I don't know first hand but would expect plants to take them up through the roots and the decrease in energy otherwise required to synthesise them to be conserved. I'm interested in why we might go down such a track.
It has been found that grain yield of wheat has increase by 5.4% and 11%, respectively, for the application of AminoPrim at a dose 1.0 L/ha and AminoHort at dose 1.25 L/ha, when compared to the control group without biostimulant. Amino acid application cannot compensate the fertilizer application only it can work as biostimulant. The only advantage we get that amino acid fertilizers are readily absorbed, transported, and utilized as a source of nitrogen and carbon for plants.