# Selank + Semax

> The Selank + Semax blend is a supplier-defined research formulation that combines two synthetic heptapeptides: Selank, a tuftsin analog studied as an anxiolytic, and Semax, an ACTH(4-10) analog studied as a nootropic. Both end in the same Pro-Gly-Pro tripeptide. The two have been compared side by side in a few studies, but not tested as a combined formulation. Neither is FDA approved.

Canonical: https://peptideproperties.com/compounds/selank-semax/

## Identity

- **Class:** Neuropeptides & Nootropic Research Compounds

## Key facts

- Components: Selank (tuftsin analog) and Semax (ACTH(4-10) analog), both heptapeptides
- Commonly supplied as 5 mg + 5 mg or 10 mg + 10 mg
- Selank: C33H57N11O9, 751.9 g/mol; Semax: C37H51N9O10S, 813.9 g/mol
- Shared structural feature: a C-terminal Pro-Gly-Pro (glyproline) tripeptide
- Studied side by side in one human fMRI study and one rat model
- No published study of the two as a combined formulation
- Regulatory status: neither component is FDA approved

## What Is the Selank + Semax Blend?

The Selank + Semax blend is a research formulation that contains two short synthetic regulatory peptides in one product. Suppliers commonly list it in equal amounts, as 5 mg + 5 mg or 10 mg + 10 mg.Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) extends the immunomodulatory tetrapeptide tuftsin with Pro-Gly-Pro, and Semax (Met-Glu-His-Phe-Pro-Gly-Pro) joins the ACTH(4-7) fragment to the same tripeptide. The blend is a supplier-defined combination. It is not an approved or standardized product, and its composition is set by each supplier.

## Components at a Glance

Both components are glyproline-capped heptapeptides with different parent peptides and research profiles. Molecular data below are from PubChem.ComponentClassPrimary mechanism studiedMolecular weightSelankSynthetic tuftsin analog; heptapeptideGABAergic signaling (gene expression studies); studied as an anxiolytic751.9 g/molSemaxSynthetic ACTH(4-10) analog; heptapeptideBDNF regulation and specific brain binding sites; Cu(II) chelation813.9 g/mol

## Why These Compounds Are Studied Together

Selank and Semax are grouped because they share a design, a Pro-Gly-Pro tail on a natural regulatory peptide fragment, and because they have complementary research profiles: Selank as an anxiolytic and Semax as a nootropic. Published research on the specific combination is limited; no study has tested the two in one formulation.
### Separate research profiles
In rats, Selank altered the expression of genes involved in GABAergic neurotransmission in a pattern that correlated with GABA's own effects.[1] It also prevented ethanol-induced memory impairment and an ethanol-induced rise in BDNF in the hippocampus and frontal cortex.[2] Semax bound specifically to rat basal forebrain membranes and increased BDNF protein levels in that region.[3] In vitro, Semax removed Cu(II) from amyloid-beta complexes and reduced copper-catalyzed reactive oxygen species production.[4] In transgenic APPswe/PS1dE9 mice, a model of Alzheimer's disease, Semax improved performance in cognitive tests and reduced amyloid inclusions in the cortex and hippocampus.[5]
### Side-by-side studies
A few studies have examined both peptides as separate arms. In 52 healthy participants, resting-state fMRI showed both general and peptide-specific effects of Selank and Semax on functional connectivity between the right amygdala and the right temporal cortex, compared with placebo.[6] In rats with 6-OHDA-induced parkinsonism, neither peptide changed motor activity, while Selank reduced anxiety-like behavior.[7] An older review compared the anticoagulant activity of glyprolines, Semax and Selank.[8] A 2026 review grouped both with other neuroactive peptides that act on BDNF-related pathways, while noting a lack of clinical trials.[9]None of these studies administered the two peptides together, so any combined or additive effect remains untested.Because both peptides share a C-terminal Pro-Gly-Pro sequence, HPLC and mass-spectrometry certificates of analysis are the practical way to confirm each is present.

