FOXO4-DRI has no published human study. Three bulk listings in FDA's drug directory carrying its name register a cat-allergen peptide as the ingredient.

The molecule

A mirror-image peptide with a delivery tag bolted on

The 2017 Cell paper that introduced the compound gives its full composition. FOXO4-DRI is the sequence ltlrkepaseiaqsileaysqngwanrrsggkrppprrrqrrkkrg in D-isoform, molecular weight 5358.2, manufactured for that study by Pepscan in the Netherlands at greater than 95% purity.[2] Two design choices are worth separating. The first is the D-retro-inverso construction: the authors note that L-peptide domains can sometimes be mimicked using D-amino acids in a retro-reversed sequence, a modification that can change a peptide's chemical properties.[2] The second is the tail. The authors write that to facilitate cellular uptake, the peptide "was designed as a fusion with HIV-TAT, a basic and hydrophilic sequence which allows energy-independent cellular uptake of cargo through transient pore formation."[2] Part of the molecule is therefore a delivery tag rather than the FOXO4-derived region, and the paper stored it in 1 mg aliquots at -20°C to avoid freeze-thaw artefacts.[2]

Vendors also sell it as proxofim.[18] That name returns zero records in PubMed as of November 6, 2026.[17]

The founding study

What the 2017 paper reported, and in what

Baar and colleagues published Targeted Apoptosis of Senescent Cells Restores Tissue Homeostasis in Response to Chemotoxicity and Aging in Cell on March 23, 2017.[2] The abstract's claims are specific: the peptide perturbs the FOXO4 interaction with p53, which in senescent cells "selectively causes p53 nuclear exclusion and cell-intrinsic apoptosis", and in mice it neutralised doxorubicin-induced chemotoxicity and "restored fitness, fur density and renal function" in fast-aging XpdTTD/TTD mice and in naturally aged mice.[2]

The administered amounts are in the figure legends rather than the abstract. For the chemotoxicity experiment the legend reads "Doxorubicin: 2× i.p. at 10mg/kg. FOXO4-DRI: 3× i.v. at 5mg/kg, every other day (day 1, 3 and 5)"; the naturally aged animals were assessed 30 days after three intraperitoneal injections of 5 mg/kg on alternating days.[2] Those figures are reported here with their source and their population, which is mice. The paper's tolerability language is likewise bounded to animals: results were obtained "under conditions where it was well tolerated in vivo".[2] PubMed's record for the paper carries no retraction or erratum notice, only commentaries.[21]

One search artefact is worth flagging for anyone repeating this work: the original paper's indexed abstract says "FOXO4 peptide", not "FOXO4-DRI", so a literal search for the trade-style name returns the accompanying Cell preview, Rejuvenation by Therapeutic Elimination of Senescent Cells, but not the research article itself.[1]

The human line

Human cells in a dish, never a person

A PubMed search for "FOXO4-DRI" on November 6, 2026 returned 19 records; a broader search combining FOXO4 peptide terms with senescence returned 21, adding the founding paper and two successor-peptide papers.[1] Reading the set, the literature is mouse work and cell work: aged-mouse Leydig cells and testosterone, aged-mouse spermatogenesis, bleomycin lung fibrosis, radiation injury, aortic aging in naturally aged and progeroid mice.[6][7][8]

Two studies come closest to people, and both stop outside the body. A 2021 study treated chondrocytes expanded from healthy human donors and reported that the peptide "removed more than half of the cells" at population doubling level 9 while not significantly affecting the number of minimally expanded cells, and that it did not enhance their cartilage-forming potential in pellet culture.[9] A 2025 study in Communications Biology applied it to keloid organ cultures and fibroblasts taken from consenting patients.[10] Human tissue in a laboratory is not administration to a person.

