair repair. If you have a soy allergy, opt for rice or oat protein instead.
Products That Contain Soy Protein
Strengthening shampoos, conditioners, protein treatments, hair masks
Alternatives to Soy Protein
If you want to avoid Soy Protein, look for products with these ingredients instead:
Rice Protein, Oat Protein, Hydrolyzed Wheat Protein, Hydrolyzed Keratin
Frequently Asked Questions
Yes, Soy Protein has a safety rating of 8/10 and is generally considered safe for use in hair products. Generally safe for cosmetic use. Those with soy allergies should exercise caution, though topical application is typically lower risk than ingestion. Phytoestrogen content is negligible in hair products.
Soy Protein is CG-method approved and is generally considered safe for curly hair.
Yes, Soy Protein is approved for the Curly Girl method.
Some alternatives to Soy Protein include: Rice Protein, Oat Protein, Hydrolyzed Wheat Protein, Hydrolyzed Keratin
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