What does D-retro-inverso mean?

The sequence is reversed and built from mirror-image amino acids. The resulting molecule presents a similar shape to its target while being nearly invisible to the enzymes that would destroy an ordinary peptide, so it lasts far longer.

Are senolytics a real field?

Yes, and an active one. Several small molecules are in early human trials for age-related conditions. This peptide is not among them, and being part of a legitimate research direction is not the same as being tested.

Anti-aging & longevity

FOXO4-DRI

FOXO4-D-Retro-Inverso · Senolytic peptide

PreclinicalReviewed 18 Aug 2026

FOXO4-DRI comes from one genuinely striking piece of science. Senescent cells are cells that have stopped dividing but refuse to die, accumulating with age and secreting inflammatory signals. This peptide disrupts the interaction that keeps them alive, and in a 2017 study aged mice treated with it regrew fur, recovered kidney function and increased their activity.

The design is unusual and worth understanding. 'D-retro-inverso' means the sequence is reversed and built from mirror-image amino acids. The construction preserves the shape the target recognises while making the molecule nearly invisible to the enzymes that would destroy a normal peptide.

It works by making cells commit suicide. That is the mechanism, stated plainly: it disrupts the FOXO4–p53 interaction that senescent cells depend on, so p53 does what it normally would and triggers apoptosis. Selectivity for senescent cells is what makes that a treatment — not a poison — and that selectivity has been demonstrated in mice and never in a person.

How it works

Senescent cells survive by sequestering p53 in the nucleus through an interaction with FOXO4. p53 would otherwise trigger apoptosis. The cell is being actively prevented from dying.

FOXO4-DRI competes for that interaction, releasing p53 to do what it normally does. The cell dies. Healthy cells, which are not depending on that sequestration, are reported to be unaffected.

The D-retro-inverso construction reverses the peptide sequence and uses mirror-image amino acids. The resulting molecule presents a similar three-dimensional surface while being resistant to the proteases that would clear a conventional peptide within minutes.

Clearing senescent cells is a real and active field, with several small-molecule senolytics in early human trials. This peptide is not among them.

Quick reference

Commonly described dose: 1 mg–5 mg
How often: Every other day for a short course, repeated rarely
Route: Subcutaneous or Intravenous
Where: Abdomen
Timing: No timing effect established.
Storage once mixed: Refrigerated, 28 days
Cycle: A few doses over 1 to 2 weeks on, Months off

These describe what sources report, not what you should do. Full detail and provenance in the dosing section below.

Price index

Per-milligram pricing across vendors arrives with the directory. We are recording prices now so the history exists when the page ships.

Vocabulary on this page

Injection site: Where on the body an injection is given. Rotating between sites is standard practice for anything given repeatedly.
Peptide: A short chain of amino acids: the same building blocks as a protein, in a chain short enough to behave differently.

The whole glossary →

Regulatory status — United States

Not approved anywhere and never studied in a human trial. Other senolytic agents have entered early human trials; this peptide has not. Sold only as a research chemical.

Last reviewed 18 Aug 2026. Regulatory positions in this category change frequently; we date this line so you can see how current it is.

What it is studied for

Each entry states the evidence behind it. We do not rank indications by effectiveness — for most compounds here, that would be a claim nobody can support.

Clearing senescent cells

Published review

What the landmark study demonstrated.

EvidenceIn aged and progeroid mice, treatment restored fur density, kidney function and physical activity. No human trial has been conducted.

Identity and clearance

Molecule

Class: D-retro-inverso peptide targeting the FOXO4–p53 interaction

Built from mirror-image amino acids in reversed order, a construction chosen for protease resistance.

Dose protocols reported in sources

Displayed for reference only. Every row says where it came from, and a trial protocol and a community convention are not the same kind of information. None of this is fed into the calculator, and none of it is a recommendation.

Dose protocols reported in sources, with the source of each.
Goal	Dose	Frequency	Route	Units, 5 mg vial	Source	Start this protocol
Commonly described community protocol	1 mg – 5 mg	Every other day for a short course, repeated rarely	SubcutaneousScaled by guesswork from the mouse study. The intermittent pattern reflects the fact that senolytics are hit-and-run by design: you clear a population of cells and stop. The specific figures still have no human basis.	20–100 u	Community practice	Start this

Start this copies a row into a protocol of your own, which you can then edit. Where a source gave a dose range or an ambiguous frequency, those fields arrive empty — we will not pick a number on your behalf.

CheckRows marked community practice describe what people commonly do, drawn from public discussion. They are not derived from any trial and are not evidence that a dose is safe or effective.

Cycling

Community practice

A few doses over 1 to 2 weeks on, Months off.

Senolytics are intermittent by nature: the target is a population of cells to be cleared, not a signal to be maintained. That logic is sound; the specific schedule is guesswork.