ClinicalTrials.gov on November 6, 2026 returned no study for "FOXO4-DRI", none for proxofim and none with FOXO4 as a registered intervention.[14] A 2026 narrative review in Naunyn-Schmiedeberg's Archives of Pharmacology argues the FOXO4-p53 axis is a target for brain aging, and its own sentence on human data is the tell: the "preliminary human studies" it cites involve FOXO4-axis modulators, such as high-dose fisetin, which is a different compound, not the peptide.[13]

The contrary result

A 2023 Circulation paper where clearing senescent cells made things worse

Senolytic reporting tends to collect positive animal findings. One paper cuts the other way and belongs in the record. In Circulation in 2023, Born and colleagues cleared senescent cells in pulmonary hypertension models by several methods, including a suicide gene, the drug ABT263 and FOXO4-DRI.[5] Clearance by suicide gene or ABT263 increased right ventricular systolic pressure and the hypertrophy index and markedly reduced pulmonary endothelial cells; hemodynamic deterioration and endothelial-cell loss also occurred in serotonin-transporter-overexpressing mice given either ABT263 or FOXO4-DRI, against relevant controls.[5] The authors' conclusion is that eliminating senescent pulmonary endothelial cells by senolytic interventions "may worsen pulmonary hemodynamics".[5] That is a mouse and rat result, like the favourable ones, and it points the opposite way.

Where the science went

The company tied to the 2017 authors develops two other molecules

A 2025 Nature Communications structural paper on the FOXO4-DRI and p53 interaction was partly funded by Cleara Biotech, and its competing-interest statement discloses that the senior author of the 2017 paper and one co-author hold shares in Cleara and hold a published patent describing compounds that bind p53 and inhibit the FOXO4-p53 interaction.[4] The company's own site, read on November 6, 2026, describes two optimised lead development candidates, CL04177 and CL04183, directed at cancer cells with impaired p53 signalling, reporting favourable pharmacokinetics and a maximum tolerated dose "well above their efficacious dose" in mice, and a development strategy "towards clinical trials in solid tumors as well as hematological malignancies" with no phase or date given.[11] The site does not name FOXO4-DRI.[11]

Other laboratories have done the same thing, which is to design around the original rather than take it forward. A 2021 EBioMedicine group modelled the FOXO4-TP53 interaction to produce a new peptide, ES2, patented by authors who are members of a company working on it.[3] A 2025 Journal of Medicinal Chemistry group reported an optimised inhibitor with reduced negative charges and "l-amino acid composition, and shorter length".[12] Nine years on, the molecule being sold is the first draft.

Regulatory status

A listing in an FDA database is not an approval

A search of Drugs@FDA through openFDA on November 6, 2026 returned no product with FOXO4 as a generic name.[15] FOXO4-DRI appears in none of the three categories of FDA's 503A bulk drug substance nominations list, updated May 14, 2026, which pepmg read page by page, and it is not among the six peptide bulk drug substances covered by the HHS enforcement-discretion policy announced in the Federal Register on October 30, 2026.[19][20][22] pepmg did not check the 503B list.

The National Drug Code directory is a different thing, and it does return matches. Three entries, product codes 87079-003 and 87079-500 from BioBloom Inc. and 87327-200 from Sobei Genomics, carry the generic name FOXO4-DRI Synthetic Peptide, marketing category BULK INGREDIENT, dosage form powder, each packaged as 25 g, with listing expiration dates in December 2026 and December 2027.[15] FDA's own page on the directory says that assignment of an NDC number "does not in any way denote FDA approval of the product" and that inclusion "does not indicate that FDA has verified the information provided"; establishments submit the listings themselves.[16]

There is a further oddity in the records. In all three entries the registered active ingredient is not a FOXO4-derived sequence but "CAT FEL D 1 SYNTHETIC PEPTIDE (CPAVKRDVDLFLT)" at a strength of 1 g/g, the standardised name of a cat-allergen peptide, and no FOXO4 unique ingredient identifier is attached.[15] pepmg reports what the database records say and makes no claim about what is in any container; the mismatch is in the listing. Searched the same day, the two labelers' other bulk listings cover NAD and NADH, and a "Telomerase (Synthetic Peptide / Protein)" powder.[15]

The market

Twenty-one vendors, thirty listings

pepmg's price index generated November 5, 2026 shows FOXO4-DRI at 21 vendors in 30 listings, of which 29 are single-compound and one is a three-compound blend.[18] Eighteen of the single-compound listings are 10 mg; the rest are 14, 15 or 19 mg vials, or multi-vial packs totalling 50 and 100 mg.[18] For comparison, the founding study stored the peptide in 1 mg aliquots and injected mice at 5 mg per kilogram.[2]

Those counts are a market snapshot, not evidence about the molecule. Nothing in the published record establishes what one of these products does in a person, and no published study has given this peptide to one.[1][14]

Questions people are asking