Hair Serum Formulation: Water and Oil Phases

Regarding your hair serum formula containing both water and oil phases without an explicitly listed emulsifier, it's understandable to be concerned about separation.

However, some ingredients commonly used as conditioning agents in hair products, such as Behentrimonium Chloride (BTAC) or Behentrimonium Methosulfate (BTMS), also possess emulsifying properties. This means they can help blend the water and oil phases together to create a stable mixture.

As mentioned in the staff reply, Behentrimonium Chloride (BTAC) acts as an emulsifier and can help combine water and oil. A general guideline is that 3% BTAC is often sufficient for formulas containing around 5% oil. If your formula has a higher percentage of oil, you might need to experiment with the concentration of the conditioning agent or emulsifier to ensure stability and prevent separation.

Behentrimonium Methosulfate (BTMS) is another common conditioning agent (available as BTMS 90% or BTMS 50%) that also functions as an emulsifier, widely used in conditioners and treatments to provide softness to hair.

Recommendation:

Check your formula to see if it includes ingredients like Behentrimonium Chloride, Behentrimonium Methosulfate, or other similar cationic conditioning agents. If one of these is present, it is likely serving as the emulsifier for your water and oil phases.

If your formula does not contain such an ingredient, you would need to add a suitable emulsifier or a conditioning agent with emulsifying properties (like BTAC or BTMS) to ensure the water and oil remain mixed and the serum is stable.

Always perform a small test batch first to check for stability and make sure the product does not separate before making a larger quantity.