Topical Vitamin C?
A cream or ointment? Or just vitamin C powder mixed with water?
And how long was it on?
They said
vitamin C (C E Ferulic with 15% L-ascorbic acid - skinCeuticals)
Described the details of use in the ‘Patients and Methods’ section of the paper.
Natural African Shea Butter is very nourishing to the skin and over time can fade dark spots which it did for mine. There are also cosmetics with Shea Butter for hair and skin. More information at Google