Background. We previously demonstrated that the human amniotic fluid from the II trimester of gestation is a feasible source of stromal progenitors (namely human amniotic-fluid derived stem cells, hAFSC), endowed with significant paracrine potential for regenerative medicine. Extracellular vesicles (EVs) separated and concentrated from the hAFSC secretome can deliver pro-survival, proliferative, anti-fibrotic, and cardioprotective effects in different rodent preclinical models of cardiac and skeletal muscle injury. Yet, hAFSC-EV isolation may be significantly influenced by in vitro cell culture; thus, growing interest has recently been addressed in profiling of EVs directly concentrated from human amniotic fluid samples (hAF) as an alternative option. Here we provide a detailed characterization of II trimester hAF-EVs and we investigate their paracrine potential against oxidative stress as a hallmark of cardiac and skeletal muscle dysfunction. Methods. II trimester hAF samples were obtained as leftover material from prenatal diagnostic amniocentesis. EVs were separated by size exclusion chromatography and concentrated by ultracentrifugation. hAF-EVs were then assessed by nanoparticle tracking analysis, transmission electron microscopy, Western Blot and flow cytometry. hAF-EV metabolic activity was evaluated by oximetric and luminometric analyses and their cargo profiled by proteomics and RNA sequencing. hAF-EV paracrine potential was tested in two different preclinical models of oxidative stress and dysfunction in vitro on murine C2C12 cells and on 3D human cardiac micro tissue. Results. Our protocol resulted in a yield of 6.31±0.98x109 EV particles per hAF millilitre showing round cup-shaped morphology and 209.63±6.10 nm average size, with a relevant expression of CD81, CD63, and CD9 tetraspannin markers. hAF-EVs were found enriched in CD133/1, CD326, CD24, CD29, and SSEA4 and able to produce ATP by oxygen consumption. While oxidative stress significantly reduced C2C12 survival, hAF-EVs priming resulted in almost complete rescue in cell viability, with notable recovery of ATP synthesis and concomitant reduction of cell damage and lipid peroxidation activity. 3D human cardiac microtissues treated with hAF-EVs and experiencing H2O2 stress and TGFbeta stimulation, showed considerable improvement in viability with remarkable decrease of fibrosis onset. Conclusions. Our results suggest that leftover samples of II trimester human amniotic fluid can represent a feasible source of EVs to counteract oxidative damage on target cells, thus offering a novel candidate therapeutic option to counteract skeletal and cardiac muscle injury.