L-Ascorbic acid 2-phosphate magnesium (2-Phospho-L-ascorbic acid magnesium) is a long-acting vitamin C derivative that can stimulate collagen formation and expression. L-Ascorbic acid 2-phosphate magnesium (2-Phospho-L-ascorbic acid magnesium) can be used as a culture medium supplement for the osteogenic differentiation of human adipose stem cells (hASCs). L-Ascorbic acid 2-phosphate magnesium (2-Phospho-L-ascorbic acid magnesium) increases alkaline phosphatase (ALP) activity and expression of runx2A in hASCs during the osteogenic differentiation.