PE-22-28
NootropicsPreclinicalAlso known as: PE2228
PE-22-28 is a synthetic seven-amino-acid peptide (sequence PAGASRLLLLTGEIDLP derivative, commonly truncated to PE-22-28 as shorthand for "position 22-28" within the parent humanin-family sequence) that was designed as an analog of Humanin with specific interest in activity at glutamate transporter regulation and cytoprotective signaling relevant to depression and neuroprotection. The peptide emerged from a research program characterizing short analogs of humanin that retain bioactivity while simplifying the structure for synthetic accessibility and potential therapeutic development.
Overview
At A Glance
PE-22-28's proposed mechanism of action is derived from its relationship to the parent Humanin peptide and from specific preclinical data examining its effects on glial glutamate transporter expression and function. Humanin is a 24-amino-acid mitochondrial-derived peptide with we…
Mechanism of Action
PE-22-28's proposed mechanism of action is derived from its relationship to the parent Humanin peptide and from specific preclinical data examining its effects on glial glutamate transporter expression and function. Humanin is a 24-amino-acid mitochondrial-derived peptide with well-established cytoprotective activity mediated through binding to a receptor complex involving CNTFR-alpha, WSX-1, and gp130, which activates STAT3 signaling and Bax sequestration away from the mitochondrial outer membrane (Hashimoto et al., 2001). Short analogs of humanin, including the S14G-humanin variant and various truncations, have been characterized in efforts to identify the minimal sequence required for activity and to develop more pharmacologically tractable molecules. PE-22-28 represents one such analog, retaining residues from the central region of humanin that are thought to contribute to receptor binding and cytoprotective signaling while omitting flanking residues that may contribute to other activities. The specific mechanism that distinguishes PE-22-28 in published work relates to glutamate transporter regulation in astrocytes. Glutamate transporter 1 (GLT-1, encoded by SLC1A2; also known as EAAT2 in humans) is the principal glial glutamate transporter responsible for clearing synaptically released glutamate from the extracellular space, and dysfunction of GLT-1 has been implicated in depression, epilepsy, neurodegenerative disease, and ischemic brain injury. Preclinical work with PE-22-28 has reported that the peptide increases GLT-1 expression or function in relevant cellular and animal models, producing functional consequences on glutamate homeostasis that could underlie the behavioral effects observed in depression-relevant assays. The connection between glutamate homeostasis and depression has been firmly established over the past two decades through multiple lines of evidence: the rapid antidepressant effects of ketamine (an NMDA receptor antagonist) demonstrate the causal importance of glutamatergic signaling in depression; postmortem studies of depressed patients show alterations in glial glutamate transporter expression; riluzole (a glutamate release inhibitor and transporter modulator) has shown antidepressant activity in clinical trials; and animal models of chronic stress consistently show reductions in GLT-1 function and astrocyte morphology. A compound that selectively increases GLT-1 function would therefore have a mechanistically coherent rationale for antidepressant activity, connecting classical monoamine-based antidepressant research to contemporary glutamatergic models. Beyond GLT-1 regulation, PE-22-28's humanin-family origin suggests activity at the humanin receptor complex with downstream STAT3 activation, which would produce cytoprotective effects in neurons similar to those described for humanin itself. These include reduced apoptosis in response to various stressors, improved mitochondrial function in stressed neurons, and anti-inflammatory effects in brain tissue. The mitochondrial protective effects connect to depression pathophysiology through the role of mitochondrial dysfunction in mood disorders, which has been increasingly recognized through research on metabolic and cellular correlates of depression. The mechanistic profile also includes effects on neuroinflammation, which is relevant because chronic low-grade neuroinflammation is implicated in both depression and neurodegenerative disease. Humanin and its analogs have anti-inflammatory activity in multiple preclinical models, and PE-22-28 would be expected to share this activity though direct evidence in PE-22-28-specific studies is limited. The effect on glial cells extends beyond glutamate transporter regulation to broader astrocyte function, including the regulation of extracellular potassium, water homeostasis through aquaporin regulation, and support of synaptic plasticity. Astrocyte dysfunction is increasingly recognized as a contributor to depression and other neuropsychiatric conditions, and interventions that support astrocyte function through multiple mechanisms (including both glutamate transport and broader homeostatic functions) may have therapeutic relevance. The mechanism has important limitations that should be understood. First, the specific binding affinities, target selectivity, and dose-response relationships for PE-22-28 at its putative targets have not been characterized as thoroughly as they have for more mature drug candidates. Second, the translation of a 7-amino-acid peptide from peripheral administration to CNS effects requires either direct CNS delivery (which PE-22-28 is not formulated for) or adequate blood-brain barrier penetration (which is not well characterized). Third, the preclinical behavioral data driving interest in the compound rest on a small number of studies that have not been extensively replicated. Fourth, the comparison to humanin, while mechanistically grounded, may overstate the similarity — short analogs of peptides often have substantially different pharmacology than the parent compound, and assuming that PE-22-28 recapitulates humanin biology in detail is a mechanistic leap rather than an established fact. Users relying on the mechanism as rationale should understand that "proposed mechanism" is a weaker claim than "demonstrated mechanism" and that proposed mechanisms do not always survive contact with detailed clinical investigation.
