Trimethoxybenzylidene Pentanedione
INCI: 3-(3,4,5-Trimethoxybenzylidene)-2,4-pentanedione
A multi-functional sunscreen ingredient (commercial name Synoxyl HSS) that acts as a photostabilizer and SPF booster while providing antioxidant benefits.
Also known as: synoxyl hss
Benefits
- ✓Stabilizes sunscreen filters against UV degradation
- ✓Boosts SPF performance
- ✓Antioxidant protection
- ✓Chelates metal ions that could destabilize formulas
- ✓Eco-friendly and biodegradable
Watch for
- ⚠Relatively new ingredient with limited long-term safety data
In depth
What it does
A multi-functional sunscreen ingredient (commercial name Synoxyl HSS) that acts as a photostabilizer and SPF booster while providing antioxidant benefits. As an uv filter ingredient, it is particularly valued for stabilizes sunscreen filters against uv degradation, boosts spf performance, and antioxidant protection.
Skin type guide
Suitable for all skin types. Wearing SPF daily is one of the highest-impact habits in any skincare routine, regardless of skin type or concern.
How to use it
Apply as the final step of your AM routine, after moisturiser and before makeup. Most formulas require a generous, even layer — don't skimp. Reapply every 2 hours when outdoors.
