What Is Pg-Hydrolyzed Keratin?
Pg-Hydrolyzed Keratin is a modified form of keratin, the tough protein that makes up human hair, nails and the outer layer of skin. In this ingredient the large keratin molecules are first broken down into smaller fragments through hydrolysis. These fragments are then reacted with propylene glycol to create 2-hydroxypropyl derivatives, which are water soluble and easier for cosmetic formulas to handle. Keratin itself is usually sourced from wool, feathers or other keratin-rich by-products of the textile or food industries, giving new life to materials that would otherwise be discarded.
The beauty world began experimenting with hydrolyzed keratin in the 1970s, when chemists discovered that smaller protein pieces could cling to damaged hair and skin. Adding propylene glycol came later, allowing the ingredient to mix smoothly into modern water-based formulas. Production starts with cleaning and grinding the raw keratin source, followed by controlled acid or enzymatic hydrolysis to cut the protein into peptides. After neutralizing and filtering, the peptides are reacted with propylene glycol, purified and spray-dried into a fine powder or left as a clear liquid concentrate.
You will spot Pg-Hydrolyzed Keratin in rinse-off and leave-on hair products such as shampoos, conditioners, masks and styling creams. It also appears in skin care like moisturizers, anti-aging serums, hand creams and after-sun treatments where a boost of protective protein is welcome.
Pg-Hydrolyzed Keratin’s Cosmetic Benefits/Uses
This ingredient is prized for the way it improves how products feel and perform on both hair and skin.
- Hair conditioning: The small keratin peptides attach to rough spots along the hair shaft, filling in gaps and smoothing the cuticle. This can make hair feel softer, look shinier and become easier to detangle while helping reduce breakage from brushing or heat styling.
- Skin conditioning: On the skin, the ingredient forms a light protective film that helps hold moisture in and supports the natural barrier. Regular use can leave skin feeling smoother and more supple while reducing the appearance of dryness or flakiness.
Who Can Use Pg-Hydrolyzed Keratin
Pg-Hydrolyzed Keratin is generally well tolerated by most skin types, including normal, dry and sensitive skin, thanks to its mild film-forming nature and low likelihood of clogging pores. Oily or acne-prone complexions can also use it because the ingredient itself is non-comedogenic, although the overall formula still matters. Those with a known allergy to wool, feathers or other animal proteins should proceed with caution since the keratin source is animal derived.
Because Pg-Hydrolyzed Keratin comes from animal by-products it is not suitable for vegans and may not meet the preferences of strict vegetarians. If plant-based hair or skin care is a priority, look for formulas that rely on vegetable proteins such as soy or wheat instead.
Current safety data show no specific risks for pregnant or breastfeeding women when Pg-Hydrolyzed Keratin is used topically and in the small concentrations found in cosmetics. That said this is not medical advice and anyone who is pregnant or nursing should check with a healthcare professional before adding new products to a routine.
The ingredient does not increase photosensitivity so there is no special sun exposure warning beyond the usual daily SPF recommendation. It is also color-safe for dyed hair and compatible with most common cosmetic actives.
Potential Side Effects/Adverse Reactions
Reactions to Pg-Hydrolyzed Keratin vary from person to person. The effects listed below are possible although they are uncommon when the ingredient is used at cosmetic concentrations and formulated correctly.
- Allergic contact dermatitis – redness, itching or rash in individuals sensitive to animal keratin or propylene glycol
- Mild eye irritation – stinging if the product accidentally enters the eyes, usually temporary
- Scalp or skin buildup – a heavy or stiff feel if highly concentrated proteins layer up over time, more likely with leave-on hair products
- Exacerbation of existing eczema – rarely, the film-forming property may trap heat or sweat and aggravate flare-prone skin
- Unwanted hair texture change – coarse or protein-sensitive hair can feel brittle if exposed to excess protein without enough moisture
If any discomfort, irritation or other adverse change occurs stop using the product and consult a healthcare professional for guidance.
Comedogenic Rating
Rating: 1 / 5 (very low)
Pg-Hydrolyzed Keratin is a water-soluble protein derivative with little to no oil content, so it has minimal tendency to block pores. Its propylene glycol side chain also keeps it light and easy to rinse, preventing the heavy film that can lead to congestion. For these reasons the ingredient earns a low score of 1.
Suitable for acne-prone or breakout-prone skin in most cases.
As with any formula, the overall product base matters more than the single ingredient. Rich creams that contain Pg-Hydrolyzed Keratin can still feel heavy if they rely on occlusive oils or waxes.
Summary
Pg-Hydrolyzed Keratin conditions hair and skin by latching tiny keratin peptides onto damaged areas, smoothing rough cuticles, reinforcing the skin barrier and creating a light protective film that locks in moisture. Its water-friendly structure lets it blend seamlessly into shampoos, conditioners, masks, leave-in sprays, serums and lotions.
The ingredient enjoys moderate popularity. It is a staple in many salon-style hair treatments yet is less talked about than buzzier actives like hyaluronic acid or peptides meant for anti-aging. Still, formulators keep reaching for it because it delivers visible softness and shine without much fuss.
Topically applied Pg-Hydrolyzed Keratin is considered safe for the vast majority of users, with only rare reports of irritation or allergy. As with any new cosmetic it is wise to do a small patch test to rule out personal sensitivities before full use.