MEDICAL DISCLAIMER: Educational research guidelines only. Lyophilized peptides are investigational chemical compounds and are NOT approved for human consumption, diagnosis, or therapy. Consult a licensed physician before any research application.
FOXO4-DRI Dosage Chart, Schedule & Reconstitution Protocol
Quickstart Highlights
FOXO4-DRI is a D-retro-inverso senolytic peptide designed by Baar, Brandt, Putavet and colleagues in the Peter de Keizer laboratory at Erasmus University, published in Cell in 2017 (PMID: 28340339). The sequence is derived from the FOXO4 transcription factor's interaction interface with p53 but synthesized entirely from D-amino acids in reverse order, producing a protease-resistant compound that disrupts the FOXO4-p53 complex inside senescent cells. By freeing nuclear p53, FOXO4-DRI triggers apoptosis selectively in cells with the senescence-associated secretory phenotype while sparing healthy proliferating cells. In aged and fast-aging Xpd-deficient mice, intermittent FOXO4-DRI dosing restored fitness, fur density, and renal function. Researchers study it as a prototype senolytic, a tool compound for senescent-cell biology, and a model for D-retro-inverso peptide design in the broader longevity field.
Reconstitute: Add 3 mL bacteriostatic water → 3.33 mg/mL concentration.
Easy measuring: At 3.33 mg/mL, 1 unit = 0.01 mL = 0.0333 mg (33 mcg) on a U-100 insulin syringe.
Storage: Lyophilized frozen at −20 °C; reconstituted refrigerated at 2–8 °C; avoid repeated freeze–thaw[8].
Half-life: The all-D retro-inverso architecture confers resistance to most proteases, extending plasma exposure substantially beyond an L-amino acid peptide of the same sequence; precise human PK data are not published.
Route: Intraperitoneal injection in the original mouse studies; subcutaneous and intravenous routes appear in subsequent preclinical work. No validated human delivery route has been published.
Status: Investigational research peptide only; not FDA, EMA, or MHRA approved. No registered human clinical trials have read out, and all efficacy data come from rodent senolytic experiments.
Quick Protocol Navigation
Reconstitution Instruction & Mixing Step-by-Step
Lyophilized powder must be reconstituted carefully. Agitating peptide chains can shear disulfide bonds and render the peptide biologically inert.
Draw 3.0 mL bacteriostatic water with a sterile syringe.
Inject slowly down the vial wall; avoid foaming.
Gently swirl/roll until dissolved (do not shake)[8].
Inject slowly and steadily; no need to aspirate for subcutaneous injections[11].
Do not aspirate for subcutaneous injections; inject slowly and steadily[11].
Interactive FOXO4-DRI Syringe Calculator
Currently visualizing the 10 mg vial reconstituted with 3 mL bacteriostatic water. Adjust the target dose to dynamically render syringe units.
Reconstitution Calculation: 10mg dry powder in 3mL water yields 3.33 mg/mL. To evaluate a 250mcg dose, pull to 7.5 units (8 syringe ticks).
U-100 Syringe Representation
7.5 Units (8 Ticks)
Educational reference visual. Assumes standard U-100 insulin syringe where 1.0 mL volume = 100 units.
Titration & Dose Escalation Schedules
| Week | Daily Dose (mcg) | Units (per injection) (mL) |
|---|---|---|
| Weeks 1–4 | 250 mcg | 7.5 units (0.075 mL) |
| Weeks 5–8 | 375 mcg | 11 units (0.11 mL) |
| Weeks 9–12 | 500 mcg | 15 units (0.15 mL) |
| Weeks 13–16 | 500 mcg | 15 units (0.15 mL) |
Administration guidelines: Refer to guidelines | 3 mL Reconstitution
Research Supplies Quantity Planner
Scientific mathematical planning of syringes, bacteriostatic water and dry vials needed for extended research blocks using the 10 mg vial.
Peptide Vials (FOXO4-DRI, 10 mg each):
- check8 weeks ≈ 3 vials
- check12 weeks ≈ 4 vials
- check16 weeks ≈ 5 vials
Insulin Syringes (U-100):
- checkPer week: 7 syringes (1/day)
- check8 weeks: 56 syringes
- check12 weeks: 84 syringes
- check16 weeks: 112 syringes
Bacteriostatic Water (10 mL bottles): Use ~3.0 mL per vial for reconstitution.
- check8 weeks (3 vials): 9 mL → 1 × 10 mL bottle
- check12 weeks (4 vials): 12 mL → 2 × 10 mL bottles
- check16 weeks (5 vials): 15 mL → 2 × 10 mL bottles
Alcohol Swabs: One for the vial stopper + one for the injection site each day.
