The invention includes a method of increasing the substantivity of a personal care composition to hair, skin or nails by preparing a composition of an aqueous phase, a non-aqueous phase and a neutralized amino acid ester that is a reaction product of a neutral amino acid having a non-polar side chain with a long chain fatty alcohol and is represented by formula (I): wherein R 1 is an alkyl group；R 2 is a linear or branched carbon chain； and the amine group of the amino acid is neutralized with an acid. The composition is substantially free of petrochemicals and/or derivatives of petrochemical materials. The aqueous phase and the non-aqueous phase are emulsified by the neutralized amino acid ester. Other methods and an emulsifiers that is the neutralized amino acid ester are included. Because the neutralized amino acid ester and the compositions do not contain petrochemical-derived ingredient, the products are natural.
