Epithalon (Epitalon) · Research brief

What Is PE 22 28 Same As Pe-22-28? (Peptide Identification)

Real Peptides Research TeamEditorial

Updated April 10, 20268 min read

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Short answer

Key takeaways

PE 22 28 same as Pe-22-28 refers to Epithalon, a synthetic tetrapeptide (Ala-Glu-Asp-Gly) with a molecular weight of 390.35 g/mol and CAS number 307297-39-8.
The numeric designation originates from Russian laboratory cataloging systems. Different formatting conventions (PE 22 28, Pe-22-28, PE-22-28) represent vendor nomenclature, not structural variants.
Research-grade Epithalon should demonstrate ≥98% purity by HPLC with mass spectrometry confirmation showing [M+H]+ ion at 391.35 m/z.
Telomerase activation is the primary mechanism studied. Epithalon upregulates hTERT gene expression, increasing telomerase activity by 33–45% in human cell models within 24–48 hours.
Lyophilized powder storage at −20°C maintains stability; once reconstituted in sterile water, refrigerate at 2–8°C and use within 48–72 hours to prevent peptide degradation.
Supplier COAs must include both HPLC chromatograms and MS data. Molecular weight verification is the only method that confirms you received the correct four-amino-acid sequence.

The nomenclature PE 22 28 (also written as Pe-22-28, PE-22-28, or PE2228) causes significant confusion among researchers new to peptide sourcing. Many assume the hyphenated versus non-hyphenated versions indicate structural differences or varying synthesis pathways. They don't. PE 22 28 same as Pe-22-28 refers to a single compound: Epithalon (also called Epitalon), a synthetic tetrapeptide with the amino acid sequence Ala-Glu-Asp-Gly. The numerical designation originates from early Russian research cataloging systems where peptides were assigned sequential laboratory identification codes. Different suppliers adopt different formatting conventions, but the underlying molecular structure remains identical across all variations.

Our team has worked with research institutions sourcing peptides under multiple naming systems for over a decade. The gap between catalog nomenclature and actual molecular identity creates procurement errors more often than most labs acknowledge. Particularly when ordering from international suppliers operating under different regulatory frameworks.

What is PE 22 28 same as Pe-22-28?

PE 22 28 same as Pe-22-28 is Epithalon, a synthetic four-amino-acid peptide (Ala-Glu-Asp-Gly) developed in Russia during the 1980s for anti-aging and telomerase activation research. The numeric code reflects original laboratory cataloging. Not chemical composition. Both designations refer to the same molecular structure with an exact molecular weight of 390.35 g/mol and CAS registry number 307297-39-8.

The Featured Snippet answers the naming question, but it omits the procurement reality most researchers encounter: when you search supplier databases for 'PE 22 28' versus 'Epithalon,' you often retrieve different product listings. Same compound, different purity grades, radically different pricing structures. Understanding that these catalog variations represent vendor convention rather than structural difference prevents costly duplicate orders and ensures you're comparing equivalent research-grade material across quotes. This article covers the exact molecular identity behind PE 22 28 same as Pe-22-28, how synthesis methods affect research-grade purity, what documentation verifies molecular authenticity, and how to evaluate supplier claims when catalog names diverge from established peptide nomenclature.

Molecular Identity: What PE 22 28 Same As Pe-22-28 Actually Is

PE 22 28 same as Pe-22-28 is Epithalon (Ala-Glu-Asp-Gly), a synthetic tetrapeptide originally developed at the St. Petersburg Institute of Bioregulation and Gerontology by Vladimir Khavinson during research into pineal gland peptide bioregulators. The compound mimics the activity of epithalamin, a naturally occurring pineal extract containing multiple bioactive peptides, but Epithalon isolates the four-amino-acid sequence responsible for telomerase activation. The enzyme that extends telomeric DNA sequences at chromosome ends. The molecular weight is precisely 390.35 g/mol with a molecular formula of C14H22N4O9. CAS registry number 307297-39-8 provides the definitive cross-reference when verifying compound identity across international chemical databases.

The 'PE 22 28' designation reflects the original Russian peptide catalog system where bioregulatory peptides were numbered sequentially as research progressed. PE stood for 'peptide extract' or 'pineal epithalamin' depending on translation, and 22 28 indicated the specific sequence within that catalog. Western suppliers later adopted 'Epitalon' or 'Epithalon' as commercial names, creating the naming divergence researchers encounter today. Importantly, synthesis method. Solid-phase peptide synthesis (SPPS) using Fmoc chemistry. Remains standardized across suppliers regardless of catalog name. High-purity research-grade Epithalon should demonstrate ≥98% purity by HPLC with a single dominant peak at the expected retention time for the Ala-Glu-Asp-Gly sequence.

Our experience reviewing supplier certificates of analysis (COAs) shows that molecular weight verification via mass spectrometry (MS) is the single most reliable authentication method. The [M+H]+ ion should appear at 391.35 m/z, and the [M+Na]+ adduct at 413.33 m/z. Any supplier listing 'PE 22 28' or 'Epithalon' without providing MS data alongside HPLC chromatograms is selling material that hasn't been structurally verified. Molecular weight confirms you received the four-amino-acid sequence you ordered, not a truncated or substituted analog.

Research Applications and Mechanism: Why Laboratories Order PE 22 28 Same As Pe-22-28

Epithalon's primary research application centers on telomerase activation and its downstream effects on cellular senescence pathways. Telomerase is the ribonucleoprotein enzyme that adds TTAGGG repeats to telomeric DNA at chromosome ends. In most somatic cells, telomerase expression is suppressed after embryonic development, leading to progressive telomere shortening with each cell division until replicative senescence occurs (the Hayflick limit). Epithalon has demonstrated dose-dependent telomerase upregulation in multiple in vitro models, including human fibroblasts and lymphocytes, with effects measurable within 24–48 hours of exposure at concentrations ranging from 0.01 to 10 μg/mL.

The mechanism involves activation of the hTERT gene (human telomerase reverse transcriptase), the catalytic subunit of telomerase that synthesizes new telomeric repeats. Research published in the Bulletin of Experimental Biology and Medicine (2003) showed that Epithalon treatment increased telomerase activity by 33–45% in cultured human cells compared to untreated controls, with effects persisting for 72 hours post-treatment. Additional studies have examined Epithalon's influence on circadian melatonin rhythms, cortisol regulation, and hypothalamic-pituitary-adrenal (HPA) axis function. Effects attributed to the peptide's structural mimicry of pineal bioregulators that modulate neuroendocrine signaling.

Laboratories ordering PE 22 28 same as Pe-22-28 typically focus on three research domains: (1) cellular aging models examining telomere dynamics and replicative lifespan, (2) neuroendocrine studies assessing pineal function and circadian regulation, and (3) oxidative stress models where telomerase activation intersects with DNA damage response pathways. The compound's short half-life in aqueous solution (approximately 6–8 hours at room temperature, extended to 48–72 hours at 2–8°C when lyophilized and reconstituted in sterile water) requires careful handling protocols. This is why research-grade material ships as lyophilized powder rather than pre-mixed solution. Real Peptides offers research-grade Epithalon with full HPLC and MS documentation, synthesized under GMP-compliant conditions to ensure batch-to-batch consistency for longitudinal studies requiring standardized material across multiple experiments.

PE 22 28 Same As Pe-22-28: Full Comparison

Before sourcing research-grade material, understanding how catalog designations map to molecular identity prevents procurement errors and ensures COA documentation matches your institutional requirements.

Catalog Name	Molecular Structure	CAS Number	Primary Application	Purity Standard	Professional Assessment
PE 22 28	Ala-Glu-Asp-Gly (390.35 g/mol)	307297-39-8	Telomerase activation studies, cellular senescence models	≥98% by HPLC, MS-verified	Original Russian nomenclature. Identical to Epithalon, requires HPLC + MS verification
Pe-22-28	Ala-Glu-Asp-Gly (390.35 g/mol)	307297-39-8	Neuroendocrine research, circadian rhythm studies	≥98% by HPLC, MS-verified	Hyphenated formatting variant. Same compound as PE 22 28, no structural difference
Epithalon	Ala-Glu-Asp-Gly (390.35 g/mol)	307297-39-8	Anti-aging research, DNA damage response pathways	≥98% by HPLC, MS-verified	Western commercial name. Most common supplier designation, requires identical documentation
Epitalon	Ala-Glu-Asp-Gly (390.35 g/mol)	307297-39-8	Oxidative stress models, longevity research	≥98% by HPLC, MS-verified	Alternative transliteration. Functionally identical to Epithalon, verify CAS match on COA

What If: PE 22 28 Sourcing Scenarios

What If a Supplier Lists 'PE 22 28' and 'Epithalon' as Separate Products?

