You can use morning, evening, or both without significant irritation risk
Carnosine An amino acid and potent antioxidant that protects skin firmness and elasticity, while reducing redness and protecting against oxidative stress
J Clin Endocrinol Metab 70:519527 Bianda T, Hussain MA, Glatz Y, Bouillon R, Froesch ER, Schmid C (1997) Effects of short-term insulin-like growth factor-I or growth hormone treatment on bone turnover, renal phosphate reabsorption and 1,25 dihydroxyvitamin D3 production in healthy man
Its a small chain of amino acids (the building blocks of protein) that was originally identified in human stomach (gastric) juice
The video explains how to inject