Peptides for Anxiety and Mood: Selank, Semax and What They Are Not

Anxiety, at the level of the brain, is a threat-detection system running with the gain turned up. The amygdala flags a stimulus as dangerous, the prefrontal cortex is supposed to evaluate that flag and dampen it, and when the balance tips toward the amygdala the result is a body braced for something that is not happening. The brain's main inhibitory signal, GABA, is the brake on that circuit. Benzodiazepines amplify GABA's action, which is why they calm quickly and also why they sedate, dull memory and produce dependence. The research interest in Selank rests on the claim that it touches GABA-related signaling without those three costs, which is the central question of the whole Selank literature.

The second system is the hypothalamic-pituitary-adrenal axis. Under stress the hypothalamus releases CRH, the pituitary responds with adrenocorticotropic hormone (ACTH), and the adrenal glands make cortisol. In sustained stress that loop stops switching off cleanly, and chronically raised cortisol is one of the better-replicated biological findings in both anxiety and depression. Semax is a fragment of ACTH, which sounds alarming until the detail is understood: the fragment used is the part with effects on the brain, not the part that tells the adrenal glands to make cortisol, and it is not described as driving cortisol production. DSIP, the sleep peptide in SERENITY, was reported in a 1985 Neuroendocrinology study to reduce CRF-induced corticosterone release in animals, the same axis from the other end.

The third piece is brain-derived neurotrophic factor, BDNF, a protein that governs how neurons grow, connect and adapt. Reduced BDNF signaling in the hippocampus and prefrontal cortex is a consistent finding in depression research, and the delayed onset of conventional antidepressants is often explained by the weeks it takes for BDNF-driven changes to accumulate. Both Selank and Semax are described in rat studies as raising BDNF expression in the hippocampus, and PE-22-28's whole rationale is a faster route to the same downstream changes. This is why these peptides are discussed as mood compounds at all, and also why the honest framing is "described in animals," because every one of those BDNF papers is a rodent study.

The fourth piece is the reason ELEVATE exists. Inflammation and mood track together: people with inflammatory bowel disease have higher rates of anxiety and depression, inflammatory signaling molecules reach the brain, and the gut produces a large share of the body's serotonin. A 2016 review in Current Neuropharmacology set out the theoretical case for BPC-157 and the brain-gut axis, and Selank itself was reported to have immunomodulatory effects in patients with anxiety-asthenic disorders in a 2008 Russian clinical paper. None of this establishes that treating the gut treats the mood; it establishes that the two are connected, which is a hypothesis a physician may reasonably act on, not a settled mechanism.

Selank is a synthetic heptapeptide built from tuftsin, a four-amino-acid immune fragment of an antibody molecule, with a Pro-Gly-Pro tail added so it survives longer in the body. It was developed at the Institute of Molecular Genetics in Moscow, and the Russian literature on it goes back to the 1990s.

Three mechanisms are described. A 2001 Bulletin of Experimental Biology and Medicine paper reported that Selank inhibits enkephalin-degrading enzymes, which would prolong the action of the body's own opioid-family peptides that damp anxiety; the authors proposed this as a possible basis for its anxiolytic effect. A 2016 Frontiers in Pharmacology study reported that Selank changed the expression of genes involved in GABAergic neurotransmission in rats, with a 2017 follow-up in a human neuroblastoma cell line. A 2008 Doklady Biological Sciences study reported that intranasal Selank regulated BDNF expression in the rat hippocampus, and a 2019 Bulletin of Experimental Biology and Medicine paper reported it protected against ethanol-induced memory impairment in rats through BDNF in the hippocampus and prefrontal cortex. A 2018 review in Protein and Peptide Letters pulls the molecular work together.