Overview
PE-22-28 is a synthetic seven-amino-acid peptide (sequence PAGASRLLLLTGEIDLP derivative, commonly truncated to PE-22-28 as shorthand for "position 22-28" within the parent humanin-family sequence) that was designed as an analog of Humanin with specific interest in activity at glutamate transporter regulation and cytoprotective signaling relevant to depression and neuroprotection. The peptide emerged from a research program characterizing short analogs of humanin that retain bioactivity while simplifying the structure for synthetic accessibility and potential therapeutic development. PE-22-28 specifically attracted attention when preclinical work suggested antidepressant-like activity in rodent models of depression, with a proposed mechanism involving glial cell modulation and glutamate transporter 1 (GLT-1/EAAT2) regulation. The compound sits in the broader field of peptide-based neuropsychiatric therapeutics, alongside compounds like Selank and Semax that have been used in Russia for decades but remain investigational in Western markets. PE-22-28 is distinctive within this space because of its mechanistic grounding in humanin biology and glutamate homeostasis, which connects it to contemporary understanding of depression pathophysiology that emphasizes the role of glutamatergic signaling, astrocyte function, and neuroinflammation alongside the classical monoamine framework. The practical reality in April 2026 is that PE-22-28 remains a preclinical research peptide with limited published literature, no approved human use, no registered clinical trials, and a small but active self-experimentation community among biohackers interested in short peptide therapeutics for mood and cognitive applications. The compound is sold by research-chemical peptide vendors with the standard "for research purposes only" framing, and individual users have accumulated anecdotal experience with it in protocols typically involving daily or every-other-day subcutaneous dosing. The evidence base for PE-22-28 is substantially thinner than for BPC-157, Selank, or Semax in terms of published animal studies and translational groundwork; the peptide's profile rests on specific rodent behavioral studies and mechanistic biology inferred from its relationship to humanin and its proposed interactions with glutamate transporter regulation. This entry covers what is published about the peptide, the mechanistic rationale connecting it to humanin biology and glutamate homeostasis, the specific preclinical behavioral data that sparked interest in depression applications, realistic interpretation of that data in the context of the replication crisis in preclinical depression research, the theoretical and practical concerns with self-administration of a minimally characterized peptide, how PE-22-28 fits into the peptide stacking landscape alongside other cytoprotective and neuropsychiatric peptides, and what conservative thinking about this molecule looks like for someone considering it seriously rather than as a novelty.
Chemical Information
IUPAC Name
Not yet available
CAS Number
Not yet available
Molecular Formula
C141H237N43O40S
Molecular Mass
3213.92 g/mol
Dosing & Protocols
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Interactions
Interaction Matrix
Contraindications
PE-22-28's proposed mechanism as a glutamate transporter modulator and humanin-family analog creates a contraindication profile focused on psychiatric conditions, seizure disorders, pregnancy, and medication interactions. Active severe psychiatric illness requiring stabilization is a relative contraindication. Major depressive disorder with suicidality, active psychosis, severe bipolar disorder, and severe anxiety disorders should be managed with evidence-based treatments under the care of a qualified mental health professional, not with research-chemical peptides. PE-22-28 may be a consideration as an experimental adjunct for milder or treatment-resistant depression in users who have already tried evidence-based treatments and are pursuing additional options with appropriate clinical support, but it should not be a first-line approach or a substitute for professional care in severe illness. History of bipolar spectrum disorders warrants specific caution because any agent that affects mood regulation carries theoretical risk of inducing mania, hypomania, or mood cycling. Users with bipolar history should avoid PE-22-28 unless explicitly supervised by a psychiatrist who can monitor for mood destabilization. Psychosis spectrum disorders warrant caution because of the unknown effects of glutamatergic modulation in these conditions; glutamate abnormalities are implicated in schizophrenia, and pharmacologic interventions affecting glutamate signaling have unpredictable effects in psychosis. Users with psychosis history should avoid unsupervised use. Seizure disorders are a relative contraindication because glutamate transporter modulation could affect seizure threshold. Upregulation of GLT-1 would theoretically raise seizure threshold (potentially beneficial for epilepsy), but the interaction with anticonvulsant therapy is not characterized, and any change to the pharmacologic environment of seizure control should be made with neurological supervision. Users with epilepsy should not use PE-22-28 without explicit neurologist consultation. Pregnancy and breastfeeding are absolute contraindications. PE-22-28 has no pregnancy safety data, and