Beta-carotene is effective in protecting the skin from the harmful effects (solar erythema or sunburn) of ultra-violet (UV) rays as demonstrated in various studies
Shoshani O, Livne E, Armoni M, Shupak A, Berger J, Ramon Y, Fodor L, Gilhar A, Peled IJ, Ullmann Y
Its not exactly inexpensive
B12 shots can be both subcutaneous and intramuscular
Exercise Performance : Studies suggest that MOTS-c can enhance physical endurance and recovery, making it ideal for athletes or anyone seeking to optimize performance
GHK-Cu has more extensive human clinical research, particularly in dermatological applications