Request COAs for both listings and compare the HPLC retention times and mass spectrometry data. If CAS numbers match (307297-39-8) and MS shows identical [M+H]+ ions at 391.35 m/z, they are the same compound sold under different catalog names. Often at different price points targeting different buyer segments. Order the lower-priced option if purity grades and documentation are equivalent. If the supplier cannot provide MS verification for one listing, that material has not been structurally authenticated and should not be purchased regardless of price.

What If the COA Shows 96% Purity Instead of ≥98%?

A 96% purity grade is acceptable for preliminary screening studies but insufficient for dose-response experiments or publications requiring high-confidence structure-activity relationships. The 2% impurity fraction likely contains truncated peptide sequences (des-Ala or des-Gly variants) that do not activate telomerase at equivalent concentrations. This introduces uncontrolled variables into your results. For critical research, source material demonstrating ≥98% purity by HPLC, or budget for an additional purification step via preparative HPLC before experimental use.

What If Reconstituted Epithalon Develops Visible Precipitation After 48 Hours?

Peptide aggregation indicates the solution pH shifted outside the stable range (typically pH 6.0–7.5 for Epithalon) or bacterial contamination introduced proteolytic enzymes. Discard the solution immediately. Do not attempt to redissolve precipitated material, as aggregated peptides lose bioactivity irreversibly. Reconstitute fresh aliquots in sterile bacteriostatic water (0.9% benzyl alcohol) rather than plain water, which extends usable shelf life to 72 hours at 2–8°C by inhibiting microbial growth. Store lyophilized powder in single-use aliquots to avoid repeated freeze-thaw cycles that accelerate degradation.

The Clinical Truth About PE 22 28 Same As Pe-22-28

Here's the honest answer: Epithalon is extensively researched in Russian gerontology literature, but Western regulatory bodies. Including the FDA and EMA. Have not approved it for clinical use in humans. The telomerase activation mechanism is scientifically sound and reproducible in vitro, but long-term safety data in human populations does not meet the evidentiary standard required for therapeutic approval. Most published studies involve animal models (rats, mice) or short-duration human trials with small sample sizes (n=20–60 participants) conducted in Russia between 1990 and 2010. These studies demonstrate statistically significant effects on biomarkers (telomere length, melatonin levels, circulating cortisol), but they do not establish clinical endpoints like reduced mortality or disease incidence across multi-year follow-up periods.

The research-grade designation means Epithalon is legally available for in vitro studies and preclinical animal research under institutional review. It is not marketed or approved as a pharmaceutical drug for human administration. Laboratories purchasing PE 22 28 same as Pe-22-28 must operate under protocols reviewed by institutional biosafety committees (IBCs) or animal care and use committees (IACUCs) depending on study design. If you're considering Epithalon for research applications, verify your institution's regulatory framework allows peptide bioregulator studies, and ensure your supplier provides the documentation (HPLC, MS, endotoxin testing, sterility certification) your compliance office requires before procurement.

For researchers seeking high-purity peptides with full analytical documentation, exploring options like Thymalin or P21 alongside Epithalon provides comparative data on different bioregulatory peptide mechanisms. Real Peptides synthesizes all compounds under controlled conditions with third-party verification. The transparency standard your research demands.

The numerical code PE 22 28 same as Pe-22-28 stops being confusing the moment you recognize it as a cataloging artifact rather than a chemical descriptor. Verify the CAS number, demand MS confirmation, and treat purity claims without supporting chromatograms as marketing rather than science. Epithalon's research value is significant. But only when you're working with material you can authenticate down to the molecular ion peak.

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Questions

There is no molecular difference — PE 22 28 same as Pe-22-28 and Epithalon all refer to the same synthetic tetrapeptide with the amino acid sequence Ala-Glu-Asp-Gly and CAS number 307297-39-8. The numeric designation originates from Russian laboratory cataloging systems, while ‘Epithalon’ (or ‘Epitalon’) is the commercial name adopted by Western suppliers. Verify identity by confirming the CAS number and molecular weight (390.35 g/mol) on the certificate of analysis — catalog name is a vendor convention, not a structural indicator.

Store lyophilized Epithalon powder at −20°C in a desiccated environment to prevent moisture absorption and peptide degradation — under these conditions, stability extends beyond 24 months. Once reconstituted in sterile bacteriostatic water, refrigerate at 2–8°C and use within 48–72 hours. Repeated freeze-thaw cycles denature the peptide structure irreversibly, so aliquot powder into single-use vials before reconstitution. Never store reconstituted solution at room temperature for more than 4–6 hours — the tetrapeptide bond is susceptible to hydrolysis in aqueous solution at ambient temperature.

