The increase in skin hydration after application of emollients with different amounts of lipids.

Emollients can increase the water content in the stratum corneum by delivery of their water to the skin, and by occlusion. These two mechanisms were studied using three preparations with different concentrations of lipids. The products were applied to the skin and then removed by cleaning the surface after 5 and 40 min. The increase in skin water loss following removal of product residue was considered as a release of excess water in the skin. Exposure of the skin to pure petrolatum for 5 min gave no increase in the water loss from the skin surface following removal of the product residue. A lipid rich cream (66% lipids) gave a significant increase, but the highest increase was found after removal of an ordinary cream (27% lipids). Release of water from the skin indicates that water in the creams had previously been absorbed into the skin. The occluding properties of the products were determined after 40 min of exposure. Petrolatum reduced the water loss by approximately 50% and the other products by 16%. The occlusion caused an increase of water in the skin, which resulted in a release of water following removal of the products. The release was related to the reduction of water loss. Thus petrolatum gave a higher release of water than the other emollients.