Human IL‑1α is a vital pro‑inflammatory cytokine encoded by the IL1A gene, belonging to the IL‑1 superfamily and participating in immune reactions, inflammatory cascades and hematopoiesis. It can be recombinantly expressed in Escherichia coli. Predominantly secreted by monocytes, macrophages and dendritic cells, IL‑1α is initially synthesized as a precursor. Upon cellular injury, it undergoes proteolytic cleavage and release to trigger apoptosis, exerting effects via two shared receptors (IL‑1RI and IL‑1RII) also used by IL‑1β. As a pleiotropic mediator, IL‑1α activates NF‑κB and MAPK signaling cascades, upregulates IL‑6 and cyclooxygenase‑2 expression, and boosts nitric oxide production. Physiologically, it is enriched in barrier‑forming tissues including epidermal keratinocytes and pulmonary epithelial cells, acting as an alarm hormone to initiate local inflammation. Additionally, IL‑1α suppresses preadipocyte differentiation, lipid deposition and osteoblast maturation. Given its multifunctional biological roles, recombinant human IL‑1α is extensively applied in basic research. It serves as a key reagent for investigating inflammatory mechanisms, immune regulation, and establishing relevant disease models.