A randomized clinical trial evaluated the effects of extra virgin olive oil and petrolatum on skin barrier function and microtopography. Both treatments improved short-term skin hydration and barrier parameters in healthy adults, although via different mechanisms.

The trial included 54 participants (mean age, 28.6 years; 50% female). Each individual received applications of 0.2 mL of either cold-pressed extra virgin olive oil (EVOO) or white petrolatum to demarcated 9-cm² areas of the inner forearm. A third adjacent area remained untreated as a control. After a 60-minute exposure, investigators performed biophysical measurements, including assessments of hydration, transepidermal water loss (TEWL), temperature, erythema, and skin surface characteristics.

Barrier Function Outcomes

Stratum corneum hydration (SCH) increased significantly in both treatment areas. SCH rose from 40.23 arbitrary units (AU) at baseline to 48.66 AU with EVOO and 49.15 AU with petrolatum (both P < .001). Erythema and skin temperature also decreased significantly with both treatments, suggesting an immediate soothing effect.

Only petrolatum significantly reduced TEWL, from 9.56 g/m²/h to 8.18 g/m²/h (P = .01). EVOO resulted in a non–statistically significant decrease in TEWL to 8.52 g/m²/h (P = .06). These findings are consistent with the occlusive properties of petrolatum, which may better preserve water retention.

Corneocyte Composition and Skin Surface Texture

Both EVOO and petrolatum influenced skin microtopography and corneocyte composition. EVOO significantly increased the proportion of early-stage (type 1) corneocytes, from 6.02 mm² in untreated areas to 7.11 mm² (P = .01), and to a greater extent than petrolatum (5.87 mm²; P < .001). Petrolatum was more effective at reducing mature corneocyte types (types 2–5) and at lowering the desquamation index, from 20.03 AU to 10.03 AU (P < .001), compared with 14.13 AU for EVOO-treated skin (P < .001).

These findings suggest that petrolatum primarily reinforces the outer skin barrier and reduces cellular shedding, whereas EVOO may promote epidermal regeneration and turnover.

Tolerability and Subjective Evaluation

Both products were well tolerated. Participants rated EVOO higher than petrolatum in skin color appearance (8.14 vs 7.05, P = .02). Other domains, including absorption, texture, and irritation, did not differ significantly.

Conclusion

Both EVOO and petrolatum improved skin barrier function and surface characteristics after a single topical application. Petrolatum produced a greater reduction in TEWL and desquamation, whereas EVOO promoted a higher proportion of early-stage corneocytes, indicating a potential role in supporting skin renewal. As the evaluation occurred only at a single time point, further studies are warranted to assess long-term and cumulative effects.

Full disclosures can be found in the published study.

Source: Journal of Clinical Medicine