Instrumental Assessment of a Chemical Skin Biostimulator Combining Ammonium Trichloroacetate and Homocysteic Acid in...

Mature photoaged skin is characterised by concurrent deterioration of dermal extracellular matrix, impairment of the epidermal barrier and dysregulated melanogenesis. Chemical skin biostimulators that remodel the dermis without inducing overt exfoliation may offer a multimodal alternative to conventional peels. In this single-arm, prospective study, 25 women with Fitzpatrick phototype II and clinical signs of facial photoageing received four sessions of a homocysteic acid (HoA)-containing chemical biostimulator incorporating ammonium trichloroacetate (ATCA), and phytic and citric acids accompanied throughout by a standardised home-care regimen. Instrumental endpoints included viscoelasticity assessed by Cutometer, three-dimensional wrinkle volume and texture quantified by Antera 3D, grey-level co-occurrence matrix (GLCM) metrics for hyperpigmentation, and sebum and hydration measurements; tolerability was assessed by clinical inspection at each visit, although safety was not a pre-specified endpoint. All three Cutometer elasticity parameters increased by approximately 24% and remained significantly improved at 12 weeks, with a continued rise in biological elasticity (R7), a temporal pattern compatible with progressive dermal remodelling, although no histological verification was undertaken. Antera 3D documented a rapid (50-62%) reduction in wrinkle volume and texture roughness at 2 weeks, followed by a partial regression stabilising at 79-83% of maximal improvement at 12 weeks. In the hyperpigmented subgroup (n = 14), GLCM contrast decreased and homogeneity increased by 18-19%, indicating more uniform reflectance and reduced optical heterogeneity, with effects persisting at 12 weeks. Hydration improved and sebum secretion decreased; no serious adverse event was observed or reported, although adverse events were not recorded systematically. In this uncontrolled, single-arm study, a protocol based on a HoA-containing chemical skin biostimulator was associated with durable improvements in instrumentally assessed dermal elasticity and a partially reversible, yet sustained, enhancement of wrinkles, texture and hyperpigmentation in mature photoaged skin. The mechanisms proposed to underlie this profile-neocollagenesis and remodelling of the extracellular matrix, barrier restoration and modulation of melanogenesis-are interpretative rather than directly demonstrated. Because a combined commercial formulation was evaluated within a protocol that included a standardised home-care regimen, the observed changes cannot be attributed to any individual ingredient, including HoA, and the contribution of the home-care regimen cannot be separated from that of the in-office treatment. The absence of a control arm precludes causal attribution, and these findings-obtained in a small cohort of Fitzpatrick phototype II women, with a hyperpigmentation subgroup of only fourteen-should be regarded as hypothesis-generating.