Selank: Reference Overview and Reconstitution Notes

Selank is a man-made peptide, which is a short chain of amino acid building blocks. It is based on a natural compound called tuftsin. Researchers study it for possible effects on thinking and mood. It is not approved by the FDA. In the United States it is for research use only. Russia has approved it as an anti-anxiety drug.

Selank

What it is

Selank is a man-made peptide made of seven amino acids (the building blocks of proteins). Its amino acid sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was built from tuftsin, a natural peptide that comes from a larger immune protein called immunoglobulin G.

Scientists added extra amino acids to the tuftsin chain to slow it from being broken down. Think of it like adding more links to a chain so it holds together longer. This change gives Selank greater metabolic stability (the ability to resist being broken down) than the original tuftsin.

Research context and categorization

Selank is grouped with peptides studied for possible effects on thinking and mood. Because it comes from tuftsin, it also has ties to the immune system. Immunomodulatory simply means it may affect how the immune system works.

It was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences together with the V.V. Zakusov Research Institute of Pharmacology.

Anxiety and Cognitive Research

Researchers commonly study Selank in relation to anxiety and stress. They also look at possible effects on thinking and attention.

It is studied in connection with two chemical signaling systems in the brain. One is the GABAergic system (GABA is a chemical that helps calm nerve activity). The other is the monoaminergic system (monoamines are chemicals like dopamine and serotonin that affect mood). Researchers also track changes in cytokines and interleukins, which are small proteins the immune system uses to send signals. This connects back to Selank's roots in tuftsin.

Approval and Evidence Limitations

Outside of Russia, these research areas are still under investigation. In the United States and most other countries, none of these uses are confirmed or approved.

Most of the existing research comes from Russian institutions. There is currently limited independent international replication of these findings, meaning scientists in other countries have not yet widely repeated or confirmed the results.

Status

• Regulatory status: Not FDA-approved in the United States, where it is for research use only and is investigational. As of 2026, the FDA has listed it as a Category 2 bulk drug substance. This means compounding pharmacies (specialized pharmacies that mix custom preparations) cannot use it while the FDA's review is still ongoing. Selank is approved in Russia and some neighboring countries as a prescription or over-the-counter anti-anxiety drug.
• Sport status: Selank is not listed by name on the WADA Prohibited List. WADA is the World Anti-Doping Agency, the organization that sets rules about banned substances in sport. However, because Selank is not approved by major Western health regulators for human therapeutic use, it may fall under the S0 Non-Approved Substances category, a catch-all rule that covers unapproved substances. Athletes subject to testing should treat it with caution.

Key point: Selank is not FDA-approved in the United States. It remains restricted to investigational research and is classified as a Category 2 bulk drug substance.

Reconstitution notes (general)

Lyophilized peptides come as a freeze-dried powder in a vial. To prepare them for research, you add bacteriostatic water, which is a sterile water containing a small amount of preservative. Concentration means how much peptide is in each milliliter of liquid. You find it by dividing the milligrams in the vial by the milliliters of water you add. Common examples:

• 5 mg in 2 mL gives 2.5 mg/mL
• 10 mg in 2 mL gives 5 mg/mL

You can work out volumes and concentrations with the calculator at peptide calculator.

Dilution and handling notes (compound-specific)

Selank is a short peptide that dissolves easily in water. Common reference concentrations used in research fall in the range of about 1 to 5 mg/mL.

Reconstitution Ratios

Researchers commonly use the following dilutions as reference points:

• 5 mg vial: Reconstituted with 2 to 3 mL of bacteriostatic water (roughly 2.5 mg/mL down to about 1.67 mg/mL).
• 10 mg vial: Reconstituted with 2 to 3 mL of bacteriostatic water (about 5 mg/mL down to roughly 3.33 mg/mL).

Using lower concentrations can make small, measured volumes easier to read during evaluations.

Mixing Best Practices

Because Selank dissolves easily, it does not tend to clump or form a stubborn gel the way some longer or greasier peptides do. It can still foam, though, if water is added too quickly.

Add the bacteriostatic water slowly, letting it run down the inside wall of the vial rather than squirting it straight onto the powder. Then swirl or gently roll the vial. Do not shake it.

