The science
The cream's evidence is the evidence for its active, its pairing ingredient and its format, and all three are published. The active, niacinamide, was tested in a 2005 Dermatologic Surgery trial in which a five percent moisturiser applied to one side of the face for twelve weeks, against vehicle on the other, produced measurable improvements in fine lines and wrinkles, hyperpigmentation, red blotchiness, sallowness and elasticity. Japan's health ministry recognises niacinamide as a quasi-drug active for wrinkle improvement and for suppressing melanin production, and registration constrains the concentration to the range those approvals were granted at; Rohto does not print it, but the dual claim implies a working dose.
The pairing ingredient has its own trial. A 2010 randomised, double-blind, vehicle-controlled study in the British Journal of Dermatology compared a moisturiser containing niacinamide and N-acetyl glucosamine with niacinamide alone and with vehicle in women with facial hyperpigmentation and found the combination reduced the appearance of pigmentation more than either comparator over eight weeks, an effect attributed to the two molecules acting on different steps of melanin synthesis and transfer. Acetyl glucosamine in this cream is that amino sugar, and its inclusion is the most evidence-directed decision in the formula.
The format contributes the overnight effect. Shea butter and a hydrogenated vegetable oil are occlusive lipids that reduce transepidermal water loss while the three hyaluronic acids, glycerin and butylene glycol hold water in the stratum corneum, which is the mechanism behind plumper, smoother skin by morning and the temporary softening of fine dehydration lines. Pullulan is a fermentation-derived polysaccharide that forms a thin film with mild contractile tightening as it dries, well documented as a cosmetic firming agent and honestly transient. Delta-tocopherol protects the lipid phase from oxidation. The absence of fragrance, alcohol and parabens removes the three ingredients most often implicated in cosmetic intolerance; Amur cork tree bark extract has keratinocyte studies showing anti-inflammatory activity and no clinical data at cosmetic doses. The remaining caveat is the label's silence on percentage, which leaves the dose inferred from the registration rather than read.
References 2 ShowHide
- Niacinamide: A B vitamin that improves aging facial skin appearance — Dermatologic Surgery (2005)
- Reduction in the appearance of facial hyperpigmentation after use of moisturizers with a combination of topical niacinamide and N-acetyl glucosamine: results of a randomized, double-blind, vehicle-controlled trial — British Journal of Dermatology (2010)