- checkPer week: 14 swabs (2/day)
- check8 weeks: 112 swabs → recommend 2 × 100-count boxes
- check12 weeks: 168 swabs → recommend 2 × 100-count boxes
- check16 weeks: 224 swabs → recommend 3 × 100-count boxes
Mechanism of Action (MOA)
Cellular senescence is a state of stable cell-cycle arrest accompanied by a pro-inflammatory senescence-associated secretory phenotype (SASP) that contributes to tissue dysfunction and age-related disease. Senescent cells normally resist apoptosis because they upregulate anti-apoptotic networks; in particular, the forkhead transcription factor FOXO4 binds and sequesters p53 in the nucleus, preventing p53 from translocating to mitochondria and triggering the intrinsic apoptosis pathway. Baar, de Keizer, and colleagues at the Erasmus Medical Center designed FOXO4-DRI as a competitive disruptor of this FOXO4-p53 interaction: the peptide corresponds to the FOXO4 region that binds p53, engineered with D-amino acids in reversed sequence to preserve the binding conformation while resisting proteolysis [1]. By binding the p53 transactivation domain, FOXO4-DRI displaces endogenous FOXO4, releasing p53 to translocate to mitochondria and initiate apoptosis selectively in senescent cells where this pathway is otherwise blocked. Healthy non-senescent cells, which do not depend on FOXO4-p53 sequestration to control apoptosis, are largely unaffected. The D-retro-inverso modification is biochemically significant: D-amino acids are not substrates for endogenous proteases, so FOXO4-DRI half-life in vivo is dramatically longer than native L-peptides of similar length, allowing reasonable systemic exposure after intraperitoneal or intravenous administration. The 2017 Cell paper showed that FOXO4-DRI selectively killed senescent IMR90 fibroblasts and irradiated cancer cells in vitro while sparing non-senescent populations [1]. In rapidly aging XpdTTD/TTD mice and naturally aged mice, intraperitoneal FOXO4-DRI at 5 mg/kg three times weekly restored fur density, renal function (reduced blood urea nitrogen), and physical fitness (running wheel performance), with concurrent reductions in senescent cell burden in kidney and other tissues. Subsequent work by de Keizer's group and others has extended the senolytic concept: Bigot et al. showed FOXO4-DRI selectively removes senescent cells from in vitro expanded human chondrocytes, supporting potential applications in osteoarthritis [4]. A 2024 mechanistic study confirmed that the disordered p53 transactivation domain is the binding target of FOXO4 and FOXO4-DRI, providing structural validation of the design hypothesis [5]. A 2025 endothelial study demonstrated FOXO4-DRI regulation of endothelial cell senescence via the p53 pathway, supporting cardiovascular applications [6]. Pharmacokinetically, FOXO4-DRI is a relatively large peptide (approximately 5 kDa) and is administered parenterally; intraperitoneal delivery is standard in rodent studies and intravenous infusion is the most likely human route. Oral bioavailability is essentially zero. Plasma half-life in mice is several hours owing to D-amino acid stabilization. Human pharmacokinetic data are absent, and there are no published human clinical trials. The gap between rodent dosing (5 mg/kg three times weekly for several weeks) and what some research-community users self-administer is enormous, raising significant safety concerns about extrapolation from animal models to human use.
Clinical Trial Efficacy Highlights
- starBaar, de Keizer, and colleagues showed in Cell 2017 that FOXO4-DRI selectively killed senescent IMR90 fibroblasts and irradiated cancer cells in vitro at concentrations 10–30 fold lower than required to affect non-senescent cells, demonstrating the first peptide-based senolytic with selective activity [1].
- starIn rapidly aging XpdTTD/TTD mice, intraperitoneal FOXO4-DRI at 5 mg/kg three times weekly restored fur density, body condition, and running-wheel performance over 3 weeks of treatment, with reductions in senescent cell markers in kidney and other tissues [1].
- starIn naturally aged 24-month-old C57BL/6 mice, FOXO4-DRI improved renal function (reduced blood urea nitrogen and creatinine) and restored physical fitness, with concurrent reductions in p21+ senescent cells in kidney sections [1].
- starBigot and colleagues demonstrated that FOXO4-DRI selectively removes senescent cells from in vitro expanded human chondrocytes, supporting potential applications in osteoarthritis and cartilage regeneration [4].
- starA 2024 PMC mechanistic study using NMR and isothermal titration calorimetry confirmed that the disordered p53 transactivation domain is the binding target of FOXO4 and FOXO4-DRI, validating the design hypothesis at the structural level [5].
- starA 2025 endothelial cell study showed FOXO4-DRI regulates endothelial cell senescence via the p53 signaling pathway, with reductions in senescence-associated beta-galactosidase staining and SASP cytokines in stressed endothelial cultures [6].
- starFOXO4-DRI has been tested in cancer cell models showing selective elimination of chemotherapy-induced senescent cancer cells, supporting potential adjunct use in oncology to clear therapy-induced senescent tumor cells [7].
- starNo published human clinical trials of FOXO4-DRI exist; all efficacy claims rest on mouse and cell-culture data, and translation to human senolytic therapy is unproven. The gap between rodent doses and self-administered human doses raises significant safety questions.
Side Effects & Tolerability Profile
Clinical subjects transiently report mild side effects. Slowly escalating the titration dose represents the single most effective intervention to limit side effects.
- warningFOXO4-DRI has no documented human safety data; no controlled human pharmacokinetic, pharmacodynamic, or adverse-event studies have been published.