Shaking pulls air into the liquid and creates foam, which can stress and degrade the peptide. The finished solution should be clear and colorless.

Note that in its Russian clinical form, Selank is used as an intranasal spray (a spray delivered into the nose) rather than as an injectable. Reconstitution practices will vary depending on the research format being used.

Handling and storage

Store reconstituted Selank in a refrigerator at 2 to 8 C and keep it away from direct light. Before drawing from the vial, wipe the rubber stopper with an alcohol swab. Label the vial with the date you mixed it.

A reconstituted solution is generally referenced with about a 4-week usable window when kept refrigerated.

Discard the vial if the liquid turns cloudy or changes color, or if you see any floating particles.

Related reading

• Semax
• Sermorelin
• SLU-PP-332
• How Reconstitution Works
• How Long Does a Reconstituted Vial Last?

Tools and supplies

• peptide calculator
• Bacteriostatic Water 30 ml
• Gansulin Metal Reusable Pen
• 3 ml Glass Cartridges (10-pack)
• Complete Starter Kit

Reminder: research and educational reference only. Preppin Peppers sells hardware and materials, not peptides. Not medical, dosing, or health advice, not evaluated by the FDA, and not intended for human or animal use.

Frequently asked questions

What is Selank's regulatory status in the United States?

Selank is not FDA-approved in the US and is classified as a Category 2 bulk drug substance as of 2026, prohibiting compounding pharmacy use while FDA review is ongoing; it is restricted to investigational research only.

What is the amino acid sequence of Selank?

Selank's sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a 7-residue synthetic peptide derived from tuftsin, with additional amino acids incorporated to improve metabolic stability compared to the parent compound.

Is Selank listed on the WADA Prohibited List?

Selank is not listed by name on the WADA Prohibited List, but as an unapproved substance it may fall under the S0 Non-Approved Substances catch-all category; athletes subject to doping controls should treat it with caution.

What the research community gets wrong about Selank

Selank shows up in a lot of bench notes, and a few ideas get passed around that do not hold up. Here are the ones worth correcting.

• Selank is not just tuftsin. It is a seven-amino-acid sequence (Thr-Lys-Pro-Arg-Pro-Gly-Pro) built from tuftsin with extra residues added to resist breakdown. Data collected on one should not be assumed to carry over to the other.
• "Easy to dissolve" gets read as "hard to damage." Selank mixes into water without clumping, but that does not make the solution tough. Adding water too fast or shaking the vial pulls in air and creates foam, and the air and liquid interface can stress the peptide.
• Most published work comes from a small group of labs. A finding being "in the literature" is not the same as it being repeated widely. Much of the Selank record traces back to a few Russian institutions, so treat single-source results as starting points, not settled facts.
• The studied format is not always an injectable. The approved Russian product is an intranasal spray, so handling and storage notes copied from injectable peptides may not match the form a given paper actually used. Check what format the source describes before comparing.
• "Research use only" describes legal status, not what is in the vial. That label says nothing about purity or identity. Only testing confirms what a powder actually is.

From our bench: If you have reconstituted a Selank vial, we would like your real handling notes. Tell us the vial size and the volume of bacteriostatic water you added, how you added it (slow down the wall versus straight onto the powder), and whether the solution went clear and colorless or foamed. Also note how many days it stayed clear in the refrigerator before you saw any cloudiness or particles. Please share only what you actually measured or observed, with no rounded-off guesses.

Sources

1. Bacteriostatic Water for Injection, USP , FDA/DailyMed label (0.9% benzyl alcohol)
2. Duerkop et al., Biotechnol J 2018 , Impact of Cavitation, High Shear Stress and Air/Liquid Interfaces on Protein Aggregation
3. Sigma-Aldrich (Merck) , Handling and Storage Guidelines for Peptides and Proteins
4. Selank (PubChem CID 11765600) , compound record, molecular formula C33H57N11O9
5. Filatova E. et al., Front. Pharmacol. 2017 , GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells
6. Konstantinopolsky M.A. et al., Bull. Exp. Biol. Med. 2022 , Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats