Disodium Phosphate

Benefits
Tooth Whitening

What is Disodium Phosphate?

Disodium phosphate, chemically Na2HPO4, is an inorganic compound formed from phosphoric acid and sodium hydroxide. It exists as a white, crystalline powder highly soluble in water, making it ideal for aqueous cosmetic formulations. Commonly found in skincare cleansers, toners, shampoos, and toothpaste, it acts as a buffering agent to resist pH changes from ingredients or environmental factors, ensuring formulation stability. As a pH adjuster, it fine-tunes acidity levels to optimize preservative function and skin feel. It also inhibits corrosion on metal surfaces in packaging, preventing degradation, and can mask odors or support fragrance profiles, enhancing overall product quality and sensory appeal without altering texture.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1 View on EWG →
PubChem View on PubChem →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Buffering agent
Maintains the pH stability of a formulation.
Corrosion inhibitor
Reduces corrosion reactions on metal surfaces in packaging or applicators, helping prevent rust, off-odors, and metal-related discoloration over time.
Fragrance ingredient
Contributes scent character and/or masks base odors, shaping the overall sensory experience of the formula (subject to allergen and IFRA considerations).
PH adjuster
Raises or lowers pH to the target range, supporting ingredient performance, preservative efficacy, stability, and user comfort.
Anticorrosive
Protects metal components and packaging by reducing corrosion, helping maintain product integrity and preventing discoloration or contamination from metal surfaces.
Masking
Reduces perception of unpleasant odors or tastes by neutralizing them or covering them with more acceptable sensory notes.

Benefits

Maintains stable pH for better ingredient efficacy and skin comfort

Supports tooth whitening effects in oral care products

Protects packaging from corrosion to preserve product integrity

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Users of pH-sensitive skincare needing reliable stability
Those with rare sensitivity to phosphate salts
Individuals seeking effective oral care with whitening support
People preferring minimalist or phosphate-free routines
Consumers wanting long-lasting, odor-masked formulations
Individuals avoiding inorganic salts in topicals

Safety Notes

  • Recognized as low hazard in cosmetic safety assessments
  • Typically non-comedogenic with minimal irritation potential

Frequently Asked Questions about Disodium Phosphate

What role does disodium phosphate play in products?

It buffers pH, adjusts acidity, prevents corrosion, and masks odors for stable, effective formulas.

Is disodium phosphate safe for skin?

Yes, it's rated low hazard and safe as used in cosmetics with minimal irritation potential.

Does it help with tooth whitening?

In oral care, it supports whitening by aiding cleaning and stability in formulations.