Testicular dysfunction represents a leading cause of male infertility, yet effective therapeutic interventions remain elusive. Here, we report a novel plant-derived nanotherapeutic strategy for testicular injury using Cistanche deserticola-derived exosome-like nanovesicles (CDELNs). CDELNs are preferentially internalized by testicular Sertoli cells via heparan sulfate proteoglycan (HSPG)-mediated endocytosis, whereupon, CDELN-derived miR-159b-3p directly targets the 3'UTR of Cdkn1a mRNA, leading to downregulation of p21 and subsequent alleviation of p21-mediated cell cycle arrest in Sertoli cells. In a mouse model of testicular injury, administration of CDELNs significantly ameliorated testicular histopathology, restored blood-testis barrier integrity, improved sperm quality and key hormone levels, and partially rescued fertility. Notably, reanalysis of publicly available single-cell RNA-seq data from non-obstructive azoospermia (NOA) patients revealed elevated CDKN1A expression in Sertoli cells, suggesting that p21 dysregulation may also contribute to human testicular dysfunction. In summary, our study supports CDELNs as a natural nanovesicle-based candidate that protects against testicular injury through miRNA-mediated p21 suppression, offering a promising translational avenue for male infertility.