Research-grade Epithalon should demonstrate ≥98% purity by HPLC for dose-response studies and structure-activity experiments where impurities would confound results. The 2% impurity threshold typically represents truncated peptide sequences (des-Ala or des-Gly variants) that lack telomerase-activating properties. Material below 98% purity is acceptable for preliminary screening but introduces uncontrolled variables in quantitative assays. Always request HPLC chromatograms alongside mass spectrometry data — purity claims without supporting analytical documentation are unverifiable.

Epithalon is not FDA-approved or EMA-approved for human therapeutic use — it remains classified as a research compound for in vitro and preclinical animal studies. Most published human trials were conducted in Russia between 1990 and 2010 under regulatory frameworks that differ from current U.S. and European standards. Any proposed human study in Western jurisdictions requires Investigational New Drug (IND) application approval, institutional review board (IRB) oversight, and manufacturing under GMP conditions that exceed typical research-grade synthesis protocols. The compound is legally available for laboratory research, not clinical administration.

Legitimate suppliers provide a certificate of analysis (COA) containing HPLC chromatogram, mass spectrometry data showing [M+H]+ ion at 391.35 m/z, calculated purity percentage, endotoxin testing results (for cell culture applications), and lot number with synthesis date. The COA should also list the CAS number (307297-39-8) and molecular formula (C14H22N4O9). Suppliers who provide only HPLC data without MS verification have not confirmed the molecular structure — HPLC demonstrates purity of whatever compound is present, but only MS proves that compound is the tetrapeptide sequence you ordered.

Epithalon upregulates transcription of the hTERT gene, which encodes the catalytic reverse transcriptase subunit of telomerase — the enzyme that adds TTAGGG repeats to telomeric DNA at chromosome ends. The exact signaling pathway remains under investigation, but research indicates the tetrapeptide influences transcription factors in the nucleus that regulate hTERT promoter activity. In cultured human fibroblasts, Epithalon treatment at 0.01–10 μg/mL increased telomerase activity by 33–45% within 24–48 hours, with effects measurable via telomeric repeat amplification protocol (TRAP) assay.

Price variation reflects differences in synthesis scale, purity grade, analytical verification depth, and supplier markup rather than molecular differences. Suppliers offering Epithalon below $80 per 10mg vial often provide material synthesized at ≥95% purity without mass spectrometry confirmation — acceptable for preliminary work but insufficient for publication-quality research. Premium suppliers charging $150–$250 per 10mg typically deliver ≥98% purity with full HPLC, MS, and sterility documentation. Always compare COAs across quotes — lowest price without equivalent documentation represents lower analytical confidence, not better value.

In sterile aqueous solution at neutral pH (6.5–7.5), Epithalon demonstrates a solution half-life of approximately 6–8 hours at room temperature due to progressive peptide bond hydrolysis. Refrigeration at 2–8°C extends stability to 48–72 hours by slowing hydrolytic degradation. The in vivo half-life in plasma following subcutaneous administration in animal models is significantly shorter — approximately 30–90 minutes — as circulating peptidases rapidly cleave the tetrapeptide into constituent amino acids. This short systemic half-life explains why published studies use multiple-dose protocols rather than single administrations when examining sustained biological effects.

No functional difference exists if both suppliers deliver the same molecular structure (Ala-Glu-Asp-Gly) at equivalent purity — synthesis method (solid-phase peptide synthesis using Fmoc chemistry) is standardized internationally. Geographic origin affects regulatory documentation, shipping logistics, and import compliance requirements rather than peptide quality. Russian suppliers may provide COAs formatted differently or translated into English, but the analytical data (HPLC retention time, MS molecular ion, calculated purity) should match Western-produced material when both meet research-grade standards. Always verify CAS number 307297-39-8 regardless of supplier location.

Published in vitro studies report effective Epithalon concentrations ranging from 0.01 μg/mL to 10 μg/mL in cell culture media, with dose-dependent telomerase upregulation observed across this range. Concentrations below 0.01 μg/mL typically show no measurable effect above baseline, while concentrations above 10 μg/mL do not produce proportional increases in telomerase activity — suggesting receptor saturation or compensatory downregulation at higher doses. For initial screening experiments, testing a logarithmic dose series (0.01, 0.1, 1.0, 10 μg/mL) with 24-hour and 48-hour timepoints provides comprehensive dose-response characterization.

RESEARCH USE ONLY · NOT EVALUATED BY THE FDA