Synopsis This review was initially prepared in 2011 before Professor Johann Wiechers tragically passed away. It has been updated and is being published in his memory. It discusses the importance of mineral oil and its benefits to skin. Its source, structure, properties and efficacy are discussed. Mineral oil has been shown to improve skin softness and barrier function better than some other emollients using the gas‐bearing dynamometer and standard water vapour transmission testing as well as in vivo studies showing its effects on suppressing transepidermal water loss (TEWL). It has also been subjected to the rigour of the newer in vivo confocal microscopic measurements now used for testing the performance of moisturizers by following the swelling characteristics of the stratum corneum and been found favourable compared with many vegetable oils. Its introduction as a cosmetic oil was in the late 1800s, and still today, it is used as one of the main components of moisturizers, a true testament to its cost to efficacy window. Naturally, it has physical effects on the stratum corneum, but it is expected that these will translate into biological effects simply through its mechanism of hydrating and occluding the stratum corneum from which many benefits are derived.

SynopsisScars are well known to have a stratum corneum (SC) that is malfunctional. Increases in transepidermal water loss and decreases in SC capacitance and conductance have been reported. Occlusion therapy is a well-known route to improving the signs and symptoms of scarring. Until recently that has been assumed to be totally pressure related. However, studies have demonstrated that the direct effects of hydration on keratinocytes and fibroblasts contribute to the reduction in hypertrophic scarring. Now it is well known that occlusion can regulate epidermal cytokine and growth factor production; changes in profibrotic and anti-fibrotic factors have been established. As a result, it is to be expected that moisturizers may improve the signs and symptoms of scars. As striae have been suggested to be anatomically similar to scars and as it is well established that paracrine signalling occurs in skin, it is expected that striae have similar SC issues. While one cannot exclude the effects of some of the ingredients used in the products, several studies are reported in this review that demonstrates that moisturization is a key component to reducing the clinical signs and symptoms of scars and striae. This is a good example of how knowledge of corneobiology leads to corneotherapies for these skin condition problems. The review is being written in memory of Professor Johann Wiechers who, before he died tragically in November 2011, performed two of the reported studies together with colleagues. Ré suméLes cicatrices sont bien connues pour avoir une couche cornée dysfonctionnelle. L'augmentation de la perte insensible en eau et une diminution de la capacité de la couche cornée et de la conductance ont été signalées. La thérapie d'occlusion est une voie bien connue pour l'amélioration des signes et symptômes de la cicatrisation. Jusqu'à une date récente cela a été supposé être totalement lié à la pression. Cependant, des études ont démontré que les effets directs de l'hydratation sur les kératinocytes et des fibroblastes contribuent à la réduction de cicatrices hypertrophiques. Maintenant, il est bien connu que occlusion peut réguler la production de cytokines épidermiques et du facteur de croissance; des changements dans les facteurs profibrotiques et antifibrotiques ont été éta-blis. En conséquence, il faut s'attendre à ce que les hydratants peuvent améliorer les signes et symptômes des cicatrices. Puisque les striae sont considérés être anatomiquement semblables à des cicatrices, et depuis qu'il est bien établi que la signalisation paracrine se produit dans la peau, on peut s'attendre à ce que les striae présentent des caractéristiques similaires au niveau de la couche cornée. Bien que l'on ne puisse pas exclure les effets de quelquesuns des ingrédients utilisés dans les produits, plusieurs études sont rapportés dans cette revue qui démontre que l'hydratation est une composante clé de la réduction des signes et des symptômes cliniques des cicatrices et vergetures. C'est un bon exemple de la façon dont la connaissance d...

Collectively, these results show the cumulative improvements in the signs of photoaging compared to a no-treatment control group for the oil-based antiaging moisturizer for the first time. The differences in the efficacy of the vitamin A palmiate and antioxidant oil-based moisturizer on different body sites probably reflect the differences in likely photodamage.

Scars are well known to have a stratum corneum that is malfunctional. Increases in transepidermal water loss and decreases in stratum corneum capacitance and conductance have been reported. Occlusion therapy is a well-known route to improving the signs and symptoms of scarring. Until recently that has been assumed to be totally pressure related. However, studies have demonstrated that the direct effects of hydration on keratinocytes and fibroblasts contribute to the reduction in hypertrophic scarring. Now it is well known that occlusion can regulate epidermal cytokine and growth factor production; changes in profibrotic and antifibrotic factors have been established. As a result it is to be expected that moisturisers may improve the signs and symptoms of scars. As striae have been suggested to be anatomically similar to scars and since it is well established that paracrine signalling occurs in skin it is expected that striae have similar stratum corneum issues. While one cannot exclude the effects of some of the ingredients used in the products, several studies are reported in this review which demonstrates that moisturisation is a key component to reducing the clinical signs and symptoms of scars and striae. This is a good example of how knowledge of corneobiology leads to corneotherapies for these skin condition problems. The paper is being written in memory of Professor Johann Wiechers who, before he died tragically in November 2011, performed two of the reported studies together with colleagues. © 2012 Society of Cosmetic Scientists and the Société Française de Cosmétologie.