The science
For a two-dollar sheet this formula touches three separate bodies of evidence, and it is worth being clear about how much of each it can claim. The most solid is arbutin's. Arbutin is a glycoside of hydroquinone that competitively inhibits tyrosinase, the rate-limiting enzyme in melanin synthesis, and controlled trials of leave-on arbutin at concentrations of a few percent show measurable lightening of melasma and post-inflammatory hyperpigmentation over eight to twelve weeks. Its third-place listing here indicates a functional level for a rinse-free essence, but the relevant caveats are contact time, twenty minutes rather than all day, and frequency, a few times a week rather than twice daily, so the reasonable expectation is a small contribution to preventing fresh marks from setting rather than the fading of established ones.
The centella evidence is more specific than the marketing usually admits. The clinical work supporting centella for redness, wound healing and post-procedure recovery was done with standardised triterpene fractions, and madecassoside in particular has been studied in leave-on preparations for reducing erythema and transepidermal water loss and for supporting collagen synthesis in healing skin. Its inclusion here as a named ingredient at twelfth position matters more than the culture extract above it: callus culture media are unstandardised in triterpene content, and Coreana's disclosed 500 ppm describes the medium, not its active fraction. Dipotassium glycyrrhizate, the licorice-derived glycyrrhizin salt, has anti-inflammatory data in topical use through inhibition of inflammatory mediators and is a standard pairing in Korean calming formulas. Allantoin and panthenol, at seventh and eighth, carry the best-established soothing and hydration records in the formula and are present at positions consistent with the concentrations those records used.
The absences are also evidence-based. Fragrance remains the most common contact allergen class in cosmetics, and ethanol and exfoliating acids measurably increase transepidermal water loss on compromised skin, so an oil-free, fragrance-free, acid-free gel is the format the post-procedure literature favours for the first days of recovery. Sheet-mask studies as a class show a substantial short-term rise in stratum corneum hydration that returns toward baseline within a day, which is the honest ceiling on what any single use here achieves. The fruit and flower extracts at the end of the list have no evidence at their positions. On balance, a calming sheet with a defensible mechanism for each of its claims and an unclaimed one for brightening, all at doses that make the effects real but small.