## Research Status

Neither Selank nor Semax is approved by the US FDA, and the combination has no clinical development program. Evidence for each component comes mostly from rodent and cell studies, plus one small human imaging study.[6]Selank has been tested alongside another compound: in rats under unpredictable chronic mild stress, anxiety measures after combined Selank and diazepam did not differ from pre-stress values, while Selank alone was the most effective at reducing drug-induced anxiety.[10] No comparable study pairs Selank with Semax. For the blend itself, there are no stability, pharmacokinetic or safety data.Supplier-made blends are sold for laboratory research use only. Because both components are short peptides that share a C-terminal sequence, each lot needs its own analytical characterization.

## FAQ

**What is in the Selank + Semax blend?**
The blend contains two synthetic heptapeptides: Selank, an analog of the immunomodulatory peptide tuftsin, and Semax, an analog of the ACTH(4-10) fragment. Both end in Pro-Gly-Pro. Suppliers commonly list it as 5 mg + 5 mg or 10 mg + 10 mg of material. It is a supplier-defined research formulation, not an approved product.

**Has the Selank and Semax combination been studied?**
Not as a combined formulation. Published research on the specific combination is limited. Selank and Semax have been compared as separate arms in a human fMRI study of 52 healthy participants and in a rat model of parkinsonism, but no study has given them together. Evidence for the blend comes from studies of each peptide alone.

**How is Selank different from Semax?**
Selank is built on tuftsin (Thr-Lys-Pro-Arg) and is studied as an anxiolytic, with gene-expression work pointing to the GABAergic system. Semax is built on ACTH(4-7) (Met-Glu-His-Phe) and is studied as a nootropic, with rat data showing increased BDNF in the basal forebrain. Both add the same Pro-Gly-Pro tail.

**Is the Selank + Semax blend FDA approved?**
No. Neither Selank nor Semax is approved by the US FDA, and the combination has no clinical development program. Most evidence for each peptide comes from rodent and cell studies. Supplier-made blends are sold for laboratory research use only.

## References

1. Volkova A, Shadrina M, Kolomin T, et al. Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission. Frontiers in pharmacology 2016. PMID: 26924987
2. Kolik LG, Nadorova AV, Antipova TA, et al. Selank, Peptide Analogue of Tuftsin, Protects Against Ethanol-Induced Memory Impairment by Regulating of BDNF Content in the Hippocampus and Prefrontal Cortex in Rats. Bulletin of experimental biology and medicine 2019. PMID: 31625062
3. Dolotov OV, Karpenko EA, Seredenina TS, et al. Semax, an analogue of adrenocorticotropin (4-10), binds specifically and increases levels of brain-derived neurotrophic factor protein in rat basal forebrain. Journal of neurochemistry 2006. PMID: 16635254
4. Tomasello MF, Di Rosa MC, Naletova I, et al. Semax, a Copper Chelator Peptide, Decreases the Cu(II)-Catalyzed ROS Production and Cytotoxicity of aβ by Metal Ion Stripping and Redox Silencing. Bioinorganic chemistry and applications 2025. PMID: 40496623
5. Radchenko AI, Kuzubova EV, Apostol AA, et al. The Potential of the Peptide Drug Semax and Its Derivative for Correcting Pathological Impairments in the Animal Model of Alzheimer's Disease. Acta naturae 2025. PMID: 41479572
6. Panikratova YR, Lebedeva IS, Sokolov OY, et al. Functional Connectomic Approach to Studying Selank and Semax Effects. Doklady biological sciences : proceedings of the Academy of Sciences of the USSR, Biological sciences sections 2020. PMID: 32342318
7. Slominsky PA, Shadrina MI, Kolomin TA, et al. Peptides semax and selank affect the behavior of rats with 6-OHDA induced PD-like parkinsonism. Doklady biological sciences : proceedings of the Academy of Sciences of the USSR, Biological sciences sections 2017. PMID: 28702721
8. Liapina LA, Pastorova VE, Obergan TIu, et al. [Comparison of anticoagulant effects of regulatory proline-containing oligopeptides. Specificity of glyprolines, semax, and selank and potential of their practical application]. Izvestiia Akademii nauk. Seriia biologicheskaia 2006. PMID: 16634437
9. Rahman OF, Lee SJ, Seeds WA. Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions. Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews 2026. PMID: 41490200
10. Kasian A, Kolomin T, Andreeva L, et al. Peptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Unpredictable Chronic Mild Stress Conditions in Rats. Behavioural neurology 2017. PMID: 28280289