Objective: To elucidate the effects of sea salt and various other soap ingredients on skin in humans.
Methods: Forty healthy women (age 30.4 ± 6.0 years) were assigned to one of four test-soap groups (sea salt, SS; collagen added, SS+C; humic added, SS+H; or, fucoidan added, SS+F) or a control group. Subjects washed their face with the soap twice daily for eight weeks. Before and after the study, subjects undertook the Anti-Aging QOL Common Questionnaire (AAQol), skin image analysis (VISIAII), elasticity tests by a Cutometer (MPA580), and moisture tests by a Corneometer (CM825).
Results: At 8 weeks, significant improvements were seen in symptoms scores for “noticeable blackheads in pores” and “oily face” in the SS group, the score for “concerned about spots or freckles” in the SS+H group, and the scores for “noticeable pores”, “concerned about pore opening”, “dry skin”, “rough skin”, “concerned about rough skin”, and “corner of eyes sagging” in the SS+F group. There was no significant change in skin moisture. Compared to controls, the R2 index of skin elasticity showed improvement in the SS+C group by inter-group analysis (p=0.009). On skin image analysis, the number of face wrinkles bilaterally (−26.6%, p=0.008) in the SS+F group and the number of wrinkles on the right side of the face (−45.5%, p=0.005) in the SS group) showed significant improvement. Although an increase in ultraviolet (UV) spots was seen in the SS and control groups, this increase was significantly attenuated in the SS+C group (inter-group analysis: p‹0.05). Further, compared to controls, there was a significant reduction in the number of red spots in the SS+H group (number:−7.9%, p=0.022, % area: −11.7%, p=0.039). No severe adverse effects were observed during this study.
Conclusion: An improvement in wrinkles was seen in the SS group, with different additional elements displaying benefits in different areas of skin appearance and health. The SS+C group showed beneficial results with regard to elasticity and UV spots, the SS+H group showed beneficial results in red spots, and the SS+F group showed beneficial results in moisture levels and wrinkles.