The science
The hydration in this cream comes from three layers that work in sequence, and the hyaluronic acid on the label is the smallest of them. The first layer is classic humectancy: glycerin and propanediol at the top of the list, with urea, trehalose and serine further down, all of which are natural moisturizing factor components or their analogues that draw water into the corneocytes and hold it there. Urea in particular has a long clinical record for improving stratum corneum hydration at low percentages, and its placement just ahead of the fragrance suggests a humectant rather than keratolytic dose. The second layer is a light occlusive film from the C15-19 alkane, caprylic/capric triglyceride and dimethicone, plus the cellulose and acrylate polymer network ISDIN calls its 3D-Hydrating Complex, which slows transepidermal water loss without the heaviness of petrolatum. Panthenol, at eleventh position, adds barrier support with well-documented effects on hydration and irritation.
The hyaluronic acid is the third layer and the one the science on molecular weight speaks to most directly. A randomised, vehicle-controlled study published in the Journal of Drugs in Dermatology in 2011 applied 0.1% hyaluronic acid creams of five molecular weights, from 50 to 2000 kDa, to the periocular skin of 76 women twice daily for 60 days; every weight significantly improved hydration and elasticity over vehicle, while only the two lowest weights, 50 and 130 kDa, produced a significant reduction in wrinkle depth, which the authors attributed to better penetration. This cream's pairing of sodium hyaluronate with hydrolyzed hyaluronic acid follows that logic, a higher-weight film-former for surface water retention and a low-weight fraction that reaches further into the stratum corneum. Both are present in small amounts, which is normal for HA, but it does mean the cream's persistence through the day is mostly the work of the humectants and film above them.
The botanicals are marketing-forward. Vigna aconitifolia seed extract has preliminary in vitro data suggesting retinoid-like gene expression effects and very little human evidence at cosmetic concentrations; Camellia japonica flower extract contributes polyphenol antioxidants alongside the tocopherol already present; Alteromonas ferment extract is sold as an anti-pollution film-former with supplier data behind it. ISDIN's 57% two-hour hydration figure comes from a 24-subject corneometry test and its perception percentages from a 30-subject, seven-day panel, both brand-run and small, though consistent with what a humectant-rich cream of this design would be expected to do.
References 1 ShowHide
- Efficacy of cream-based novel formulations of hyaluronic acid of different molecular weights in anti-wrinkle treatment — Journal of Drugs in Dermatology (2011)