Background: The aim of this in vivo study was to quantitatively assess the effects of two topical skincare products (Product A: massage oil; Product B: body lotion) on collagen-associated structural parameters of the epidermal basement membrane compared with untreated skin.
Methods: In an exploratory, controlled, and randomized pilot study, five female participants (aged 44-60 years; mean 51.4 ± 6.5) were enrolled. Five defined test sites on the volar forearms were examined. Participants applied the two test products according to the randomization scheme twice daily to two test sites over eight weeks, while three sites served as untreated control and baseline references. Suction blister biopsies were performed at baseline and after eight weeks. The blister roofs were subsequently analyzed by electron microscopy to assess collagen-associated structural parameters at the epidermal basement membrane.
Results: The microscopic evaluation indicated a consistent increase in collagen-associated structures in treated sites compared with the untreated control site after eight weeks. The products showed distinct response patterns: Product A induced more localized fiber compaction and bundling, whereas Product B resulted in a more homogeneous, area-wide increase in collagen distribution with reduced heterogeneity. Quantitative image analysis confirmed an overall increase in collagen-rich area fraction in treated sites relative to the untreated control. Product A showed a relative increase of 3%-20% (mean 13%), while Product B exhibited stronger effects of 12%-28% (mean 22%) compared to the control site. In the electron microscopic images, age related variations in collagen associated structural parameters were evident among the five participants. No relevant structural changes were observed in the untreated control site after eight weeks.
Conclusion: Both products led to measurable increases in collagen-associated structural parameters under controlled conditions. Product A and Product B induced different structural response patterns. Given the small sample size, these findings require confirmation in larger, statistically powered studies.

Background:
While the effects of conventional skincare formulations such as emulsions and creams are well documented, there is still limited scientific evidence regarding oil-based products such as massage oils, particularly with respect to their impact on the ultrastructural organisation of the skin barrier. At the same time, novel analytical methods now enable a combined assessment of lipid composition and lamellar organisation, although these have rarely been applied to such formulations to date.
Objective:
The aim of this study was to evaluate the effects of a plant oil-based massage oil on epidermal barrier function, hydration, as well as lipid composition and organisation within the stratum corneum, in comparison with untreated skin.
Methods:
In a randomised, controlled, intra-individual study, 12 healthy participants (mean age 47 years) were investigated. The skin barrier was deliberately disrupted by a 7-day pre-treatment with an SDS-containing cleansing product. Subsequently, a massage oil was applied twice daily for 2 days to one forearm, while the contralateral arm remained untreated. Hydration of the stratum corneum was measured using corneometry. Analyses were conducted using Lipbarvis® TEM (ultrastructural organisation) and Lipbarvis® LIP (lipid composition).
Results:
Treatment resulted in a significant increase in hydration (+29.1%, p<0.001), a marked increase in intercellular lipid lamellae (+116.6%, p<0.001), and a significant rise in total lipid content (+17.2%, p<0.001). The following increases were observed for individual lipids: cholesterol (+12%), free fatty acids (+27%), ceramide EOS (+17%), and ceramide AP (+15%). Conclusion: The results demonstrate that the tested plant oil-based formulation can effectively improve epidermal barrier function. The combined methodology enables, for the first time, a comprehensive ultrastructural characterisation of these effects.