There is a thought, among scientists, that GHK-Cu may protect nervous system tissues against natural insults such as gene dysregulation and that it is the decline in GHK-Cu with age, and not the onset of new disease processes, that actually leads to neurodegeneration
Physiological Reviews, 79 (2), 511 607
LDL, lowdensity lipoprotein
Adherence rates for oral formulations are typically 5-10% lower than injectables due to administration complexity and GI side effects (nausea, constipation, diarrhea)
Scientists have not given up on the drugs for these conditions, but they will need to pivot, focusing on new GLP-1 research questions spurred by the trials results