Excerpt from a scientific study:
Effects of extra virgin olive oil and petrolatum on skin barrier function and skin microtopography.
Summary
Context/Objectives: Natural oils are widely promoted and used around the world as part of skincare. Among them, extra virgin olive oil (extra virgin olive oilEVOO stands out for its wide range of organic compounds and its well-known moisturizing properties. This study aimed to evaluate the effects of topical application of EVOO compared to petrolatum on skin barrier function (skin barrier function, SBF) and skin microtopography.
Methods: A randomized, intra-individual clinical trial was conducted with healthy adult volunteers. EVOO and petrolatum were applied to defined areas on the volar forearm. Parameters related to SBF were evaluated, including stratum corneum hydration (stratum corneum hydration, SCH), transepidermal water loss (transepidermal water loss, TEWL), temperature and erythema. Skin microtopography was assessed by two approaches: (1) topographic parameters — surface roughness, scaling, smoothness and wrinkles; and (2) stratum corneum composition (stratum corneum, SC) — corneocyte subtypes and desquamation index (desquamation index, DI). Participants also answered a tolerability questionnaire for each product.
Results: A total of 54 participants (50% female; mean age: 28,57 ± 11,02 years) completed the study. Both EVOO and petrolatum significantly improved SBF, increasing stratum corneum hydration and reducing erythema and skin temperature. Petrolatum also reduced TEWL. Regarding skin microtopography, both products decreased the desquamation index and reduced the prevalence of mature corneocytes (types 2–5). These effects were more pronounced with petrolatum. Notably, EVOO significantly increased the proportion of early-stage corneocytes (type 1).
Conclusions: Both EVOO and petrolatum effectively improved skin barrier function and microtopographic characteristics. While petrolatum exerted a stronger occlusive effect, reducing TEWL and desquamation, EVOO uniquely promoted epidermal renewal by increasing epidermal turnover.
Introduction
Vegetable oils have long been used in dermatology and cosmetology due to their wide range of physiological benefits for the skin [1]. Topical application of vegetable oils can provide a protective barrier by exerting an occlusive effect, thus increasing skin hydration by reducing transepidermal water loss (TEWL) [2]. Unlike systemic treatments, topical formulations offer the advantages of greater local bioavailability and lower systemic exposure, making them ideal for targeted cutaneous therapies [1,2].
Several plant-derived oils have been studied for their ability to promote skin health [3]. In particular, olive oil (olive oil, OO) is rich in monounsaturated fatty acids (especially oleic acid) and contains a complex profile of bioactive compounds, such as polyphenols, including phenolic alcohols, phenolic acids, flavonoids, lignans and secoiridoids [4]. These phenolic compounds have strong antioxidant, anti-inflammatory and skin-regenerating properties, and may contribute to strengthening the skin barrier function and reducing skin inflammation [4,5].
Extra virgin olive oil (EVOO), obtained by cold pressing, maintains a higher concentration of these bioactive molecules compared to refined oils, due to the absence of heat or chemical processing [5]. EVOO may offer superior benefits in maintaining and restoring the integrity of the skin barrier [4,6,7].
In clinical practice, especially in primary care [8], EVOO is commonly used in procedures such as softening earwax before its removal, managing chronic wounds and preventing xerosis in geriatric patients [8,9]. Due to its anti-inflammatory properties, it is also occasionally used in conditions such as eczema, rosacea and psoriasis [9].
Similarly, petrolatum is widely used in skin disorders, including postoperative wounds [10], irritant contact dermatitis [11] and chronic hand eczema [12]. The use of both substances is often driven by their accessibility and low cost, especially in resource-limited settings [9,10]. However, despite their widespread traditional use and favorable compositions, there is still limited robust scientific evidence to support their effects on the biophysical parameters of skin barrier function.
Therefore, the aim of this study was to investigate the effects of topical application of EVOO and petrolatum on skin barrier function and microtopography in healthy adult volunteers. By evaluating key indicators such as TEWL, hydration, and surface texture, this research seeks to elucidate the dermatological potential of EVOO and support its evidence-based use in skin care and therapy.
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