Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of PE-22-28 and Selank — mechanism, side effects, legal status, and pricing.
PE-22-28 is a 7-amino-acid synthetic analog of spadin, a peptide fragment (residues 22-28) of the 44-aa propeptide (PE) released during post-translational maturation of sortilin (the neurotensin receptor-3). It is studied in preclinical models as a fast-acting antidepressant that works by selectively blocking the TREK-1 two-pore potassium channel. There is no established use for hair growth — that is a separate compound and the two should not be confused.
Selank is a synthetic heptapeptide analog of the endogenous immunomodulatory tetrapeptide tuftsin, extended with a Pro-Gly-Pro C-terminus for metabolic stability. Developed at the Institute of Molecular Genetics (Russian Academy of Sciences), it is registered as an anxiolytic drug in Russia but is not approved by the FDA or EMA.
PE-22-28
Selank
Category
Legal Status
Mechanism
Half-life
Side Effects
COA-verified vendors · trust score ≥70 required · single-vial price — bulk/bundle deals may be lower
PE-22-28
Selank
COA corpus from Disclosed Labs — independently tested batches only.
PE-22-28
13
COAs
99.6%
Avg purity
7
Labs
Selank
81
COAs
99.6%
Avg purity
18
Labs
Selank is among peptides under FDA review for the Category 1 (503A) list; if added, it would require a prescription to be compounded by registered 503A/503B pharmacies — not yet authorized. PE-22-28 remains research-only. In April 2026 the FDA removed 12 peptides from Category 2, which does not place them on the Category 1 list or authorize compounding. The FDA's Pharmacy Compounding Advisory Committee is advisory and meets July 23–24, 2026 to review nominations and make recommendations to the FDA.
Mazella, Borsotto and colleagues at Nice, France identified spadin (Mazella et al., PLoS Biology 2010, PMID 20405001) and subsequently developed shortened PE 22-28 analogs with ~300× improved TREK-1 affinity and longer in vivo half-life (Djillani et al., Front Pharmacol 2017, PMID 28955242). In mouse antidepressant assays (forced swim, tail suspension, novelty-suppressed feeding), acute or 4-day IP dosing at ~3–4 μg/kg produced effects comparable to chronic SSRI treatment; oral gavage at 1 mg/kg was also active. The G/A-PE 22-28 modification extended duration of action to ~21–23 hours. Chronic dosing did not produce cardiac or seizure signals in rodents. No human clinical trials have been conducted. A detailed review of TREK-1 blockers for depression is available in Djillani et al., Pharmacol Ther 2019 (PMID 30291907).
Key references
Selank's clinical evidence base is almost entirely Russian. Zozulia et al. (2008, Zh Nevrol Psikhiatr Im S S Korsakova; PMID 18454096) compared selank to medazepam in 62 patients with generalized anxiety disorder and neurasthenia, reporting comparable anxiolytic efficacy plus antiasthenic/psychostimulant effects, together with changes in serum enkephalin-degrading enzyme activity. Mechanistic work includes Inozemtseva et al. (2008, Dokl Biol Sci; PMID 18841804) showing intranasal Selank increases hippocampal BDNF mRNA and protein in rats, Volkova et al. (2016, Front Pharmacol; PMID 26924987) demonstrating modulation of GABAergic gene expression, and Vyunova et al. (2018, Protein Pept Lett; PMID 30255741) proposing a positive allosteric GABA-A mechanism. No US or EU regulatory clinical trials have been conducted; safety data outside Russia is limited.
PE-22-28 and Selank are both in the Cognitive category and may have overlapping mechanisms. Researchers should review both profiles carefully, understand the mechanisms of action, and monitor the relevant biomarkers when combining compounds in the same class. As always, consult a licensed healthcare provider before making any decisions about combining research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Key references
Disclosed Labs