pharmacologic modulation of glutamate homeostasis during fetal neurodevelopment or during early postnatal brain maturation could have lasting effects. The peptide should not be used during pregnancy or while breastfeeding. Women trying to conceive should discontinue at least 2-4 weeks before attempting conception. Children and adolescents should not use PE-22-28 because glutamatergic signaling plays critical roles in brain development and maturation through adolescence, and chronic pharmacologic modulation during these periods could produce lasting effects on adult neurophenotype. Active cancer, particularly brain tumors, warrants avoidance because glutamatergic signaling is involved in tumor biology in complex ways; some brain tumors depend on glutamate signaling for proliferation, others are suppressed by it, and pharmacologic modulation in these contexts is uncharacterized. Users with cancer history should consult with oncology before use. Recent head injury or stroke is a relative contraindication because glutamate toxicity is a key mechanism of acute neurological injury, and pharmacologic modulation of glutamate transport during acute recovery could either help or harm depending on specific timing and context. A general guideline is to avoid PE-22-28 for at least 3-6 months after significant head injury or stroke, with specific timing determined in consultation with neurology. Active ketamine therapy (whether for depression, pain, or other indications) is an important interaction concern. Both ketamine and PE-22-28 affect glutamatergic signaling, albeit through different mechanisms (NMDA antagonism for ketamine, glial transporter modulation for PE-22-28). Combining them could produce unpredictable effects on glutamate homeostasis and mood. Users receiving ketamine therapy should not add PE-22-28 without explicit physician supervision. Lithium, valproate, and other mood stabilizers have established effects on mood regulation and neuropsychiatric function, and combining them with PE-22-28 adds uncharacterized pharmacology to an established regimen. Patients on these medications should discuss with their psychiatrist before use. SSRI and SNRI antidepressants may interact with PE-22-28's proposed mood effects through overlapping effects on neurotransmitter systems. Serotonin syndrome is a theoretical concern with any combination of serotonergic drugs, though PE-22-28 is not primarily serotonergic. Users on antidepressants should discuss with their prescriber before adding PE-22-28. MAOIs carry particular interaction concern because of the broad effects on neurotransmitter metabolism and should be combined with any experimental compound only under explicit supervision. NMDA receptor antagonists (memantine, ketamine, dextromethorphan at high doses) have direct glutamatergic effects that could interact with PE-22-28. Combined use is not recommended. Anticonvulsants and GABAergic agents may interact with the excitatory-inhibitory balance that PE-22-28 would be expected to shift toward inhibition; users on these medications should maintain seizure control monitoring. Known hypersensitivity to peptide products or to any component of the preparation (including bacteriostatic water preservative) is an absolute contraindication. The final and most important contraindication is the absence of clinical infrastructure adequate for safe self-experimentation with a compound targeting the CNS for a psychiatric indication. Users contemplating PE-22-28 for depression should have ongoing engagement with mental health care (psychiatrist, therapist, or both), should not rely on peptides as a substitute for established treatments, and should have a plan for escalating care if symptoms worsen. Users without this infrastructure are taking on both pharmacologic risk and the additional risk of treating a serious condition without appropriate support.
Research Disclaimer
This interaction data is compiled from published research and community reports. It may not be exhaustive. Always consult a healthcare professional before combining compounds.
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Protocols, calculator & safety for PE-22-28
Research Score
1 PubMed studies
Quality Indicators
Data Completeness
88%Research Credibility
Limited research available
Quick Facts
Molecular Weight
3213.92 g/mol
Trial Phase
Preclinical
Research Disclaimer
This information is for educational and research purposes only. Not intended as medical advice. Consult a healthcare professional before use.
Frequently Asked Questions
What is PE-22-28 and how is it related to humanin?
PE-22-28 is a synthetic 7-amino-acid peptide derived from the parent mitochondrial-derived peptide Humanin. It represents residues 22-28 of an extended humanin-family sequence and was developed as an analog retaining cytoprotective signaling activity while simplifying the structure. It has been investigated primarily for antidepressant-like effects in rodent models, with a proposed mechanism involving glial glutamate transporter 1 (GLT-1/EAAT2) upregulation.
Has PE-22-28 been tested in humans?
No. As of April 2026, no Phase 1 or later clinical trials of PE-22-28 have been published, no IND applications have been publicly disclosed, and no registered trials appear on ClinicalTrials.gov. All human use is self-experimentation with research-chemical peptide vendor supply. The evidence base is entirely preclinical.
How does PE-22-28 work for depression?
