Epithalon vs FOXO4-DRI
A tiny but mighty four-amino-acid peptide that activates your body's telomerase enzyme—essentially helping your cells hit the 'reset' button on aging by protecting and lengthening the protective caps on your chromosomes [1][2].
A senolytic peptide that clears aged "zombie" cells to support healthy aging — run in short, cycled courses a few times a year.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Quick comparison
Dose range
Epithalon
5–10 mg
FOXO4-DRI
1–5 mg
Frequency
Epithalon
Once daily
FOXO4-DRI
Cycled — short courses 2–4 times per year, not daily year-round
Administration
Epithalon
Subcutaneous injection
FOXO4-DRI
Subcutaneous injection
Cycle length
Epithalon
4-6 weeks
FOXO4-DRI
Short "hit-and-run" cycles: either 3 doses over about a week, or a 2-week 5-on/2-off course, repeated every 4–6 months
Onset speed
Epithalon
Gradual (3-4 weeks)
FOXO4-DRI
Works in bursts — senescent-cell clearance starts within days, and benefits build over the following weeks
Evidence level
Epithalon
Limited human trials
FOXO4-DRI
Preclinical only — animal and cell-culture studies; no human trials
Benefit ratings
Telomere Protection
Sleep Quality
Cellular Longevity
Senescent cell clearance
Tissue rejuvenation (animal)
Selectivity for old cells
Healthy-aging support
Compound specifications
Epithalon
Molecular formula
C14H22N4O9
Molecular weight
390.35 g/mol
Half-life
2-4 hours (estimated)
Bioavailability
High when injected subcutaneously
CAS number
307297-39-8
FOXO4-DRI
Molecular formula
C228H388N86O64
Molecular weight
5358 g/mol
Half-life
Not formally established in humans; the D-retro-inverso design resists enzyme breakdown, giving longer stability than ordinary L-peptides
Bioavailability
Not established; animal studies used intraperitoneal injection. Oral bioavailability is not established
CAS number
2460055-10-9
Dosing compared
Epithalon
Sublingual or parabulbar
0.5 mg (sublingual) / 5.0 micrograms per eye (parabulbar)
Once daily · 20 days (sublingual) or 10 days (parabulbar)
Source class: clinical trial protocol. These are the only two human uses of the synthetic tetrapeptide Epitalon identified in a 2025 peer-reviewed review: 5.0 micrograms per eye injected parabulbarly for 10 consecutive days in retinitis pigmentosa, and 0.5 mg per day sublingually for 20 days in a circadian rhythm study [3]. The same review states that toxicity studies needed before approval as an active ingredient have not been done [3].
Subcutaneous
5-10 mg
Once daily · 10-20 day course, repeated 1-3 times per year
Source class: community practice, not peer-reviewed. No published human study has given the synthetic tetrapeptide Epitalon by subcutaneous or intramuscular injection at any dose. This figure is 10 to 20 times the only systemic human dose reported for the synthetic peptide, which is 0.5 mg per day sublingually [3]. It is often attributed to Khavinson's Russian clinical work, but that work used Epithalamin, the pineal gland extract, rather than the synthetic peptide [6][8].
FOXO4-DRI
Best suited for
Epithalon
Longevity Enthusiasts
If you're serious about healthy aging and want to support your cells at the deepest level, Epithalon targets one of the fundamental mechanisms of cellular aging—telomere shortening [1][2]. It's like giving your cells' protective caps a little extra reinforcement.
Sleep Quality Seekers
Epithalon helps regulate melatonin production by supporting your pineal gland [3]. Many users report better sleep quality and more consistent sleep-wake cycles, especially those who've noticed their sleep getting worse with age.
Those Concerned About Oxidative Stress
Beyond its telomere effects, Epithalon acts as an antioxidant [5]. If you're exposed to environmental stressors, have a demanding lifestyle, or simply want extra cellular protection, this peptide offers multiple mechanisms of support.
