H-Val-Pro-Pro-OH (TFA), a proline peptides derivative, could inhibit Angiotensin I converting enzyme (ACE), with an IC50 of 9 μM. H-Val-Pro-Pro-OH (TFA) could enhance insulin sensitivity and prevent insulin resistance in 3T3-F442A pre-adipocytes. H-Val-Pro-Pro-OH (TFA) also has anti-hypertensive and anti-inflammatory functions. H-Val-Pro-Pro-OH (TFA) further enhances the expression of glucose transporter 4 (GLUT4) in adipocytes and restores glucose uptake in TNF-treated adipocytes.