Effects of a Tubtim Chumphae Rice Extract Facial Serum on Skin Biophysical Properties in Healthy Middle-Aged Adults: A Split-Face Controlled Clinical Trial

This study aimed to investigate the effects of a facial serum containing Tubtim Chumphae rice extract on skin hydration, elasticity, oiliness, pigmentation, and erythema in healthy adults aged 30–50 years. Thirty participants applied two facial serums daily to opposite sides of the face for 12 weeks: (1) a serum containing Tubtim Chumphae rice extract (treatment intervention) and (2) a standard serum formulation containing 2% α-arbutin (control intervention). Skin hydration, elasticity, oiliness, melanin, and erythema were assessed at baseline and after the intervention using non-invasive skin measurement techniques. At baseline, no significant differences were observed between facial sides for any outcome. After 12 weeks, the side treated with the treatment intervention demonstrated significant within-side improvements in skin hydration at the forehead, skin elasticity at the cheeks and chin, and reductions in melanin and erythema in selected facial regions (all p < 0.05). However, paired split-face comparisons revealed that the treatment intervention produced significantly greater skin hydration at the cheek (mean difference = 3.88 AU, 95% CI: 0.23–7.53 AU, p = 0.039) and significantly greater skin elasticity at the forehead (mean difference = 0.090, 95% CI: 0.011–0.169, p = 0.028) compared with the control intervention. In addition, skin oiliness at the cheek was significantly lower on the side treated with the treatment intervention (mean difference = −6.62 µg/cm2, 95% CI: −12.62 to −0.62 µg/cm2, p = 0.032). No significant between-intervention differences were observed for melanin or erythema at any facial region. These findings suggest that topical application of a facial serum containing Tubtim Chumphae rice extract may improve skin hydration and elasticity while reducing skin oiliness in healthy middle-aged adults. However, no significant advantages over a standard 2% α-arbutin serum were observed for skin pigmentation or erythema after 12 weeks of treatment. Clinical Trial Registration: ClinicalTrials.gov, NCT06475222.