Vitamin C is found in a wide variety of fruit and vegetables. Good sources include: Citrus Fruit such as Oranges and Orange Juice, Peppers, Strawberries, Blackcurrants, Broccoli, Brussels sprouts, Potatoes.
Vitamin C is one of the best ingredients incorporated in the skincare regimen due to its powerful antioxidant properties to reduce premature signs of skin aging and brown spots.

The main active forms of vitamin C are Magnesium Ascorbyl Phosphate and L-Ascorbic Acid. Magnesium Ascorbyl Phosphate is a water-soluble vitamin C derivative that is more stable in water. L-Ascorbic Acid is the body's most important intracellular and extracellular aqueous-phase antioxidant.

Potent Antioxidant
Being an antioxidant, Vitamin C protects the skin from free radical damage that disrupts the cellular structure of the skin such as loss of collagen and elastin. Combining vitamin C and broad-spectrum sunscreens that protect well against UV rays is more effective at neutralizing free radical damage from sun exposure than just using sunscreen alone. This combination offers great additive protection against photo-toxic damage.

It’s important to note that Vitamin C does not work as a barrier to UV rays. Rather, once rays enter the skin, it slows the rate of free radical damage to collagen and aids in skin repair by reducing oxidation damage to the skin cells. It also evens pigmentation and decreases fine lines by stimulating collagen production. Test results confirm the use of antioxidants as photo-protectant and emphasize the importance of combining the compounds of sunscreen with Vitamin C to maximize photoprotection.

How Antioxidants Reduce Free Radicals

Vitamin C is safe to use in cosmetic products.

https://online.personalcarecouncil.org/ctfa-static/online/lists/cir-pdfs/PRS278.pdf

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3783921/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3673383/

https://pubmed.ncbi.nlm.nih.gov/8869680/

https://www.ncbi.nlm.nih.gov/books/NBK537164/