The human evidence is what separates Selank from everything else on this page. A 2008 paper in the Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova reported on Selank in the treatment of generalized anxiety disorder and neurasthenia; a 2014 paper in the same journal compared its anxiolytic effect and tolerability with phenazepam, a Russian benzodiazepine, in patients with anxiety disorders; a 2015 paper looked at optimizing anxiety-disorder treatment with it. These are real patient studies with a benzodiazepine comparator, which is more than most compounded peptides can say. They are also small, published in Russian with English abstracts, conducted within one research tradition, and not replicated in a Western randomized trial. A 2021 review in the Journal of Clinical Pharmacology, written for US clinicians, covered Selank alongside other GABA-acting agents and is the most accessible English-language summary of what is and is not known.

Selank suits the person whose problem is situational anxiety and low stress tolerance: the reactivity, the bracing, the poor recovery after a stressful day. It is not a treatment for an anxiety disorder and does not replace one.

Selank Nasal Spray is the same molecule delivered through the nose, which is how it has most often been given in the research; a 2016 Eksperimental'naia i Klinicheskaia Farmakologiia study compared its effects after intranasal and intraperitoneal administration in two mouse strains and reported activity by both routes. The nasal form suits the person who will not inject, or who wants something they can use through the day; the vial carries more total peptide per container. Neither route is better in general, and your physician chooses.

Semax is a synthetic heptapeptide built from the 4–7 fragment of ACTH with the same Pro-Gly-Pro tail as Selank. The ACTH fragment retained is the one with effects on the brain; the part of the hormone that signals the adrenal glands to make cortisol is not included, so Semax is not a stress hormone and is not described as raising cortisol.

The mechanistic work is again mostly rat. A 2006 Brain Research paper reported that Semax regulated BDNF and its receptor trkB in the rat hippocampus; a 2010 Cellular and Molecular Neurobiology study reported that Semax activated neurotrophin gene transcription after cerebral ischemia; a 2014 BMC Genomics analysis described it affecting immune and vascular genes in rat focal ischemia. A 2024 European Journal of Pharmacology study reported antidepressant-like and antistress effects of Semax in male rats under chronic unpredictable stress, which is the closest the Semax literature comes to the mood question, and it is an animal study.

The human evidence is concentrated in Russian stroke work: a 1997 clinical and electrophysiological study in acute hemispheric ischemic stroke, a 2005 paper on cerebrovascular insufficiency, and a 2018 study of Semax at different stages of ischemic stroke, all in the Korsakov journal. There is also a 2018 Bulletin of Experimental Biology and Medicine fMRI study of Semax's effects on the brain's default mode network in healthy volunteers, and a 2020 Doklady Biological Sciences study of 52 healthy participants that imaged resting-state connectivity before and after Semax, Selank or placebo and reported effects of both peptides on connectivity between the right amygdala and the right temporal cortex. Semax is a registered drug in Russia, available as 0.1% and 1% nasal drops, which the FDA's own July 2026 briefing document acknowledges. A 2007 Medical Hypotheses paper proposed it for attention-deficit hyperactivity disorder; it is a hypothesis paper, not a trial.

Semax suits the person whose complaint is mental fatigue, poor sustained attention and flat motivation rather than anxiety. It is not a stimulant, it is not prescribed for anxiety, and there are no randomized human trials of Semax for depression or for attention deficit in those words.

Semax Nasal Spray is the format closest to how the molecule has been studied and how it is registered abroad; a 2006 Bioorganicheskaia Khimiia study measured Semax reaching the brain and blood of rats after intranasal administration. It suits the person who wants the attention effect without a needle.

Semax + Selank puts both molecules in a single vial for the person whose picture is both: reactivity and poor focus at once, which is common because sustained anxiety degrades attention. The two share a Pro-Gly-Pro tail and a research origin, and the 2020 Doklady Biological Sciences imaging study is the one paper that examined them side by side in the same healthy participants. Combining them is a physician's decision, and it is sensible only when both targets are actually present.

