The aim of the present study is to use neutron diffraction enhanced with isotopic substitution and subsequent computer simulations to determine the head group solvation of a very short dichain chain phosphatidylcholine molecule in a 30 mol% mixture of 1,2 propandiol and water in order to understand why the presence of 1,2 propandiol in a formulation leads to greater drug penetration into the skin. It is of particular interest in the present study to determine whether the 1,2 propandiol preferentially solvates the lipid head group as has been suggested by some researchers. A mixture of 30% of 1,2 propandiol in water was selected for this study as it has been shown that this system leads to an enhanced skin penetration of a range of poorly-water soluble drugs.