Vial duration

Selank vial duration calculator

Estimate how many weeks one 5 mg Selank vial covers at your dose and weekly cadence.

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Last updated: May 13, 2026

Vial (mg)

Dose (mg)

Doses / week

Total doses

Lasts

2.3 weeks

Selank weeks-of-supply at common cadences

How long one 5 mg Selank vial covers at a 0.3 mg per dose, for three weekly cadences. Total doses per vial: 16.

Doses per week	Total doses per vial	Weeks of supply
6	16	2.7
7	16	2.3
8	16	2.0

Math weeks-of-supply assumes every dose draws cleanly. Stability typically caps a reconstituted vial at 4–6 weeks of refrigerated use regardless of how much liquid remains.

Worked example

How long one Selank vial lasts, the long version

Total doses in the vial: floor(5 ÷ 0.3) = 16. The floor matters — a partial dose at the bottom doesn't count.
Cadence: 7 doses per week for Selank at this example step.
Math weeks-of-supply: 16 ÷ 7 = 2.3 weeks of liquid in the vial.
Stability ceiling: most reconstituted peptides are typically used within 4–6 weeks of refrigerated storage. Whichever number is smaller is the one that binds your refill date.
Doubling the dose roughly halves both numbers — and titration usually closes the gap between "math weeks" and "stability weeks" without you noticing.

Scenarios people actually run into

Three things that come up logging Selank

Math says one 5 mg Selank vial covers 2.3 weeks at 0.3 mg per dose. Stability typically caps a reconstituted vial at 4–6 weeks. Whichever number is smaller is the date on your refill calendar.
Titration up doubles the dose and halves the vial. A 12-week-on-paper vial becomes a 6-week vial the day you step up — order the next vial the same day you take the step.
Shipping windows are the silent third constraint. If your supplier runs 1–3 weeks, the refill order has to leave at least that long before "math weeks" or "stability weeks," whichever is binding.

Same-category neighbor

Selank next to Semax

Both sit in the Cognitive bucket — here's the vial duration math side by side on each one's example vial.

	Selank	Semax
Vial	5 mg	5 mg
Cadence	7/wk	7/wk
Weeks of supply	2.3	1.7

Want the full breakdown? Semax reference →

Selank is a peptide that people explore for its potential effects on anxiety and brain function, often talked about in nootropic circles. It is a synthetic version of a natural peptide found in the spleen called tuftsin, but with a more stable structure that allows it to last longer in the body. Early-stage studies have reported its influence on the balance of certain brain chemicals and proteins involved in nerve growth, which may be linked to mood, learning, and stress resilience. This page covers what the research says about Selank, common ways people track it, and how to use the app’s calculators to stay organized.

Planning Selank vials in real life

Selank vial planning is dictated by cycle length, which tends to be short. A 5 mg vial at 300 mcg daily covers 16 doses — about 2 weeks. A typical 2-week cognitive cycle uses 1 vial; a 4-week cycle uses 2. The math is linear and the cycles are short enough that stability is never a constraint.

If you're running back-to-back cycles, reconstitute a fresh vial at each cycle start rather than carrying a half-vial through an off-week. Selank's 4-6 week stability window is generous on paper but the practical pattern is 'one cycle, one or two vials, then fresh' — that's how most disciplined cognitive-protocol users work.

Storage and shelf life for Selank

Proper storage of Selank is essential to maintain its potency and integrity. Before reconstitution, the lyophilized (freeze-dried) powder is relatively stable. For long-term storage, it should be kept in a freezer, ideally below -20°C (-4°F). This can preserve its quality for a year or longer. For shorter-term storage, keeping the unopened vial in a refrigerator (between 2°C and 8°C or 36°F and 46°F) is also acceptable, where it should remain stable for several months. It

s crucial to protect the powder from light and heat, so always keep the vial in its box or a dark container. Exposure to room temperature for brief periods, such as during shipping, is generally not a major issue, but prolonged exposure should be avoided. The key is to keep it cold and dark until you are ready to mix it.

How the Selank vial duration calculator works

A 5 mg Selank vial covers 16 doses at 300 mcg — about 2 weeks at daily cadence. Most Selank cognitive cycles are 2-4 weeks, so plan 1-2 vials per cycle. Stability gives plenty of margin at this short cycle length.

