What it is
Tetrahydroxypropyl ethylenediamine is a small synthetic molecule that helps buffer and stabilize the pH of a formulation and can bind metal ions that would otherwise degrade other ingredients. In sun care products such as sticks and emulsions it is used at low levels to keep the system stable. It is a functional aid rather than an active skincare ingredient.
Safety & warnings
Used at low levels and generally considered well tolerated in rinse-off and leave-on products. As an alkaline amino alcohol it is buffered within the finished formula, so the product as a whole sits at a skin-appropriate pH. Not associated with comedogenicity.
Origin & sourcing
Synthetic; manufactured by reacting ethylenediamine with propylene oxide.
Questions everyone asks
Why is tetrahydroxypropyl ethylenediamine added to sunscreen?
It helps adjust and stabilize the product's pH and can chelate trace metals, supporting overall formula stability.
Is it an active ingredient?
No. It is a formulation aid that supports stability and pH, not a UV filter or treatment ingredient.