There is no human trial that sets a timeline, so reports are anecdotal and drawn from animal research
Jones AR, Shusta EV
[43] We believe that the updated descriptor accurately reflects the devices intended to be described by C1739, inclusive of the SCOUT MD TM Delivery System, and addresses the applicant's concerns that the prior descriptor was overly broad
[DOI] [PMC free article] [PubMed] [Google Scholar] 34.Aynekulu Mersha D.G., van der Sterren I., van Leeuwen L.P.M., Langerak T., Hakim M.S., Martina B., van Lelyveld S.F.L., van Gorp E.C.M
Yuan et al., 2021)
Brighter, More Even Tone Korean Rice Water and Niacinamide visibly improve skin clarity, reducing dullness and uneven patches with regular use