The proposed mechanism involves upregulation of glutamate transporter 1 (GLT-1) in astrocytes, which is responsible for clearing synaptically released glutamate. Dysfunction of GLT-1 has been implicated in depression pathophysiology, and pharmacologically enhancing its function could improve glutamate homeostasis in brain regions relevant to depression. The mechanism is plausible and connects to contemporary understanding of glutamatergic contributions to depression, but clinical efficacy has not been demonstrated in humans.
What dose of PE-22-28 is typically used?
Self-report community doses range from 250-2000 micrograms per injection subcutaneously, with 500 mcg once daily or every other day being a common starting point. Beginners typically use 250-500 mcg daily for 4-6 week cycles; intermediate users run 500-1000 mcg for 6-8 weeks; advanced users go up to 1000-2000 mcg. These doses are empirical extrapolations from rodent studies and have no clinical validation in humans.
How long before PE-22-28 effects are noticeable?
Self-report community reports describe onset of subjective effects over days to weeks of daily dosing, consistent with a proposed mechanism involving transcriptional upregulation of GLT-1 rather than acute receptor-mediated signaling. Users report variable response timing — some notice effects within the first week, others require several weeks, and some report no effects at all. The pattern suggests that if PE-22-28 has an effect, it is typically gradual rather than acute.
Is PE-22-28 safe for long-term use?
Unknown. No long-term safety data exist in humans or in extended rodent studies. Theoretical concerns include effects of chronic glutamate transporter modulation on neural adaptation, effects of sustained humanin-family signaling on cellular processes including apoptosis, and effects of long-term peptide administration on immune function. Conservative use patterns involve cycling on and off rather than continuous chronic administration, and monitoring for any subtle or delayed adverse effects.
Can I combine PE-22-28 with my antidepressant medication?
Any combination of PE-22-28 with prescription antidepressants should be discussed with the prescribing physician before starting. Theoretical interactions exist with SSRIs, SNRIs, and other antidepressants through overlapping effects on neurotransmitter signaling. Users should not substitute PE-22-28 for prescribed medications, should not discontinue prescribed medications to use PE-22-28, and should maintain regular psychiatric follow-up if they add any experimental compound to established treatment.
What are the main side effects of PE-22-28?
Documented side effects are limited because no clinical trials have been conducted. Self-report community users describe occasional headaches, mild fatigue or sedation in some users, injection site reactions typical of subcutaneous peptide administration, and rare reports of emotional sensitivity or anxiety. Paradoxical worsening of mood is possible with any mood-modulating compound. Pyrogen contamination in research-chemical supply can produce flu-like symptoms that may be misattributed to the peptide itself.
Can PE-22-28 be used for anxiety, not just depression?
Preclinical studies have examined PE-22-28 primarily in depression-relevant behavioral paradigms, but the proposed mechanism (glutamate transporter modulation) has theoretical relevance to anxiety disorders as well given the role of glutamatergic signaling in fear and anxiety circuitry. Self-report community use includes anxiety as a target symptom, with mixed reports of efficacy. No controlled data exist for anxiety applications specifically. Users with significant anxiety disorders should pursue evidence-based treatment options alongside any experimental peptide use.
Is PE-22-28 worth trying given the limited evidence?
The decision depends on the user's risk tolerance, financial resources, existing mental health support, and willingness to experiment with an unvalidated compound. For someone with mild to moderate subclinical mood symptoms, adequate clinical support, and resources to test the compound in a structured way, PE-22-28 represents a reasonable experimental option alongside established approaches (therapy, exercise, sleep, established medications as appropriate). For someone with severe depression, limited clinical support, or unstable life circumstances, self-treatment with a research-chemical peptide is not an adequate approach and professional care should be the priority. The limited evidence means that users should enter with realistic expectations and be prepared to conclude that the compound does not work for them.
Research Tools
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Bromantane
NootropicsRussia ApprovedBromantane is an atypical psychostimulant and anxiolytic developed in the 1980s at the Zakusov Institute of Pharmacology of the Russian Academy of Medical Sciences, originally created as an adaptogen for Soviet military and elite athletic use and later approved in Russia for the treatment of neurasthenic and asthenic disorders under the trade name Ladasten.
Dihexa
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Kavain
NootropicsPreclinicalActive compound from kava for relaxation and sleep support..
L-Theanine
NootropicsFDA ApprovedL-Theanine is a non-proteinogenic amino acid found almost exclusively in tea (Camellia sinensis) and a handful of edible mushrooms, and it has become the single most widely-used calm-focus nootropic in the modern supplement market — both on its own at 100-400mg doses and, even more prominently, as the classic 1:1 or 2:1 pair with caffeine that defines the "calm-focus" experiential signature of green tea and of virtually every serious nootropic stack.
L-Tyrosine
NootropicsPreclinicalL-Tyrosine is a non-essential aromatic amino acid and the direct biosynthetic precursor to the catecholamine neurotransmitters dopamine, norepinephrine, and epinephrine.
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