HLB (Hydrophilic-Lipophilic Balance) – Cosmetic Uses in Emulsion Formulation

What Is HLB?

HLB stands for Hydrophilic-Lipophilic Balance. It is a numerical system used to describe the relative affinity of a surfactant for water and oil.

The HLB value helps formulators select emulsifiers according to the type of emulsion they want to create. More hydrophilic surfactants generally have higher HLB values, while more lipophilic surfactants have lower values.

HLB in Cosmetic Emulsions

HLB is particularly useful when formulating oil-in-water (O/W) and water-in-oil (W/O) emulsions.

• Higher HLB values are generally associated with more hydrophilic emulsifiers and O/W emulsions.
• Lower HLB values are generally associated with more lipophilic emulsifiers and W/O emulsions.

The HLB system can also be used to calculate or estimate the required emulsifier balance for a particular oil phase.

HLB and Emulsifier Selection

The required HLB of the oil phase depends on the oils and other lipophilic materials present in the formulation. When several oils are used, their individual required HLB values can be considered together to determine a suitable target.

A combination of two or more emulsifiers can then be selected to achieve the desired overall HLB.

However, HLB should be treated as a formulation guideline rather than a complete prediction of emulsion stability. Emulsifier chemistry, concentration, oil phase composition, processing conditions, droplet size, viscosity and other formulation components can all influence the final emulsion.

HLB in Cosmetic Formulation

The HLB system is commonly applied when developing:

• Face and body creams
• Lotions
• Sunscreens
• Cleansing emulsions
• Hair conditioners
• Other O/W and W/O cosmetic emulsions

Experimental formulation and stability testing remain essential, even when the theoretical HLB has been calculated.

Source: Cosmetic Formulation Principles and Practice - Heather A.E. Benson, Michael S. Roberts, Vânia Rodrigues Leite-Silva, Kenneth A. Walters.