**11. Future developments**

The cosmetic industry is still faced with the challenge of developing a more stable formulation and finding a method of transepidermal administration that increases the concentration of vitamin C in the skin, and, therefore, its effectiveness and results.

It has been shown that its oral or intravenous use at high doses, for example, 3 g/ day, favors an increase in its concentration in the buccal mucosa, but its effectiveness on the skin has not been sufficiently clarified; by contrast, it has been observed a reduction in the presence of glutathione (tripeptide with antioxidant action)

*Cosmetic Topical Use of Vitamin C DOI: http://dx.doi.org/10.5772/intechopen.109644*

secondary to the use of doses of vitamin C that exceed the recommendations for daily intake [42].

We have studies that have shown that ultrasound, iontophoresis, fractional lasers of different types, and microdermabrasion can favor the skin penetration of vitamin C, but more research is needed and with larger samples to be able to evaluate the efficacy of using these routes versus topical [43].

Different types of studies are being conducted that allow us to expand the uses of vitamin C in treatments for hair loss, wound healing, scars, skin aging linked to smoking or other factors, and stretch marks [44].
