Hydrolyzed Keratin Pg-Propylmethylsilanediol: 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 Hydrolyzed Keratin Pg-Propylmethylsilanediol?

Hydrolyzed Keratin Pg-Propylmethylsilanediol is a blend of broken-down keratin protein and a silicone-based carrier. The keratin usually comes from wool or other keratin-rich sources that are cleaned, treated with enzymes or acids, then chopped into tiny peptides so they can dissolve in water. These peptides are reacted with propylene glycol and a silanol compound to form a stable complex that spreads easily and clings to hair or skin.

The idea of mixing proteins with silicones took off in the late 1990s when formulators wanted the softness of silicone without losing the strength that proteins give. By bonding the two, they created an ingredient that could condition while adding a light protective film. Today it is made in specialty labs that control pH and temperature to link the keratin fragments with the silanol group, then filter and dry the final powder or keep it as a clear liquid.

You will spot Hydrolyzed Keratin Pg-Propylmethylsilanediol in rinse-off and leave-in hair masks, conditioners, color-protect formulas, styling creams, anti-frizz serums, moisturizing face creams, firming lotions and some after-shave balms.

Hydrolyzed Keratin Pg-Propylmethylsilanediol’s Cosmetic Benefits/Uses

This dual-action ingredient supports both hair and skin care routines.

  • Hair conditioning: The keratin peptides fill in weak spots along the hair shaft, while the silanol part forms a thin shield that boosts shine and cuts down static. Hair feels smoother looks glossier and resists breakage after brushing or heat styling.
  • Skin conditioning: On skin the small keratin fragments bind water and sit inside fine lines giving a plump hydrated look. The light silicone layer reduces rough texture so skin feels soft with a satiny finish.

Who Can Use Hydrolyzed Keratin Pg-Propylmethylsilanediol

This ingredient suits most skin types including dry, normal, combination and moderately oily skin because its light silicone film does not suffocate the surface and the keratin peptides draw in moisture. Very oily or acne prone skin may find the added film a bit heavy which could feel greasy or contribute to clogged pores if layered with thick products.

Hair wise it works across the board from fine to coarse strands with special value for damaged color treated or heat styled hair that needs strength and smoothness.

Keratin is typically sourced from wool or other animal by products so formulas containing Hydrolyzed Keratin Pg-Propylmethylsilanediol are not suitable for vegans and may be declined by strict vegetarians. A few specialty suppliers offer plant based or bio-fermented keratin alternatives but those are labeled differently.

Topical use during pregnancy or while breastfeeding is generally viewed as low risk because the large peptide molecules stay on the surface rather than entering the bloodstream. This is not medical advice and anyone who is pregnant or nursing should ask a healthcare professional before adding new products just to be safe.

The ingredient does not make skin more sensitive to sunlight and can be worn during the day without added risk of sunburn. It plays well with common actives like niacinamide or panthenol and does not destabilize hair dyes or perms.

Potential Side Effects/Adverse Reactions

Responses to Hydrolyzed Keratin Pg-Propylmethylsilanediol vary from person to person. The points below cover possible reactions but most users experience none of them when the ingredient is correctly formulated and used as directed.

  • Mild redness or itching on highly sensitive skin
  • Allergic response in individuals allergic to wool or animal proteins
  • Scalp or skin buildup that leaves a greasy feel if the product is not rinsed thoroughly
  • Temporary stiffness or brittleness in hair when combined with other high protein products causing “protein overload”
  • Clogged pores or minor breakouts in acne prone skin if heavy leave-on formulas are applied to the face

If any irritation or unwanted reaction develops discontinue use and seek guidance from a qualified healthcare professional.

Comedogenic Rating

Rating: 1/5

Hydrolyzed Keratin Pg-Propylmethylsilanediol is mostly made of water-soluble keratin peptides coupled with a lightweight silanol group. It does not act like a heavy oil or wax, so it rarely blocks pores. The silicone segment can leave a thin film that might feel slick on very oily skin, yet it remains breathable and rinses off easily which keeps the clogging risk low.

For acne-prone users this ingredient is generally considered suitable, though lighter formulas or rinse-off products are preferred.

Products that layer several film-forming agents could raise the occlusive load which may bump up the chance of congestion, so pay attention to the full ingredient list.

Summary

Hydrolyzed Keratin Pg-Propylmethylsilanediol works as a hair and skin conditioner. The fragmented keratin slips into tiny gaps along the hair cuticle or the outer skin layer to add strength and water binding while the silanol part forms a smooth protective sheen that boosts softness and shine.

It shows up most often in salon-style hair masks, bond builders and a handful of high-end face creams. Outside of pro hair care it is still a niche additive, so casual shoppers may not see it on every shelf yet formulators value its dual benefit profile.

Safety data are favorable with low irritation and a minimal comedogenic score. Allergies are rare and mainly linked to wool sensitivity. As with any new cosmetic it is wise to patch test first to make sure your skin or scalp agree with the full formula.

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