Epithalon vs P-21 Peptide
A neutral, side-by-side comparison of two anti-aging & longevity peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
Epithalon
Epithalon is a synthetic tetrapeptide (Ala-Glu-Asp-Gly) derived from Epithalamin, a polypeptide extract of the pineal gland. It has been studied since the 1980s by Russian researchers, primarily Vladimir Khavinson, for its ability to activate telomerase and extend telomere length — one of the few compounds with direct evidence of telomere elongation in human cells.
Full profileP-21 Peptide
Short neuropeptide based on the activity-dependent neurotrophic factor (ADNF) family with potent neuroprotective effects demonstrated in Alzheimer's disease models. Distinct from the cell cycle inhibitor protein p21/CDKN1A. Reduces amyloid-beta burden, improves cognitive outcomes in rodent models, and modulates neuroinflammation through STAT3 and JAK2 signaling pathways.
Full profile| Epithalon | P-21 Peptide | |
|---|---|---|
| Category | Anti-Aging & Longevity | Anti-Aging & Longevity |
| Also known as | Epitalon, Epithalone, Tetrapeptide Ala-Glu-Asp-Gly | P21, Colivelin fragment, P21 neuropeptide, ADNF-related neuropeptide |
| Evidence | Research-stage | Preclinical only |
| Dosing range | 5mg–20mg mg, daily for 10–20 day cycles, 1–2x per year | 5mcg–20mcg mcg, daily or every other day (intranasal or SC) |
| Administration | Subcutaneous injection, Intravenous (clinical studies), Intranasal | Intranasal, Subcutaneous injection |
| Key side effects | Generally very well-tolerated, Injection site discomfort, Vivid dreams (commonly reported), Improved sleep depth (often reported as benefit) | Limited human safety data, In animal studies: well-tolerated at therapeutic doses, Theoretical STAT3 pathway concerns with chronic use (pro-survival signaling), Nasal irritation (intranasal route) |
| Cited sources | 2 references | 2 references |
Key differences
- Evidence level differs: Epithalon is research-stage, while P-21 Peptide is preclinical only.
- Administration: Epithalon — Subcutaneous injection, Intravenous (clinical studies), Intranasal; P-21 Peptide — Intranasal, Subcutaneous injection.
- Dosing units differ: Epithalon is dosed in mg, P-21 Peptide in mcg — they operate at different scales.
- Frequency: Epithalon is typically daily for 10–20 day cycles, 1–2x per year; P-21 Peptide is daily or every other day (intranasal or SC).
How each works
Epithalon
Epithalon activates telomerase (hTERT), the enzyme responsible for maintaining telomere length. In vitro and animal studies show telomere elongation, extended cell lifespan, and reduced DNA oxidation. Russian clinical studies in aging populations report improved melatonin rhythms, immune function, and reduced cancer incidence over multi-year follow-up.
P-21 Peptide
P-21 activates STAT3/JAK2 signaling through CNTF-related pathways, reducing amyloid-beta toxicity by activating amyloid-clearing enzymes (insulin-degrading enzyme, neprilysin) and inhibiting tau phosphorylation. Derived from the colivelin family of neuroprotective peptides, P-21 demonstrates cognitive improvement in Alzheimer's mouse models at doses far below cytotoxic levels. Human data remains limited.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.