Foxo4-DRI vs NAD+

D-retro-inverso peptide that disrupts Foxo4/p53 interaction in senescent cells; restores p53-mediated apoptosis selectively in senescent cells; clears cellular "zombie cells"

FOXO4-DRI is a synthetic D-amino acid retro-inverso (DRI) peptide that disrupts the interaction between the FOXO4 transcription factor and p53 in senescent cells, triggering apoptosis selectively in cells with an activated senescent secretory phenotype (SASP) while sparing non-senescent cells in which this interaction is not tonically antiapoptotic. In senescent cells, overexpressed FOXO4 sequesters p53 in the nucleus and prevents it from initiating apoptosis, enabling the persistence of metabolically active senescent cells that secrete pro-inflammatory SASP cytokines; FOXO4-DRI competitively disrupts this FOXO4-p53 interaction, freeing p53 to activate its apoptotic transcriptional program specifically in cells where the FOXO4 sequestration is functionally relevant. The foundational study published in Cell demonstrated that FOXO4-DRI selectively induced apoptosis in senescent cells in vivo in mice, restoring tissue homeostasis in both chemotherapy-induced and naturally aged animals; subsequent molecular modeling work has characterized the FOXO4-TP53 interaction interface to guide further senolytic peptide design, though published evidence in humans is absent and the preclinical literature remains limited. FOXO4-DRI is a research compound with no regulatory approval in any jurisdiction; it has been studied only in preclinical animal models, and no human pharmacokinetic, safety, or clinical efficacy data has been established.

NAD+ is a coenzyme central to cellular energy metabolism, serving as an electron carrier in glycolysis, the citric acid cycle, and oxidative phosphorylation. It is also a required substrate for sirtuins (SIRT1–7) and PARP enzymes, which regulate DNA repair, gene expression, and mitochondrial biogenesis. NAD+ levels decline measurably with age; IV or subcutaneous delivery aims to restore intracellular pools more directly than oral precursors such as NMN or NR.

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every cell, central to energy production, DNA repair, and sirtuin activation. While not a peptide in the traditional sense, it is widely administered by functional medicine and longevity providers via intravenous infusion or subcutaneous injection. Research interest centres on its role in mitochondrial health, cellular resilience, and neurological function as NAD+ levels decline with age. NAD+ IV therapy: intravenous NAD+ infusion is the administration route that has attracted the most clinical interest, particularly in longevity and functional medicine contexts. IV NAD+ therapy delivers the compound directly into the bloodstream, bypassing digestive absorption — a route considered relevant given that oral NAD+ precursors (NMN, NR) have variable bioavailability. NAD+ IV therapy cost typically ranges from $200–$1,000 per session depending on the clinic, infusion volume, and geographic market; treatment frequency in clinical settings commonly ranges from weekly to monthly maintenance infusions following an initial loading protocol. NAD+ IV therapy clinics operate across major US markets including Houston, Los Angeles, New York, and Las Vegas. For those researching where to find NAD+ IV therapy providers, PeptideBase maintains a directory of verified clinics and telehealth platforms offering NAD+ protocols.