Pentasodium Triphosphate (STPP): Properties, Uses, and Safety

Pentasodium triphosphate (sodium tripolyphosphate, STPP) is a white, water-soluble crystalline solid (Na₅P₃O₁₀).

Applications

• Cleaning Products: Dish soap, laundry/dishwasher detergent—softens water (sequesters Ca²⁺/Mg²⁺), suspends dirt.
• Water Softeners: Prevents scale in pipes/appliances.
• Industrial: Textile processing, leather tanning, papermaking.
• Food Additive: Emulsifier, stabilizer, thickener; tenderizes meat/fish. Generally recognized as safe (GRAS), but some may be allergic.

Read product labels; STPP is widely used and generally safe when used as directed.