Ingredient review
Methoxycinnamoylpropyl Silsesquioxane Silicate
INCI: METHOXYCINNAMOYLPROPYL SILSESQUIOXANE SILICATE
A silicone-bound UV filter that offers broad-spectrum protection with a lightweight, non-greasy feel.
In plain English
This ingredient is a UV-absorbing molecule attached to a silicone backbone. It helps protect your skin from the sun while making the product feel silky and smooth, not sticky or heavy. Because it's silicone-based, it spreads easily and can help other ingredients stay on your skin longer.
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
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Methoxycinnamoylpropyl Silsesquioxane Silicate 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 Methoxycinnamoylpropyl Silsesquioxane Silicate.
- 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 synthetic hybrid molecule that combines a UV-absorbing cinnamate group with a silicone polymer (silsesquioxane). It is designed to be photostable and water-resistant.
How it works
The cinnamate portion absorbs UVB and some UVA rays, converting them into harmless heat. The silicone backbone helps the ingredient form an even, flexible film on the skin, improving spreadability and water resistance.
Pros
Lightweight feel
The silicone base gives sunscreens a silky, non-sticky texture that many people find more comfortable than traditional sunscreen lotions.
Good photostability
Unlike some standalone cinnamates, this silicone-bound version is more stable under sunlight, so it doesn't break down as quickly.
Cons and cautions
Moderate UVA protection
This ingredient primarily absorbs UVB rays. For broad-spectrum protection, it must be combined with other UVA filters.
Synthetic origin
It is a lab-made silicone hybrid, which may not align with preferences for natural or biodegradable ingredients.
Best for
- Anyone looking for a lightweight, non-greasy sunscreen
- People with oily or combination skin
Use caution if
- Those seeking very high UVA protection
- Individuals who prefer mineral-only sunscreens
Usage tips
Safety summary
Considered safe for topical use at typical concentrations. Low irritation and allergy risk. Not known to be a significant environmental concern, but silicone persistence is a consideration for eco-conscious consumers.
Research notes
Limited peer-reviewed studies specifically on this hybrid molecule, but its components (cinnamate UV filters and silicones) are well-studied. Photostability is a key advantage over traditional octinoxate.
Common label clues
- Typical concentration
- 1–10% in sunscreen formulations
- Regulatory status
- Approved as a UV filter in many countries including the US (OTC monograph) and EU (Annex VI). Always check local regulations as concentrations may be limited.
- Common uses
- Sunscreens, Moisturizers with SPF, Primers, BB creams
- Environmental note
- Silicone-based ingredients can be persistent in the environment. Some reef-safe sunscreen guidelines recommend avoiding certain silicone compounds, though this specific ingredient is not commonly flagged.
Good to know
- This ingredient is often listed alongside other UV filters to achieve broad-spectrum protection.
- It is not a nanoparticle and does not leave a white cast.
Common questions
What is Methoxycinnamoylpropyl Silsesquioxane Silicate in beauty products?
This ingredient is a UV-absorbing molecule attached to a silicone backbone. It helps protect your skin from the sun while making the product feel silky and smooth, not sticky or heavy. Because it's silicone-based, it spreads easily and can help other ingredients stay on your skin longer.
What does Methoxycinnamoylpropyl Silsesquioxane Silicate do in a beauty product?
The cinnamate portion absorbs UVB and some UVA rays, converting them into harmless heat. The silicone backbone helps the ingredient form an even, flexible film on the skin, improving spreadability and water resistance.
Is Methoxycinnamoylpropyl Silsesquioxane Silicate safe for most people?
Considered safe for topical use at typical concentrations. Low irritation and allergy risk. Not known to be a significant environmental concern, but silicone persistence is a consideration for eco-conscious consumers.
Who should be careful with Methoxycinnamoylpropyl Silsesquioxane Silicate?
Those seeking very high UVA protection Individuals who prefer mineral-only sunscreens
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.