Conclusion
The study revealed that LSM and TEWL
measurements represent appropriate methods
to investigate the penetration and the effect of
occlusion of various topically applied oils into
the stratum corneum. Paraffin oil, as well as the
vegetable oils, penetrated only into the first
upper layers of the stratum corneum. Thus, a
deeper penetration can be excluded. The
decreased TEWL values indicate that the application
of the oils leads to a semi-occlusion of
the skin surface as it is intended by the use of
oils to retain moisture in skin. Similar results
were obtained for mineral oil and the vegetable
oils. The highest decrease was found for petrolatum,
which is known on account of its
increased occlusion properties and was, therefore,
utilized as a positive control. While the
maximum effect in terms of occlusion of skin
by using raw oils in this study was shown, further
investigations to understand the penetration
of oils in combination with other cosmetic
ingredients need to be undertaken.