Calculator

Work out what to draw

Pre-filled with a 10 mg vial as a worked example. These are not recommended values — change them to match the vial in front of you.

Draw to 40 units on a 1 mL U-100 syringe. That is 0.4 mL, containing 2 mg of FOXO4-DRI.

Concentration5mg / mL

Volume drawn0.4mL

Doses per vial5doses

Per unit50mcg / unit

40 units sits exactly on a printed line.

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Bioalmanac performs arithmetic on values you enter. It does not recommend doses, schedules or compounds, and nothing here is medical advice. Confirm every calculation against your vial and syringe before drawing, and speak with a licensed healthcare provider.

Open this calculation in the full calculator

Units, concentration, bacteriostatic water — the glossary defines the vocabulary, and a unit is not a fixed volume.

Safety

Reported effects

Everything in humansCommunity practice
Unknown
No human study exists at any dose by any route.
Killing cells that were not the targetPublished review
Mechanistically possible, unquantified in humans
The selectivity depends on senescent cells being the ones sequestering p53. Cell types that use similar survival mechanisms are the obvious concern, and nobody has mapped that in a person.
Consequences of clearing senescent cells rapidlyPublished review
Unknown
Senescent cells are not purely harmful. The same state limits tumour formation and takes part in wound healing. Removing them in bulk has trade-offs the mouse work was not designed to detect.

When to stop

Any acute reaction: fever, breathlessness, chest pain. Seek urgent care.
Any allergic response: rash, hives, facial swelling or difficulty breathing. Seek urgent care.
Any new lump or unexplained persistent symptom.
An injection site that becomes hot, spreading or produces pus.

Interactions and situations that need care

Active or previous cancerAvoid
Cellular senescence is one of the body's brakes on tumour formation. A cell that has stopped dividing cannot become a tumour. Clearing senescent cells deliberately in someone with malignancy removes a brake, and nothing establishes what that does.
Recent surgery or an unhealed woundUse caution
Senescent cells participate in normal wound healing. Clearing them while tissue is repairing is a plausible way to make repair worse, and it has not been studied.
Pregnancy and breastfeedingAvoid
A compound that triggers programmed cell death has no appropriate use during development, and no safety data exists.

What to expect

HonestlyThere is no human efficacy data for this compound, so there is no evidence-based timeline to give. Any site publishing a week-by-week schedule of expected effects has invented it.

The mouse result is genuinely striking, and it is a mouse result from essentially one paper.
No human trial exists. Other senolytics have reached early human trials; this peptide has not.
The mechanism is making cells kill themselves. Selectivity is the entire safety argument, and it has only been shown in mice.
Senescent cells are not purely bad. They also suppress tumours and help wounds heal. Clearing them has trade-offs the mouse work was not built to find.
Dose figures are scaled from mice by guesswork.

Storage and handling

Freeze-dried powder: Refrigerated at 2–8 °C, protected from light.
After mixing: Refrigerated at 2–8 °C. Do not freeze once mixed.
Long-term, frozen: Unopened powder is stable at −20 °C or colder.

Printable one-pager How to reconstitute a vial, step by step

Checking your vial

Research chemicals carry no manufacturing standard, so what the vial looks like is often the only quality signal available before you use it. More on assessing quality and COAs.

White cake, clear solution
Standard for a lyophilised peptide.
Collapsed cake or cloudy solution
Heat damage or degradation. Do not use it.

Questions

What does D-retro-inverso mean?: The sequence is reversed and built from mirror-image amino acids. The resulting molecule presents a similar shape to its target while being nearly invisible to the enzymes that would destroy an ordinary peptide, so it lasts far longer.
Are senolytics a real field?: Yes, and an active one. Several small molecules are in early human trials for age-related conditions. This peptide is not among them, and being part of a legitimate research direction is not the same as being tested.

References

Targeted apoptosis of senescent cells restores tissue homeostasis in response to chemotoxicity and aging
Cell, 2017 · Animal study
Aged, progeroid and chemotherapy-treated mice
Targeted clearance of senescent cells restored fur density, renal function and physical activity in aged mice. A landmark result, and one that has not been followed by any human trial of this peptide.
10.1016/j.cell.2017.02.031
Commonly reported community protocols
Bioalmanac editorial summary of public community sources, 2026 · Not a study
Records dose and route patterns described in public discussion. Carries no evidential weight about safety or effect.

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Keep this page honest

If something here is wrong, out of date, or missing a source, tell us and we will fix it and say that we did.

Suggest a correction

This page is educational. It describes what published research reports, not what you should do. Peptides discussed here are largely not approved for human use, and nothing on Bioalmanac is medical advice. No clinician reviews these pages.

Page last updated 18 Aug 2026