Atherosclerosis (AS) and type 2 diabetes (T2DM) are metabolically associated disorders characterized by dyslipidemia or hyperglycemia. Apolipoprotein (Apo)A-I or ApoA-I-derived reconstituted high-density lipoprotein (rHDL)-raising therapies have been proposed beneficial in both pathologies. Currently, high-cost of ApoA-I and complexity in producing rHDL have set financial and manufacturing barriers to HDL-focused therapies. Here, we construct a peptide-based HDL (pHDL) by microfluidics, simply employing dimeric form of ApoA-I mimetic peptide 4F and phospholipids. Morphologically, pHDL adopts nano-discoidal model of HDL. More intriguingly in function, pHDL predominantly triggers activation of adipose tissue browning in both AS and T2DM experimental models, contributing to a potent management of dyslipidemia and hyperglycemia. Activation of fat browning and benefits in both AS and T2DM provide new insights into pHDL as a potential therapeutic candidate to complement current pharmacological arsenals for metabolic defects, and engineering of pHDL will further facilitate clinical translation of synthetic HDL therapies.