The formula is two divisions. Total doses per vial equals vial mg divided by dose mg, rounded down. Weeks of supply equals total doses divided by doses per week. With a 5 mg vial of Selank, a 0.3 mg dose, and 7 dose per week, the vial covers 16 doses, or about 2.3 weeks of supply.

The three inputs that move the answer: vial mg (set when you bought the vial), dose mg (set by your protocol step), and doses-per-week (set by the peptide's half-life). Once a vial is reconstituted it also has a stability ceiling — most lyophilized peptides reconstituted in BAC water are typically used within four to six weeks of refrigerated storage, so a vial that mathematically lasts twelve weeks may not last twelve weeks in practice.

One of the most practical questions when starting a peptide protocol is, "How long will my vial last?" The Vial Duration Calculator is designed to give you a clear answer, helping you plan your cycles and supplies. This tool takes your vial’s total peptide amount, your planned daily dose, and tells you how many doses you can expect to get from a single vial. For instance, you have a 5 mg vial of Selank and you plan to take 0.3 mg each day. By entering these numbers, the calculator will instantly show you that the vial contains approximately 16 doses. This lets you know that one vial will be sufficient for a standard 14-day cycle, with a little bit extra to spare.

This calculator is also incredibly useful for understanding the impact of any dose adjustments you might make. Let's say you start your Selank cycle at 0.3 mg per day, which gives you 16 days of use from your 5 mg vial. However, after a week, you decide to increase your dose to 0.5 mg daily to see if it enhances the calming effects you're tracking. The calculator can show you that at this new dose, your remaining peptide will last for fewer days. This foresight is crucial for planning. It helps you decide if you need to acquire more supplies to complete your intended cycle, preventing you from running out unexpectedly midway through.

By planning ahead, you can ensure you follow your protocol without interruption. If you know you get 16 doses of 0.3 mg from your vial, and you plan to run a "14 days on, 21 days off" cycle, you know that one vial perfectly covers your "on" period. If your protocol involved a higher dose or more frequent administration, you might see that a single vial isn't enough. The Vial Duration Calculator provides the clarity needed to budget and schedule your peptide use effectively, removing logistical stress so you can focus on tracking your experience.

Common Selank vial-planning mistakes

Storing the mixed solution at room temperature instead of in the refrigerator.
Shaking the vial vigorously after adding water, which can damage the peptide.

Frequently asked questions about Selank vial duration

How does the Selank vial duration calculator estimate weeks of supply?

It floors total doses (vial mg ÷ dose mg) then divides by doses per week. For this Selank example — a 5 mg vial, 0.3 mg per dose, 7 dose/week — that's floor(5 ÷ 0.3) ÷ 7 = about 2.3 weeks. Flooring matters: a partial dose left in the vial doesn't count. Short Selank cycles (2-4 weeks) finish well inside stability — no leftover, no waste.

Should I plan refills around the math, or around stability?

Whichever runs out first. Math says Selank at the example dose lasts the calendar weeks shown above. Stability says most reconstituted peptides are typically used within 4–6 weeks of refrigerated storage regardless of how much liquid is left. If the math says 12 weeks but stability caps at 5, plan around 5 — and reconstitute the next vial with less water so you finish it in the stability window. Short Selank cycles (2-4 weeks) finish well inside stability — no leftover, no waste.

Does titrating the Selank dose up shorten vial life?

Yes, often dramatically. Doubling the dose halves the doses-per-vial. The calculator shows real-time how a step-up changes the weeks-of-supply line, so you can re-time refill orders before a titration event rather than discovering the gap mid-protocol. Short Selank cycles (2-4 weeks) finish well inside stability — no leftover, no waste.

What if I take Selank less often than the default cadence here?

Drop the doses-per-week field. With 7 dose/week the example vial lasts about 2.3 weeks; halving the cadence roughly doubles that, but you'll hit the stability ceiling first. A vial that mathematically covers 16 weeks rarely covers 16 weeks in practice. Short Selank cycles (2-4 weeks) finish well inside stability — no leftover, no waste.

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