PE-22-28 is a seven-amino-acid fragment of spadin, itself a fragment of the sortilin propeptide. Its target is TREK-1, a background potassium channel in neurons. The story starts with a 2006 Nature Neuroscience paper reporting that mice lacking TREK-1 had a depression-resistant phenotype, and a 2010 PLoS Biology paper describing spadin as a TREK-1 blocker with antidepressant-like activity in rodents. A 2012 Neuropharmacology paper reported spadin lacked the side effects expected from TREK-1 blockade in animals, a 2015 British Journal of Pharmacology paper described it regulating synaptogenesis, and a 2017 Frontiers in Pharmacology paper introduced the shortened analogs, of which PE 22-28 was the lead, reporting better TREK-1 inhibition, in vivo stability and antidepressant-like activity in mice. A 2019 Pharmacology and Therapeutics review summarizes the field.

Two human papers exist, and neither is a treatment trial: a 2017 Journal of Affective Disorders study reported that serum sortilin-derived propeptide concentrations were decreased in patients with major depressive disorder, and a 2018 Neuropsychiatric Disease and Treatment paper reported them rising after electroconvulsive therapy in treatment-resistant patients. Those are biomarker observations. There are no randomized human trials of PE-22-28, and no human trials of it at all. PE-22-28 is priced on its product page, and anyone presenting it as a depression treatment is well ahead of the evidence. Where a physician considers it, it is for a patient already under psychiatric care whose mood is being managed by treatments with evidence, and who understands they are using a preclinical compound.

ELEVATE Blend pairs Semax and Selank with BPC-157 and KPV for the person whose stress and mood complaints arrive with gut and inflammation complaints. BPC-157 is a fifteen-amino-acid fragment of a protein found in human gastric juice, studied in animals for protection of the gastrointestinal lining; the 2016 Current Neuropharmacology brain-gut review and the 2022 Neural Regeneration Research review on its central nervous system effects are the relevant reading. KPV is the last three amino acids of alpha-melanocyte-stimulating hormone; a 2008 Gastroenterology study reported that KPV taken up through the PepT1 transporter reduced intestinal inflammation in mouse models of colitis. Their place in a mood formula rests on the gut-inflammation-mood connection described above, which is a hypothesis rather than a settled mechanism. ELEVATE Blend suits the person with a documented gut complaint and a stress complaint, not the person with anxiety alone.

SYNAPSE Blend pairs Semax and Selank with MOTS-c and tesamorelin for cognitive complaints that arrive alongside metabolic ones: the person whose mental fatigue tracks with weight, blood sugar or visceral fat. Tesamorelin is the one component on this page with an FDA-approved reference product, Egrifta, approved in 2010 for excess abdominal fat in HIV-associated lipodystrophy; a 2013 JAMA Neurology study reported effects of growth-hormone-releasing hormone on brain GABA levels in mild cognitive impairment and healthy aging, which is the thread that connects it to a cognition blend. MOTS-c is a mitochondrial-derived peptide described in a 2015 Cell Metabolism mouse study as promoting metabolic homeostasis. SYNAPSE Blend is the wrong choice for anxiety on its own and the right conversation only when the metabolic picture is real.

SERENITY Blend puts Selank alongside DSIP, CJC-1295 and ipamorelin for anxiety that mainly shows up at bedtime. DSIP, delta sleep-inducing peptide, has small human trials from the 1980s and early 1990s: a 1981 Lancet report in insomniacs and a 1992 double-blind Neuropsychobiology study in chronic insomniac patients, with results a 2006 Journal of Neurochemistry review called "a still unresolved riddle." CJC-1295 and ipamorelin are growth hormone secretagogues included for the overnight growth hormone pulse. SERENITY Blend is covered in full in peptides for sleep; here the point is that Selank is the anxiety component, and a physician chooses this blend only when the night, not the day, is where the anxiety lives.

Selank is the only peptide on this page with human trials in anxiety. The 2008, 2014 and 2015 Korsakov journal papers studied patients with generalized anxiety disorder, neurasthenia and anxiety disorders, and the 2014 paper used phenazepam as an active comparator. What those papers report is anxiolytic activity with better tolerability than the benzodiazepine, and without its sedation. What they do not provide is a large, Western, placebo-controlled randomized trial, a published effect size in units a US clinician would recognize, or long-term safety data. There are no randomized human trials of Selank outside that Russian tradition.

