What Is Selank? Dosage, Half-Life & How to Track It
Also known as: Selank Peptide · Tuftsin Analog Heptapeptide · TKPRPGP
Selank is a synthetic heptapeptide analog of tuftsin studied for anxiolytic (anxiety-reducing) and anti-asthenic (fatigue-reducing) effects. Subcutaneous protocols run 300–500 mcg once daily, titrated up over the first two weeks and commonly cycled 4 weeks on / 4 weeks off to limit tolerance. Its measured half-life is only a few minutes, though clinical trials have used it continuously for up to 14 days with good tolerability. Educational information only — not a substitute for a prescriber’s guidance.
What Selank is and how it works
Selank is a synthetic heptapeptide — a lab-made analog of tuftsin, an immune-signaling peptide the body produces naturally. It was developed in Russia and, unlike most peptides in this library, has been studied specifically for mood and cognition rather than physical tissue repair: anxiolytic (anti-anxiety) and anti-asthenic (anti-fatigue) effects.
In Russian clinical research, intranasal Selank produced anxiety relief that investigators compared to benzodiazepines — without the sedation or dependence risk those drugs carry. The proposed mechanism touches several systems at once: it appears to modulate GABA and serotonin signaling, influence BDNF expression (the same growth factor tied to neuroplasticity), and support more balanced cortisol output under stress.
Worth being direct about the evidence: the strongest data is intranasal, using a formulation sold in Russia and not widely available elsewhere. The subcutaneous dosing below is a community adaptation for people using research-peptide vials rather than the studied nasal spray, and rigorous data outside Russia is still thin.
Typical dosing & reconstitution
Selank ships as a lyophilized powder and is reconstituted with bacteriostatic water. Subcutaneous protocols typically run 300–500 mcg once daily, starting at the low end for the first two weeks. Because tolerance (tachyphylaxis) can build with continuous exposure, a common pattern is 4 weeks on, 4 weeks off — or 5 days on with a 2-day break each week.
Two common reconstitution setups:
| Vial | BAC water | Concentration | 1 unit (U-100) ≈ |
|---|---|---|---|
| 5 mg | 3 mL | 1.67 mg/mL | 16.7 mcg |
| 10 mg | 3 mL | 3.33 mg/mL | 33.3 mcg |
At 1.67 mg/mL, a 300 mcg dose is 18 units on a standard U-100 insulin syringe. The reconstitution calculator does this math for whatever vial and water amount you actually have.
Half-life & what it means for frequency
Selank’s parent peptide is broken down quickly in the bloodstream — published estimates put its measurable half-life at only a few minutes. That sounds like it should demand hourly dosing, but the practical picture is different: as Selank degrades, some of its breakdown fragments remain biologically active, which is thought to extend its functional effect well past the parent molecule’s presence in blood.
That is also why once-daily dosing is the norm rather than something split across the day, and why the on/off cycling pattern matters more for Selank than within-day timing does — the tolerance risk builds from continuous daily exposure, not from any single dose lingering too long.
What to track & common side effects
Selank is generally reported as well tolerated, with the most common complaints being mild injection-site irritation and occasional drowsiness shortly after a dose. Formal safety data is limited to short clinical courses (up to 14 days), so longer real-world use is less studied.
What is worth tracking here differs from a healing peptide: not a wound or injury, but subjective anxiety, fatigue, and energy day to day, alongside the dose and where you are in the on/off cycle — exactly the kind of pattern that is easy to lose without a log.
How to track Selank in Stackeddd
Log each Selank dose and where you are in the 4-weeks-on/4-weeks-off cycle, so continuous tolerance-building use never happens by accident. Track mood, anxiety, or energy alongside it to see whether the pattern is actually doing something. Run the reconstitution once so 300 mcg is really 300 mcg.
Model it yourself · free, no account
Reconstitution Calculator
Model it yourself: enter your vial size and how much BAC water you added, and the Peptides tab returns the concentration and the exact insulin-syringe units for any dose — the same math built into the Stackeddd app.
Related compounds
Related reading: Peptide reconstitution math: how much BAC water to add · What peptides can you mix in the same syringe?
Frequently asked questions
What is Selank used for?
Selank is studied primarily as an anxiolytic (anti-anxiety) and anti-asthenic (anti-fatigue) peptide. Russian clinical research found intranasal Selank comparable to benzodiazepines for anxiety relief without sedation or dependence risk. It is not FDA-approved for human use.
What is the half-life of Selank?
Only a few minutes in the bloodstream — but active breakdown fragments are thought to extend its practical effect well past that window, which is why it is still dosed once daily rather than continuously.
How long can you take Selank continuously?
Clinical studies have used it for up to 14 days of continuous dosing with good tolerability. Community protocols commonly cycle 4 weeks on, 4 weeks off (or 5 days on, 2 off each week) to limit tolerance building.
Is Selank the same as Semax?
No — related research family, different job. Semax targets cognition and neuroprotection; Selank targets anxiety and fatigue. Some protocols stack them, but they are distinct peptides with different mechanisms.
This is educational information, not medical advice. Doses and protocols above reflect published references and community practice — protocol decisions belong with your prescribing physician. Generic names used throughout. How this reference is built & how the AI is tested →
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