References

1. Song H, Zhang S, Zhang L, Li B. Effect of orally administered collagen peptides from bovine bone on skin aging in chronologically aged mice. Nutrients. 2017;9(11):1209.
   doi: 10.3390/nu9111209
   Read more

2. Geesin JC, Darr D, Kaufman R, Murad S, Pinnell SR. Ascorbic acid specifically increases type I and type III procollagen messenger RNA levels in human skin fibroblast. J Invest Dermatol. 1988;90(4):420-4.
   doi: 10.1111/1523-1747.ep12460849
   Read more

3. Oe M, Sakai S, Yoshida H, et al. Oral hyaluronan relieves wrinkles: a double-blinded, placebo-controlled study over a 12-week period. Clin Cosmet Investig Dermatol. 2017;10:267-273.
   doi:10.2147/CCID.S141845
   Read more

4. Kawada C, Yoshida T, Yoshida H, et al. Ingestion of hyaluronans (molecular weights 800k and 300 k) improves dry skin conditions: a randomized, double blind, controlled study.
   J Clin Biochem Nutr. 2015;56(1):66-73.
   doi: 10.3164/jcbn.14-81
   Read more

5. Min D, Park S, Kim H, et al. Potential anti-ageing effect of chondroitin sulphate through skin regeneration. Int J Cosmet Sci. 2020;42(5):520-527.
   doi: 10.1111/ics.12645.
   Read more

6. Nichols JA, Katiyar SK. Skin photoprotection by natural polyphenols: anti-inflammatory, antioxidant and DNA repair mechanisms. Arch Dermatol Res. 2010;302(2):71-83.
   doi: 10.1007/s00403-009-1001-3
   Read more

7. Mantena SK, Katiyar SK. Grape seed proanthocyanidins inhibit UV-radiation-induced oxidative stress and activation of MAPK and NF-kappaB signaling in human epidermal keratinocytes. Free Radic Biol Med. 2006;40(9):1603-14.
   doi:10.1016/j.freeradbiomed.2005.12.032
   Read more