Semax's human record is in ischemic stroke, in Russian clinical studies, and in fMRI work in healthy volunteers. The FDA's July 2026 briefing document noted that the Russian-language references could not be considered because full texts were not available in English, and that the neuroprotective and nootropic studies it could find were in healthy adults. There are no randomized human trials of Semax for depression, anxiety or attention deficit. The 2024 European Journal of Pharmacology antistress findings are in rats.

There are no human trials of PE-22-28. The two human papers on sortilin-derived propeptides are biomarker studies in depressed patients, not treatment studies. Everything about its antidepressant-like activity is rodent work, and it should be read as a mechanism that has not yet been tested in people.

In one place, the human data: Selank has small Russian patient studies in anxiety disorders, one with a benzodiazepine comparator, and fMRI in healthy volunteers; Semax has Russian stroke studies, fMRI in healthy volunteers and a registered nasal product in Russia; PE-22-28 has none; DSIP has small insomnia trials from the 1980s and 1990s with mixed results; BPC-157 and KPV have animal and cell work and no human mood data.

• It does not establish that any of these peptides treats generalized anxiety disorder, panic disorder, social anxiety disorder or major depression. Those conditions have treatments with strong evidence, and a peptide is not one of them.
• It does not establish an effect size or a response rate in a US population.
• It does not establish a human timeline; the windows described later on this page are patient reports.
• It does not establish long-term safety over years of use.
• It does not establish an interaction profile with SSRIs, SNRIs, benzodiazepines or antipsychotics, because those studies have not been run. That is why the medication list on the intake matters.

Every product on this page is compounded by a state-licensed pharmacy to a physician's prescription. The FDA's own compounding Q&A states: "Compounded drugs are not FDA-approved. This means that FDA does not verify the safety, effectiveness or quality of compounded drugs before they are marketed." Under section 503A, a pharmacy may compound with a bulk substance only if it has a USP or NF monograph, is a component of an FDA-approved drug, or appears on the 503A bulks list; the FDA also sorts nominated substances into three interim categories, and has said it will not place substances nominated on or after 7 January 2025 into those categories at all. The positive list at 21 CFR 216.23 still holds the six substances placed there in 2019, none of them a peptide.

On 15 April 2026 the FDA announced the removal of twelve peptides from Category 2 of its interim 503A list, the category for nominated substances flagged as raising significant safety risks, effective about a week later, and was explicit that removal from Category 2 does not by itself place a substance on the bulks list or into Category 1. The FDA's safety-risks page, current as of 22 April 2026, now lists Semax, Selank acetate (TP-7), emideltide, CJC-1295, ipamorelin acetate, BPC-157, KPV and MOTS-c under substances "nominated but withdrawn." The categories document updated 14 May 2026 carries none of the peptides on this page in Category 1, 2 or 3; Category 2 under 503A is down to six substances: cesium chloride, domperidone, germanium sesquioxide, ibutamoren mesylate, kisspeptin-10 and quinacrine hydrochloride for intrauterine use.

Selank has a different history from the peptides that made the news in 2026. Selank acetate was placed in Category 2 in September 2023. In the FDA's list updated 27 September 2024, the agency recorded that "Selank acetate (TP-7)" had been removed from Category 2 "because FDA received additional information from the nominator indicating that they intended to nominate a different bulk drug substance." The nomination was withdrawn as a mistake rather than resolved on the science, a year and a half before the April 2026 removals. It now sits among substances nominated but withdrawn, appears in no category on the 14 May 2026 list, was not on the July 2026 advisory committee agenda, and is not among the five substances the committee will consider before the end of February 2027. So: not flagged as a safety risk since 2024, never evaluated by the committee, no active nomination.

