The STEP 1 trial extension has excellent data shown above to answer this question
Repeat testing or additional evaluation may sometimes be recommended
30mL bottle3% GHK-Cu Research watchlist Get updates when availability, evidence, or category guidance changes for GHK-Cu Topical Serum
And so my focus was, I said, okay, if I want to, if I want to have a fighting chance for my skin to look better, I need all those ingredients inside
doi: 10.1016/j.trsl.2020.03.012, Summary Keywords aging, exercise, L-citrulline, leucine, musclevasculature, cognitive frailty, successful aging, neurovascular coupling Citation Lin X, Zhang Y, Pu J and Peng Y (2026) Targeting musclevasculature crosstalk in aging through the integrative roles of L-citrulline, leucine, and exercise: focus on muscle metabolism, vascular function, and sarcopenia prevention