Clearly this will vary considerably, but cross-cultural data suggests that preferred inter-personal distances between strangers are 135 cm, compared with 92 cm between acquaintances and 32 cm between close people, with women usually preferring larger distances than men (Sorokowska et al., Reference Sorokowska, Sorokowski, Hilpert, Cantarero, Frackowiak, Ahmadi and Pierce2017)
Effective concentrations range from 0.5% to 2%
It is not FDA approved yet in the United States for skin lightening
That access rule is the downside for individuals, since a solo researcher cannot simply check out the way they can at a retail vendor, even though the catalog itself is impressive
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