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Sodium Phosphate

INCI: SODIUM PHOSPHATE

Reviewed by Emma · Last updated 14 Aug 2026

A buffering agent that helps maintain the pH balance of skincare formulations

Best For Skin Types

All

Usage Frequency

As part of formulated product

What Is Sodium Phosphate?

Sodium phosphate is a salt derived from phosphoric acid. In skincare formulations, it serves as a buffering agent—a component that helps stabilise and maintain the pH of a product, preventing it from becoming too acidic or alkaline over time.

As a buffering ingredient, sodium phosphate works behind the scenes rather than directly on the skin. It is present in only a small percentage of skincare products, typically where pH stability is important for formula efficacy or safety.

How It Works

Sodium phosphate works through its buffering capacity. When added to a formulation, it can neutralise excess acid or base, keeping the pH within a narrow, stable range. This is important because many skincare actives—such as vitamin C or certain exfoliating acids—require a specific pH to remain stable and effective on skin.

Clinical Evidence & References

Sodium phosphate is well established as a pharmaceutical and cosmetic buffering agent, with a long history of safe use in formulations. However, there is limited direct research on its specific effects when applied topically in skincare products. Its role is primarily functional—maintaining formula integrity rather than providing direct therapeutic benefit to skin.

How to Use

As a buffering agent, sodium phosphate concentration and effectiveness are optimised during product formulation. There are no specific usage guidelines for consumers; simply use the product as directed by the manufacturer.

Safety & Precautions

Sodium phosphate is generally well-tolerated and recognised as safe in cosmetic formulations at typical use levels. No significant irritation concerns have been documented for topical skincare use.

Frequently Asked Questions

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