Hydroxypropyltrimonium Hydrolyzed Rice Bran Protein: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 27, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Hydroxypropyltrimonium Hydrolyzed Rice Bran Protein?

Hydroxypropyltrimonium Hydrolyzed Rice Bran Protein is a plant-derived active made from the proteins naturally present in rice bran, the outer layer of rice grains that is usually removed during milling. Chemists take these proteins and break them into smaller pieces, a process called hydrolysis, so they dissolve easily in water. They then attach a gentle, positively charged group known as hydroxypropyltrimonium. This extra charge helps the ingredient bind to hair and skin, which carry a slight negative charge.

Rice has been used for beauty rituals in many Asian cultures for centuries, often in the form of rice water rinses for shiny hair. Modern labs began isolating rice bran proteins in the late 20th century to capture those traditional benefits in a more stable form. Adding the hydroxypropyltrimonium group took the concept a step further by increasing the protein’s ability to stay on the surface of hair or skin after rinsing.

The manufacturing process starts with food-grade rice bran. Proteins are extracted with water, enzymatically hydrolyzed into smaller peptides, purified, then reacted with a quaternary ammonium compound to form the final cationic (positively charged) complex. The result is a clear or slightly hazy liquid that mixes well with both water and mild surfactants, making it easy to add during the cooling phase of cosmetic production.

You will commonly find Hydroxypropyltrimonium Hydrolyzed Rice Bran Protein in shampoos, rinse-off and leave-in conditioners, anti-frizz serums, hair masks, body lotions, lightweight facial moisturizers and after-sun gels. It is popular in products that promise soft touch, easier detangling and a light protective feel without heaviness.

Hydroxypropyltrimonium Hydrolyzed Rice Bran Protein’s Cosmetic Benefits/Uses

This versatile ingredient delivers several performance perks when worked into personal care formulas

  • Antistatic: The positive charge helps neutralize the static electricity that builds up on hair fibers, so strands stay smoother and are less likely to fly away or cling to clothing
  • Hair Conditioning: The small rice peptides can coat the cuticle, filling in rough spots and adding a soft, silky feel. They improve slip during wet combing, reduce breakage and give hair a touch of natural gloss
  • Skin Conditioning: On skin the protein film locks in moisture, leaving a light breathable layer that feels smooth but not greasy. It can also make lotions feel richer without using heavy oils

Who Can Use Hydroxypropyltrimonium Hydrolyzed Rice Bran Protein

This ingredient is generally kind to all skin types including dry, normal, combination and oily. Its light film adds moisture without clogging pores so it suits acne-prone skin as well. Those with very sensitive skin can usually tolerate it because rice proteins are mild, yet anyone with a known grain allergy should be cautious.

Because it comes from plant material and contains no animal by-products, it is suitable for both vegans and vegetarians.

Pregnant or breastfeeding users are not expected to face special risks from products that contain this protein when applied to skin or hair. It does not penetrate deeply or act on hormones. Still, this is not medical advice and anyone who is expecting or nursing should ask their doctor before adding new personal care items just to be safe.

The ingredient does not make skin more sensitive to sunlight so there is no extra need for sunscreen beyond normal daily protection.

Potential Side Effects/Adverse Reactions

Reactions to topical Hydroxypropyltrimonium Hydrolyzed Rice Bran Protein differ from person to person. The points below cover possible issues only. When the ingredient is correctly added to a well-formulated product most people notice no problems.

  • Mild redness or itching in those allergic to rice or grain proteins
  • Scalp or skin irritation if applied in very high concentration or left on for long periods
  • Eye stinging if rinse-off products accidentally run into the eyes
  • Product buildup on hair that may leave strands feeling heavy if not shampooed regularly

If any discomfort, rash or other unwanted effect appears stop using the product and consult a healthcare professional or pharmacist for guidance.

Comedogenic Rating

Rating: 1/5

Hydroxypropyltrimonium Hydrolyzed Rice Bran Protein is highly water-soluble and forms a very thin breathable film that rinses away easily, so it rarely blocks pores or traps oil. The cationic (positively charged) nature helps it adhere lightly to skin yet it does not create an occlusive layer like heavy oils or waxes. For these reasons scientists and formulators generally consider it to have a very low risk of causing comedones.

Suitable for acne-prone or breakout-prone skin, especially in lightweight lotions and gels.

As with any conditioning agent buildup is possible if used in multiple products at once, which could indirectly contribute to congestion in some users, so moderate use is best.

Summary

Hydroxypropyltrimonium Hydrolyzed Rice Bran Protein conditions hair, reduces static and lightly moisturizes skin by forming a micro-thin protein film that smooths rough areas and helps hair strands slide past one another. Its positive charge lets it cling to the negatively charged surface of hair and skin, delivering softness and easy detangling without weight.

While not as famous as keratin or collagen derivatives it has carved out a steady presence in shampoos, leave-in sprays and light facial moisturizers thanks to its plant origin and gentle feel.

Overall it is regarded as safe for most users with a very low allergy or irritation profile. Whenever you try a new product that lists this protein give your skin a chance to adjust by patch testing first so you can be confident it suits you.

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