In conclusion, we have optimised RBC extraction conditions for nh-PHIP detection of ATP, ADP and AMP and successfully implemented Et₃N buffer to control and stabilize the chemical shifts of ATP. However, despite these advances, ATP, ADP and AMP remained undetectable in healthy human plasma. This work presents the first nh-PHIP spectra of both RBC and plasma, a significant step towards sensitivity-enhanced blood-based NMR metabolomics, offering new opportunities to understand human health at the molecular level.