Immune System Support (Age-Related)
As we age, our immune system naturally weakens—a process called immunosenescence. Research suggests Epithalon may help maintain immune function by supporting the thymus and immune cell health, potentially keeping your defenses stronger as you age [7].
FOXO4-DRI
Senescent ("zombie") cell research
FOXO4-DRI is one of the best-studied tools for selectively clearing senescent cells in the lab. In aged mice and in human cells grown in a dish, it removed these worn-out cells while leaving healthy ones largely alone [1][2].
Healthy-aging and tissue-function research
In its first study, aged mice regained fur density, kidney function, and physical fitness after treatment [1]. Later work showed renewed blood-vessel cell function and less artery stiffness in animals [3]. This makes it a key research compound for understanding how clearing old cells affects whole-body aging.
Mechanism and drug-design research
Because scientists have mapped exactly where it binds p53 [5], FOXO4-DRI is valuable for studying the FOXO4–p53 survival pathway and for designing future senolytic drugs.
Side effects
Epithalon
Common
- Injection site redness
- Mild headache
- Temporary fatigue
Uncommon
- Vivid dreams
- Sleep pattern changes
Serious
- Allergic reaction
FOXO4-DRI
Common
- Temporary tiredness during a cycle
Uncommon
- Injection-site reactions
Serious
- Cancer-pathway caution and allergic reactions
Safety & evidence
Epithalon
Evidence level
Limited human trials
FDA status
Research compound
Safety overview
Two different substances share this page's name, and almost all of the human data belongs to the older one. Epithalamin is an extract of the pineal gland. Epitalon (also written Epithalon, sequence Ala-Glu-Asp-Gly) is the synthetic four-amino-acid peptide later identified within it [4]. The long-term human studies people cite for this compound used **Epithalamin, the extract** — not the synthetic peptide. Those studies report the outcomes plainly. In 266 elderly people followed 6-8 years, mortality in the Epithalamin group fell 1.6-1.8-fold against control [6]. In a separate 12-year randomised study in elderly patients with coronary disease, deaths in the epithalamine group were 28% lower than control on the same basic therapy, and cardiovascular mortality was 2-fold lower [8]. For the synthetic peptide itself, a 2025 peer-reviewed review identifies only two human uses: 5.0 micrograms per eye injected parabulbarly for 10 consecutive days in retinitis pigmentosa, and 0.5 mg per day sublingually for 20 days in a circadian rhythm study [3]. That same review states that before Epitalon could be approved as a new active ingredient, further studies of short- and long-term toxicity are essential, including genotoxicity, carcinogenic potential and food-drug interactions [3]. Reported side effects across this literature are limited to mild injection site reactions. Nearly all of it comes from one research group in Russia [3][6].
Contraindications
- Pregnancy or planning to become pregnant
- Currently breastfeeding
- Active cancer or history of cancer
- Known allergy to peptide components
- Children and adolescents
FOXO4-DRI
Evidence level
Preclinical only — animal and cell-culture studies; no human trials
FDA status
Research compound (not approved for human use)
Safety overview
FOXO4-DRI is generally run in short, spaced-out cycles, which keeps exposure low. The most common experiences are mild and short-lived: some tiredness or a flu-like feeling for a day or two during a cycle as your body clears dead cells, plus the usual minor injection-site soreness. The one real precaution worth taking seriously: because it activates p53, the protein that guards against cancer, anyone with active or recent cancer should only use it under an oncologist's care. If you are pregnant, breastfeeding, or under 18, skip it.
Contraindications
- No established human safety profile — any human use is experimental
- Active or recent cancer (the p53 pathway it acts on is not characterized for this use in humans)
- Pregnancy and breastfeeding
- Children and adolescents
Which is right for you?
Choose Epithalon if...
- Longevity and healthy aging
- Cellular rejuvenation
- Sleep quality improvement
- Antioxidant support
Choose FOXO4-DRI if...
- Senescent cell clearance research
- Healthy-aging and longevity research
- Laboratory and preclinical study