Despite the marketing, topically applied collagen doesn't "refill" the collagen in your skin
For example, glutathione-S-tranferase gene polymorphisms confer reduced risk in pancreatic cancer (Jiao et al., 2007)
When you say "must be injected immediately after mixing", I've heard that you need to let it sit for 10min after mixing it before injecting
Okazaki M, Fushida S, Tsukada T, Kinoshita J, Oyama K, Miyashita T, et al
FGF18 as a prognostic and therapeutic biomarker in ovarian cancer
Considering the immunomodulation and antioxidant of selenium, selenium ad-ministration in critically ill patients has been explored as a potential therapeutic intervention