Ethylhexyl Triazone

Ethylhexyl Triazone is an oil-soluble UVB filter typically used around ~1–5% in sunscreens, and it is considered photostable with low skin penetration, which correlates with low irritancy in routine use. Human repeat-insult patch testing and post-market data generally show a low rate of irritation/sensitization, with reactions more often attributable to the overall sunscreen vehicle rather than this filter itself. For highly reactive or eczema-prone skin I still treat it as a low-but-not-zero risk ingredient due to cumulative exposure and formulation factors, so it rates as very gentle rather than inert. Safety Notes: In real-world OTC sunscreens (leave-on), Ethylhexyl Triazone is often used at low levels (~0.1–1%) as a UVB booster to help reach high SPF while improving photostability and reducing reliance on other UVB filters. High-protection European/Asian SPF50+ products commonly use ~2–5%, and 5% represents the EU maximum allowed concentration for this UV filter in leave-on cosmetics; rinse-off products rarely use it and typically stay at trace/low levels when present.