What Is Benzophenone-4?
Benzophenone-4 is the cosmetic name for 5-benzoyl-4-hydroxy-2-methoxybenzenesulfonic acid, a small organic molecule designed to absorb specific wavelengths of ultraviolet (UV) light. It is synthesized in a lab by joining a benzophenone backbone with sulfonic acid and methoxy groups, a process that boosts water solubility and UV filtering power. First explored in the 1970s as chemists searched for more photo-stable sunscreen agents, it quickly found a place in personal care formulas because it resists breaking down when exposed to sunlight.
Today manufacturers include Benzophenone-4 in a wide range of water-based cosmetics. You are most likely to see it in facial and body sunscreens, daily moisturizers with SPF, color-protecting hair products, nail lacquers, lip balms with sun protection, leave-in conditioners, light-weight serums and some facial masks that need extra stability under daylight or store lighting.
Benzophenone-4’s Cosmetic Benefits/Uses
Formulators turn to Benzophenone-4 whenever a product needs reliable protection against UV damage or color fade.
- Light Stabilizer: Helps keep the overall formula from degrading when exposed to sunlight so the texture, scent and active ingredients stay effective for longer
- UV Absorber: Captures and dissipates UV energy before it can reach skin or the product itself which reduces the risk of sun-induced irritation and prevents color changes in dyed or tinted items
- UV Filter: Contributes to the SPF value in sunscreens and SPF-labeled moisturizers by filtering out both UVA and UVB rays, offering a broader shield than many single-action filters
Who Can Use Benzophenone-4
Benzophenone-4 is generally suitable for all skin types including normal, oily, dry and sensitive skin because it is water soluble and used at low levels. People with very reactive or eczema-prone skin should still read labels carefully since any UV filter can be a trigger in rare cases.
The ingredient is synthetic and contains no animal derived components so it is considered friendly for both vegans and vegetarians.
Current safety reviews show no evidence that topical Benzophenone-4 is harmful during pregnancy or while breastfeeding. That said, this is not medical advice and anyone who is pregnant or nursing should check with a doctor before adding new skincare products to a routine just to be safe.
Benzophenone-4 itself does not cause photosensitivity. Its whole purpose is to absorb UV light so it can actually help reduce light related irritation when blended into sunscreen or color-protective formulas.
Potential Side Effects/Adverse Reactions
Reactions to Benzophenone-4 can vary from person to person. The points below list potential side effects yet most users will not notice any issues when the ingredient is used at the low amounts allowed in cosmetics.
- Skin stinging or mild burning
- Redness or itchiness on very sensitive skin
- Rare allergic contact dermatitis
- Eye irritation if a product migrates into the eyes
- Increased dryness when paired with strong alcohol-based formulas
If any of these reactions occur stop using the product and consult a healthcare professional or pharmacist for guidance.
Comedogenic Rating
Rating: 0 / 5
Benzophenone-4 is completely water-soluble so it does not leave an oily film that could block pores. It is typically used at very low concentrations and has no occlusive or waxy characteristics, meaning it sits lightly on the skin then rinses away without residue. For these reasons it earns a 0 rating.
This makes the ingredient suitable for people who are prone to acne or frequent breakouts.
The only caveat is that some sunscreens containing Benzophenone-4 may also include richer emollients or silicones which can influence how pore-friendly the finished product feels, so always consider the full ingredient list rather than judging by one component alone.
Summary
Benzophenone-4 works as a light stabilizer, UV absorber and UV filter by soaking up incoming UVA and UVB rays then converting that energy into less harmful forms before it can strike the skin or degrade other ingredients. This keeps formulas stable, colors true and SPF claims reliable.
While not the most talked-about sunscreen agent, it quietly appears in many water-based sunscreens, daily moisturizers with SPF, hair products and nail lacquers that need extra photo protection, making it a steady if low-key player in the cosmetic world.
Regulatory reviews in the EU, United States and other regions agree it is safe at the levels allowed in cosmetics, with only rare reports of irritation. As with any new skincare product, patch testing on a small area is wise to make sure your skin likes the overall formula.