Semax was placed in Category 2 in 2023 and is now listed as nominated but withdrawn. The FDA brought it to its Pharmacy Compounding Advisory Committee on 24 July 2026, as Semax free base and Semax acetate, for the nominated uses of cerebral ischemia, migraine and trigeminal neuralgia. The FDA's briefing document concluded that "a balancing of the criteria weighs against" listing: it judged both forms not well characterized, could not rule out immunogenicity from aggregation and peptide-related impurities for the injectable and nasal routes, and found "insufficient evidence of effectiveness" for the nominated uses on the English-language material available. It also noted that Semax products are "widely marketed in the United States" for anxiety, depression and attention, among other things. The committee voted 8–5, with one abstention, to recommend adding Semax to the 503A Bulks List, one of six peptides it recommended that week over the objection of FDA's own reviewers. A committee vote is advice, not a decision. The FDA issues its own determination afterwards, and as of September 2026 it has not.

PE-22-28 does not appear in Category 1, 2 or 3 of the 14 May 2026 document, does not appear on the safety-risks page either in the Category 2 table or among withdrawn substances, was not on the July 2026 agenda, and is not on the 21 CFR 216.23 list. No safety notice, no vote either way; it has simply not been through the process.

BPC-157 and KPV were reviewed on 23 July 2026 and each recommended 8–6 with one abstention; MOTS-c was recommended 7–5 with two abstentions; all three against FDA staff recommendations. DSIP, which the FDA lists as emideltide, was reviewed on 24 July 2026 for opioid withdrawal, chronic insomnia and narcolepsy; the FDA's briefing document called the insomnia evidence "inconclusive and at best preliminary," and the committee voted 6 in favor, 7 against, with 1 abstention, and so did not recommend adding emideltide, the only one of the seven peptides that week not to receive a favorable vote. CJC-1295 and ipamorelin were each voted against in late 2024 and have since been withdrawn; ipamorelin acetate remains in Category 2 only under the separate 503B policy for outsourcing facilities, which is a different pathway from the 503A pharmacy compounding of a patient-specific prescription. Tesamorelin is the active ingredient of an approved product and has never been in the 503A categories.

The plain-English version of all of this is in are peptides FDA approved. None of it changes the basic position: each of these is legal for a licensed physician to prescribe and a state-licensed pharmacy to compound, and none is an FDA-approved drug product.

The 2026 WADA Prohibited List, in effect from 1 January 2026, does not name Selank, Semax, PE-22-28 or DSIP. It does name BPC-157 in section S0, non-approved substances, prohibited at all times, which covers ELEVATE Blend; and it lists CJC-1295, tesamorelin and ipamorelin under S2.2.4, growth hormone releasing factors, which covers SERENITY Blend and SYNAPSE Blend. Semax's parent hormone class, corticotrophins, appears at S2.2.2, and a tested athlete should ask their anti-doping body about an ACTH fragment before assuming anything.

An overactive thyroid produces a picture clinically indistinguishable from an anxiety disorder: racing heart, tremor, heat intolerance, insomnia and a mind that will not settle. An underactive one produces low mood, fatigue and slowed thinking. Both are a blood test, as are blood sugar swings and iron or B12 deficiency, which present the same way.

Fragmented sleep is one of the most reliable ways to produce anxiety and low mood in a healthy person, and obstructive sleep apnea does it every night. If the anxiety is worst in the morning, if there is snoring, or if sleep is short, the physician's first question is the night, not the peptide; that is peptides for sleep.

Caffeine past the early afternoon, alcohol in the evening, cannabis and stimulants all produce or amplify anxiety and all withdraw into low mood. Six coffees a day outrun any vial, which is why the intake asks.

If the picture is a generalized anxiety disorder, panic disorder, major depression, bipolar disorder or anything with suicidal thinking, the right response is a psychiatrist or a therapist and a treatment with evidence, not a peptide. A physician reviewing an intake should say so plainly. Where a patient already has psychiatric care, that team should be involved in any decision to add a peptide, and no provider should ever suggest reducing or stopping a psychiatric prescription.