4-Methylbenzylidene Camphor

4-Methylbenzylidene camphor (4-MBC) is a synthetic organic UV filter commonly used in sunscreens and sun-protective skincare products. It works by absorbing ultraviolet radiation and converting it into heat, thereby preventing UV rays from penetrating the skin. The ingredient is found in roughly 0.1% of skincare formulations globally.

As a chemical filter, 4-MBC differs from mineral (physical) sunscreens in its mechanism—it sits on and slightly into the skin rather than sitting on the surface. It is typically used at concentrations between 2% and 4% in finished products.

4-MBC functions as a chemical absorber by accepting energy from UV photons and dissipating it as heat through molecular excitation. This process prevents UV radiation from reaching deeper layers of the skin where it can cause DNA damage, inflammation, and premature ageing.

The ingredient absorbs across both UVB (280–320 nm) and UVA wavelengths, though it is particularly effective in the UVB range. Application to clean, dry skin allows it to disperse and form a protective layer.

Apply 4-MBC-containing sunscreens generously to all exposed skin 15 minutes before sun exposure, and reapply every two hours or immediately after swimming or sweating. Use as part of a comprehensive sun-protection strategy that includes seeking shade during peak UV hours (10am–4pm) and wearing protective clothing. Ensure even distribution for optimal coverage and effectiveness.