J Soil Sci Plant Nutr 22:914936 Dong XP, Ma XM, Zhao ZL, Ma M (2024) Exogenous betaine enhances salt tolerance of Glycyrrhiza uralensis through multiple pathways
The Hostynek and Maibach group at UCSF measured exactly this in 2011: human skin permeation of GHK-Cu as a function of skin layer, with the result that the peptide accumulates in the upper stratum corneum but does not pass through to viable epidermis or dermis in any meaningful quantity 4
Experience the Difference of Pure Bioactive Oils Cameron-Smith, D., Albert, B
human clinical trials are rare and preliminary
Overconsumption of Omega-6 polyunsaturated fatty acids (PUFAs) versus deficiency of Omega-3 PUFAs in modern-day diets: the disturbing factor for their "balanced antagonistic metabolic functions" in the human body
They are banned in many European countries