Ingredient review
Potassium Methoxycinnamate
INCI: Potassium Methoxycinnamate
A synthetic UVB filter that helps shield skin from sunburn, but its use is limited in some regions due to regulatory differences.
In plain English
Potassium Methoxycinnamate is a man-made ingredient that absorbs ultraviolet B (UVB) rays from the sun, preventing them from penetrating the skin and causing sunburn. It works like a tiny sponge that soaks up UV energy and converts it into harmless heat. You'll find it in sunscreens and some daily SPF products, but it's not as common in the U.S. as it is in Asia and Europe.
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
Potassium Methoxycinnamate 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 Potassium Methoxycinnamate.
- 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 organic compound derived from cinnamic acid, designed to absorb UVB radiation (280–320 nm). It is a salt form of methoxycinnamate, making it water-soluble and easier to formulate into clear or lightweight products.
How it works
When applied to the skin, the molecule absorbs UVB photons and releases the energy as low-level heat, preventing the UV rays from damaging skin cells. It is often combined with other UV filters to provide broad-spectrum protection.
Pros
Effective UVB filter
Absorbs UVB rays efficiently, helping to prevent sunburn and reduce the risk of skin damage.
Lightweight feel
Because it is water-soluble, it can be formulated into non-greasy, clear lotions and gels that feel comfortable on the skin.
Cons and cautions
Limited UVA protection
On its own, it does not protect against UVA rays, which cause premature aging and deeper skin damage. It must be paired with other filters.
Not globally approved
It is not approved as a sunscreen ingredient by the U.S. FDA or Australian TGA, so products containing it may not be available in those markets.
Best for
- People looking for lightweight, water-resistant sun protection
- Those who prefer water-soluble UV filters in daily SPF products
Use caution if
- Individuals with extremely sensitive or reactive skin (patch test recommended)
- Those seeking a sunscreen approved by the U.S. FDA
Usage tips
Safety summary
Generally considered safe for topical use in approved concentrations. Mild irritation is possible in sensitive individuals. Its safety profile is well-studied in regions where it is approved, but it is not authorized in the U.S. or Australia.
Research notes
Studies confirm its effectiveness as a UVB absorber. Research on long-term systemic absorption is limited, but current evidence supports its safety at typical use levels. More data is needed on environmental impact.
Common label clues
- Typical concentration
- Up to 10% in rinse-off products; up to 5% in leave-on products (varies by region)
- Regulatory status
- Approved as a UV filter in the EU and many Asian countries (e.g., Japan, Korea) at concentrations up to 10%. Not approved by the U.S. FDA or Australian TGA for use in sunscreens.
- Common uses
- Sunscreens, Daily moisturizers with SPF, BB creams
- Environmental note
- Some cinnamate-based UV filters have raised concerns about coral reef toxicity, but specific data on Potassium Methoxycinnamate is limited. Reef-safe alternatives are recommended for ocean exposure.
Good to know
- Potassium Methoxycinnamate is sometimes listed as 'Potassium p-Methoxycinnamate' on ingredient labels.
- It is more commonly found in Asian and European sunscreens than in U.S. products.
Common questions
What is Potassium Methoxycinnamate in beauty products?
Potassium Methoxycinnamate is a man-made ingredient that absorbs ultraviolet B (UVB) rays from the sun, preventing them from penetrating the skin and causing sunburn. It works like a tiny sponge that soaks up UV energy and converts it into harmless heat. You'll find it in sunscreens and some daily SPF products, but it's not as common in the U.S. as it is in Asia and Europe.
What does Potassium Methoxycinnamate do in a beauty product?
When applied to the skin, the molecule absorbs UVB photons and releases the energy as low-level heat, preventing the UV rays from damaging skin cells. It is often combined with other UV filters to provide broad-spectrum protection.
Is Potassium Methoxycinnamate safe for most people?
Generally considered safe for topical use in approved concentrations. Mild irritation is possible in sensitive individuals. Its safety profile is well-studied in regions where it is approved, but it is not authorized in the U.S. or Australia.
Who should be careful with Potassium Methoxycinnamate?
Individuals with extremely sensitive or reactive skin (patch test recommended) Those seeking a sunscreen approved by the U.S. FDA
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.