Semax vs NA-Semax Amidate — what does the literature actually say?

I keep seeing people conflate these two in online forums. They are structurally different — the amidate modification significantly changes the pharmacokinetic profile and potentially the mechanism of action.

NA-Semax Amidate has the N-acetyl group AND the C-terminal amidation, which should theoretically increase both potency and half-life. But the published research is almost entirely on standard Semax.

Has anyone come across actual comparative studies? Or are we all just extrapolating from the structural modifications?