FOXO4-DRI
Also known as FOXO4 D-Retro-Inverso peptide, FOXO4-DRI, Proxofim
FOXO4-DRI is a D-retro-inverso peptide designed around the FOXO4-p53 interaction, used as a tool in cellular senescence and senolytic research. A research-use profile: format, design rationale, and handling.
FOXO4-DRI is best understood as a designed research tool rather than a natural signaling peptide. Its name encodes its purpose: it is modeled on a segment of the FOXO4 protein, and it is manufactured in the D-retro-inverso (DRI) format — D-amino acids in reversed order — to make it more stable and useful in the lab.
The reason it appears in the longevity conversation at all is the biology it was designed to probe: the interaction between FOXO4 and the p53 protein inside senescent cells. That places FOXO4-DRI squarely in the senescence and 'senolytic' research area. This page describes the peptide's design and that research context, and makes no claims about outcomes.
FOXO4-DRI is a synthetic peptide built in the D-retro-inverso format: it uses D-amino acids assembled in reverse order relative to the natural sequence. That construction is deliberate — retro-inverso peptides can present a similar surface to their target while resisting the enzymes that would rapidly break down a normal L-peptide, which is why they are favored as research tools.
What 'D-retro-inverso' means
A standard peptide is a chain of L-amino acids read in a fixed direction. A retro-inverso peptide reverses the sequence order and swaps the amino acids to their D (mirror-image) forms. Done together, these two inversions can leave the molecule presenting a comparable arrangement of side chains to its target while being far more resistant to the proteases that would chew up an ordinary peptide.
This is why FOXO4-DRI is written with the 'DRI' tag: the format is the whole point. It is what lets researchers use a peptide modeled on a natural sequence as a durable experimental probe.
The FOXO4-p53 interaction it targets
FOXO4-DRI was designed around the interaction between FOXO4 and p53, two proteins that come up in the biology of senescent cells — cells that have stopped dividing but persist in tissue. Interfering with that protein-protein interaction is the mechanism researchers use FOXO4-DRI to explore.
Because senescent-cell biology is a central theme of aging research, FOXO4-DRI is discussed as a 'senolytic' research tool — a molecule studied in the context of clearing or probing senescent cells. That is a research context, not a promised effect.
These are research areas the compound is associated with in the literature — not medical claims or intended uses.
Handling & storage
Supplied lyophilized. Kept sealed and cold; in research settings it is reconstituted with bacteriostatic water only when a protocol requires it, then refrigerated. Handle per accepted laboratory practice.
Verify a certificate by lot →Common questions
D-Retro-Inverso — the peptide is made from D-amino acids arranged in reverse order relative to the natural sequence. This format is chosen to make the molecule more resistant to breakdown so it works better as a research tool.
The interaction between the FOXO4 and p53 proteins, which is relevant to senescent cells. That connection is why FOXO4-DRI is discussed as a senolytic research tool.
No. It is a fully synthetic, engineered peptide. Its D-retro-inverso construction does not occur naturally and is specifically designed for laboratory stability.
This monograph is a research-use reference. It describes composition and the contexts in which the compound has been studied — it is not medical advice, a description of effects, or a recommendation for use. Sold strictly for laboratory and research use; not for human or animal consumption.