Ingredient review
Sodium Phenylbenzimidazole Sulfonate
INCI: SODIUM PHENYLBENZIMIDAZOLE SULFONATE
A safe, water-soluble UVB filter that feels lightweight and is less likely to clog pores, but offers no UVA protection on its own.
In plain English
Sodium Phenylbenzimidazole Sulfonate (also called Ensulizole) is a sunscreen ingredient that absorbs UVB rays—the type of sunlight that causes sunburn and contributes to skin cancer. Unlike many sunscreens that feel thick or greasy, this one is water-soluble, so it can be used in lightweight, clear formulas that don't leave a white cast. However, it does not protect against UVA rays (which cause aging and deeper skin damage), so it's almost always paired with other sunscreen ingredients for broad-spectrum protection.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is relatively strong for its common cosmetic role.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- synthetic
- Evidence
- strong
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Sodium Phenylbenzimidazole Sulfonate 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 Sodium Phenylbenzimidazole Sulfonate.
- 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
strongThere is a stronger practical or research basis for the ingredient role described here.
What it is
A synthetic, water-soluble organic compound that absorbs UVB radiation (280–320 nm) and converts it into harmless heat. It is approved as a sunscreen active ingredient by the FDA and other global regulators.
How it works
When applied to the skin, the molecule absorbs UVB photons and releases the energy as heat, preventing the UV radiation from penetrating deeper into the skin and causing sunburn or DNA damage. Because it is water-soluble, it can be formulated into lightweight, non-greasy products that feel comfortable on the skin.
Pros
Lightweight feel
Because it's water-soluble, sunscreens with this ingredient are often thin and non-greasy, making them comfortable for daily wear, especially under makeup.
No white cast
Unlike mineral sunscreens (zinc oxide, titanium dioxide), this ingredient doesn't leave a chalky residue, so it works well on all skin tones.
Cons and cautions
No UVA protection
This ingredient only blocks UVB rays. Without a UVA filter like avobenzone or zinc oxide, your skin is still vulnerable to aging and deeper damage from UVA light.
Potential photodegradation
Ensulizole can break down when exposed to sunlight, so it's often paired with photostabilizers or other filters to maintain effectiveness over time.
Best for
- People with oily or acne-prone skin who prefer lightweight sunscreens
- Those who dislike the white cast from mineral sunscreens
Use caution if
- Anyone relying on a single sunscreen ingredient for full protection—this must be used in a broad-spectrum formula
Usage tips
Safety summary
Sodium Phenylbenzimidazole Sulfonate is considered safe for use in sunscreens at approved concentrations by major regulatory bodies including the FDA and EU SCCS. It has a low irritation and allergy risk, though some individuals with very sensitive skin may experience mild reactions. It is not a known endocrine disruptor.
Research notes
Multiple studies confirm its efficacy as a UVB filter and its safety profile. Research also highlights its photodegradation tendency, which is managed through formulation. It is one of the most studied UV filters with a long history of safe use.
Common label clues
- Typical concentration
- Up to 4% in the US, up to 8% in the EU and other regions
- Regulatory status
- Approved by the FDA as a Category I sunscreen active ingredient in the US (up to 4%), and by the EU Cosmetics Regulation (up to 8%). Always check local regulations for exact limits.
- Common uses
- Sunscreens, Daily moisturizers with SPF, Makeup with SPF
- Environmental note
- Studies suggest it has low bioaccumulation potential and is less likely to harm marine life compared to some other organic UV filters, but more research is ongoing.
Good to know
- This ingredient is often listed as 'Phenylbenzimidazole Sulfonic Acid' on international labels, but the sodium salt form is used in water-based formulas.
- It is not a nanoparticle and does not raise the same environmental concerns as some other UV filters.
Common questions
What is Sodium Phenylbenzimidazole Sulfonate in beauty products?
Sodium Phenylbenzimidazole Sulfonate (also called Ensulizole) is a sunscreen ingredient that absorbs UVB rays—the type of sunlight that causes sunburn and contributes to skin cancer. Unlike many sunscreens that feel thick or greasy, this one is water-soluble, so it can be used in lightweight, clear formulas that don't leave a white cast. However, it does not protect against UVA rays (which cause aging and deeper skin damage), so it's almost always paired with other sunscreen ingredients for broad-spectrum protection.
What does Sodium Phenylbenzimidazole Sulfonate do in a beauty product?
When applied to the skin, the molecule absorbs UVB photons and releases the energy as heat, preventing the UV radiation from penetrating deeper into the skin and causing sunburn or DNA damage. Because it is water-soluble, it can be formulated into lightweight, non-greasy products that feel comfortable on the skin.
Is Sodium Phenylbenzimidazole Sulfonate safe for most people?
Sodium Phenylbenzimidazole Sulfonate is considered safe for use in sunscreens at approved concentrations by major regulatory bodies including the FDA and EU SCCS. It has a low irritation and allergy risk, though some individuals with very sensitive skin may experience mild reactions. It is not a known endocrine disruptor.
Who should be careful with Sodium Phenylbenzimidazole Sulfonate?
Anyone relying on a single sunscreen ingredient for full protection—this must be used in a broad-spectrum formula
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.