Ingredient review
Cystine Bis-PG-Propyl Silanetriol
INCI: Cystine Bis-PG-Propyl Silanetriol
A hybrid ingredient that combines amino acids with silicon to help strengthen hair and support skin barrier function.
In plain English
This ingredient is a molecule made by attaching a silicon-containing group to the amino acid cystine. In cosmetics, it forms a thin, flexible film on hair or skin that helps lock in moisture and smooth the surface. For hair, it can improve strength and reduce breakage. For skin, it may help support the natural barrier without feeling heavy or greasy.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- semi synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Cystine Bis-PG-Propyl Silanetriol is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Cystine Bis-PG-Propyl Silanetriol.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
A semi-synthetic compound where cystine (an amino acid) is chemically bonded to a silanetriol group (a silicon-based molecule). This gives it both water-loving and film-forming properties.
How it works
When applied, the silicon part helps the ingredient spread evenly and form a protective film. The cystine part can bind to keratin in hair or skin, helping to reinforce the structure. This dual action makes it useful for strengthening hair fibers and temporarily smoothing the skin surface.
Pros
Strengthens hair fibers
The cystine component can bind to hair keratin, potentially reinforcing the hair shaft and reducing breakage from styling or brushing.
Lightweight film former
Unlike heavy silicones, this ingredient creates a thin, breathable film on hair or skin that doesn't feel sticky or greasy, making it suitable for fine hair.
Cons and cautions
Limited independent research
Most studies on this ingredient come from manufacturers, so independent peer-reviewed data on its long-term effects are scarce.
Variable performance
Its effectiveness depends heavily on the overall formulation and concentration; it may not deliver noticeable results in poorly formulated products.
Best for
- People with fine or damaged hair looking for strength without weight
- Those wanting a gentle film-forming ingredient for skin barrier support
Use caution if
- Individuals with known sensitivity to silicones or amino acid derivatives (rare)
Usage tips
Safety summary
Cystine Bis-PG-Propyl Silanetriol is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential. However, as with any ingredient, patch test if you have sensitive skin.
Research notes
Evidence is primarily from manufacturer studies and ingredient supplier data. It shows promise for hair strengthening and skin barrier support, but independent clinical trials are limited.
Common label clues
- Typical concentration
- 0.1% to 2%
- Regulatory status
- Approved for use in cosmetics in the EU, US, and other major markets. No specific restrictions beyond general cosmetic safety requirements.
- Common uses
- Hair serums, Leave-in conditioners, Anti-aging creams, Nail treatments
- Environmental note
- The silanetriol group is designed to be biodegradable, making it a potentially greener alternative to non-biodegradable silicones.
Good to know
- This ingredient is often used in 'bond repair' hair products alongside other amino acids.
- It is considered more eco-friendly than some traditional silicones because it is biodegradable.
Common questions
What is Cystine Bis-PG-Propyl Silanetriol in beauty products?
This ingredient is a molecule made by attaching a silicon-containing group to the amino acid cystine. In cosmetics, it forms a thin, flexible film on hair or skin that helps lock in moisture and smooth the surface. For hair, it can improve strength and reduce breakage. For skin, it may help support the natural barrier without feeling heavy or greasy.
What does Cystine Bis-PG-Propyl Silanetriol do in a beauty product?
When applied, the silicon part helps the ingredient spread evenly and form a protective film. The cystine part can bind to keratin in hair or skin, helping to reinforce the structure. This dual action makes it useful for strengthening hair fibers and temporarily smoothing the skin surface.
Is Cystine Bis-PG-Propyl Silanetriol safe for most people?
Cystine Bis-PG-Propyl Silanetriol is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential. However, as with any ingredient, patch test if you have sensitive skin.
Who should be careful with Cystine Bis-PG-Propyl Silanetriol?
Individuals with known sensitivity to silicones or amino acid derivatives (rare)
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.