Sodium Citrate is the sodium salt of citric acid, a natural organic acid found abundantly in citrus fruits. In cosmetic chemistry, it is the industry standard for pH buffering and secondary chelation. Its ability to resist changes in pH when paired with Citric Acid makes it suitable for maintaining pH stability in aqueous challenging formulations.
Key Benefits and Performance
-
The “Gold Standard” Buffer: When used in a “Citrate Buffer” system (Sodium Citrate + Citric Acid), it allows formulators to lock a product into a specific, skin-friendly pH range (typically pH 4.5 – 5.5), preventing “pH drift” over time.
-
Secondary Chelation: Acts as a co-sequestering agent that binds metal ions like Calcium and Magnesium. This is particularly effective in rinse-off products (shampoos/body washes), where it prevents minerals in hard water from dulling hair or reducing foam volume.
-
Preservative Support: By stabilizing the pH, it ensures that pH-sensitive organic acid preservatives (such as Sodium Benzoate or Potassium Sorbate) remain in their active, undissociated state.
-
Formula Integrity: Prevents the discoloration and degradation of sensitive active ingredients that can be triggered by trace metal contamination.
