FOXO4-D-Retro-Inverso peptide, also known as FOXO4-DRI, Proxofim, is a 25-amino acid research single synthetic d-retro-inverso peptide. CAS Number: 2460055-10-9. Molecular weight: 5358.06 Da. Sequence: H-LTLRKEPASEIAQSILEAYSQNGWANRRSGGKRPPPRRRQRRKKRG-OH (all D-enantiomer retro-inverso); C₂₂₈H₃₈₈N₈₆O₆₄.

Selective induction of apoptosis in senescent cells (Baar et al., *Cell* 2017); senescent Leydig cells in age-related hypogonadism models (Zhang et al., *Aging* 2020); senescent chondrocytes (*Front. Bioeng. Biotechnol.* 2021); pulmonary fibrosis models (*J. Cell. Mol. Med.* 2022); NSCLC radiosensitization via senescence-like fibroblasts (*JCI Insight* 2021) All findings referenced are from preclinical and in vitro studies. No approved clinical applications exist for this research compound.

-20°C, desiccated, protected from light and moisture (standard for lyophilized research peptides) Avoid repeated freeze-thaw cycles. Once reconstituted, the solution should be refrigerated at 2-8°C and used within 28 days.

Peptide.co’s FOXO4 has been verified at 98.9% purity through independent third-party HPLC testing. The current batch (Lot #YPB.255, 10mg) includes a full Certificate of Analysis confirming identity, purity, and peptide content. All COAs are publicly available at coa.peptide.co. Testing covers HPLC purity analysis, mass spectrometry identity confirmation, heavy metals screening (<20 ppb), and microbial limits (TAMC/TYMC: 0 CFU). All products are manufactured in FDA-registered facilities in the United States.

Disrupts FOXO4-p53 protein interaction specifically in senescent cells, causing p53 nuclear exclusion, mitochondrial translocation, and apoptosis induction (Wikipedia; GenOracle PDF) These mechanisms have been characterized in preclinical models only.

FOXO4 is supplied as a lyophilized (freeze-dried) powder and must be reconstituted before use in research applications. The standard reconstitution solvent is bacteriostatic water (sterile water containing 0.9% benzyl alcohol). When reconstituting, direct the solvent gently along the inside wall of the vial — do not spray directly onto the lyophilized powder. Allow the peptide to dissolve naturally without shaking or vortexing. For detailed reconstitution volume calculations, use the free Bacteriostatic Water Calculator or Peptide Reconstitution Calculator on Peptide.co.