F1, an anti-inflammatory peptide, incorporates the HIV-1 Tat protein transduction domain linked with a 15-amino acid sequence from residues 46-60 of the inhibitor of NF-κB kinase-interacting peptide (IKIP). It effectively blocks LPS-induced phosphorylation of IκB kinase α (IKKα) and IKKβ, along with the nuclear translocation of NF-κB (p65) in mouse peritoneal macrophages at 5 µM concentration. F1, administered at 5 mg/kg in vivo, significantly reduces IL-6, TNF-α, and IL-1β serum levels and enhances survival in a mouse sepsis model induced by LPS.