- warningIn mice, transient increases in liver enzymes and mild renal stress markers have been observed at therapeutic doses, generally resolving after course completion.
- warningTheoretical risks include excessive apoptosis if non-senescent cells are inadvertently targeted, particularly in tissues with high cell turnover; the selectivity margin in clinical populations is unknown.
- warningInflammatory flare from sudden senescent cell clearance (analogous to cytokine release syndromes seen with other senolytics) is a theoretical concern, especially in patients with high senescent cell burden.
- warningInjection-site reactions with subcutaneous or intraperitoneal administration are expected; the peptide is delivered parenterally and is not orally bioavailable.
- warningDrug-drug interaction data are absent; concurrent use with chemotherapy or other senolytics is uncharacterized and theoretically additive.
- warningReproductive, pregnancy, and lactation safety are entirely unstudied and FOXO4-DRI should not be used in these populations.
- warningAnecdotal reports from research-chemical users include flu-like symptoms, malaise, and fatigue lasting 1–3 days after dosing, possibly reflecting cytokine release from senescent cell clearance, but these reports are uncontrolled.
Subcutaneous Injection Technique
Most research peptides require subcutaneous injection into fatty tissue. Never inject directly into a blood vessel or deep muscle tissue unless clinically detailed.
1. Site Selection
Common locations include the abdomen (2 inches from navel), outer upper arms, or thighs.
2. Sanitization
Thoroughly clean the selected site, stopper and vial top using 70% isopropyl alcohol prep swabs.
3. Angle & Push
Pinch the skin and insert the needle at a 45 to 90-degree angle. Depress plunger smoothly.
4. Site Rotation
Rotate injection sites continuously to avoid lipodystrophy or tissue scarring.
Frequently Asked Questions
What is the typical FOXO4-DRI dosage?expand_more
There is no validated human dose. The original mouse studies used 5 mg/kg intraperitoneally three times weekly for 3 weeks. Human equivalent doses by allometric scaling would be approximately 0.4 mg/kg, but no clinical trials have validated this and self-administered research-community doses vary widely.
How is FOXO4-DRI administered?expand_more
FOXO4-DRI is administered parenterally — intraperitoneal injection in rodent studies, with intravenous infusion or subcutaneous injection as the most likely human routes. Oral bioavailability is essentially zero due to peptide size and absence of dedicated transporters.
Can FOXO4-DRI be stacked?expand_more
Combination with other senolytics (dasatinib + quercetin, fisetin) is theoretically additive on senescent cell clearance and is described in research-community use. The clinical safety and efficacy of such combinations is entirely uncharacterized in controlled human studies.
What are the side effects of FOXO4-DRI?expand_more
Human safety data are absent. Anecdotal reports include flu-like symptoms, fatigue, and malaise after dosing, possibly reflecting senescent cell clearance. Theoretical risks include off-target apoptosis, inflammatory flare, and injection-site reactions. Controlled adverse-event surveillance does not exist.
Is FOXO4-DRI FDA approved?expand_more
No. FOXO4-DRI has no regulatory approval anywhere in the world and is not registered as a pharmaceutical. It remains a research-only compound with no published human clinical trials and is sold strictly for in vitro and preclinical investigation.
Academic References & Study Citations
Baar MP, Brandt RMC, Putavet DA, et al. Targeted apoptosis of senescent cells restores tissue homeostasis in response to chemotoxicity and aging. Cell. 2017;169(1):132-147.e16. View Scientific Paper →
de Keizer PLJ. The fountain of youth by targeting senescent cells? Trends Mol Med. 2017;23(1):6-17. View Scientific Paper →
Boon RA, Iekushi K, Lechner S, et al. MicroRNA-34a regulates cardiac ageing and function. Nature. 2013;495(7439):107-10. View Scientific Paper →
Bigot N, Loïc Le M, Trichet V, et al. Senolytic peptide FOXO4-DRI selectively removes senescent cells from in vitro expanded human chondrocytes. Front Bioeng Biotechnol. 2020;8:582353. View Scientific Paper →
Development of a novel senolytic by precise disruption of FOXO4-p53 complex. PMC. 2021. View Scientific Paper →
FOXO4-DRI regulates endothelial cell senescence via the P53 signaling pathway. PMC. 2025. View Scientific Paper →
The disordered p53 transactivation domain is the target of FOXO4 and the senolytic compound FOXO4-DRI. PMC. 2024. View Scientific Paper →
van Vliet T, Varela-Eirin M, Wang B, et al. Physiological hypoxia restrains the senescence-associated secretory phenotype via AMPK-mediated mTOR suppression. Mol Cell. 2021;81(9):2041-2052. View Scientific Paper →
Childs BG, Gluscevic M, Baker DJ, et al. Senescent cells: an emerging target for diseases of ageing. Nat Rev Drug Discov. 2017;16(10):718-735. View Scientific Paper →
Kirkland JL, Tchkonia T. Senolytic drugs: from discovery to translation. J Intern Med. 2020;288(5):518-536. View Scientific Paper →