Vial duration

Semax vial duration calculator

Estimate how many weeks one 5 mg Semax 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

1.7 weeks

Semax weeks-of-supply at common cadences

How long one 5 mg Semax vial covers at a 0.4 mg per dose, for three weekly cadences. Total doses per vial: 12.

Doses per week	Total doses per vial	Weeks of supply
6	12	2.0
7	12	1.7
8	12	1.5

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 Semax vial lasts, the long version

Total doses in the vial: floor(5 ÷ 0.4) = 12. The floor matters — a partial dose at the bottom doesn't count.
Cadence: 7 doses per week for Semax at this example step.
Math weeks-of-supply: 12 ÷ 7 = 1.7 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 Semax

Math says one 5 mg Semax vial covers 1.7 weeks at 0.4 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

Semax next to Selank

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

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

Want the full breakdown? Selank reference →

Semax is a synthetic peptide that people use to support cognitive functions like memory and focus. It’s a modified piece of a naturally occurring hormone, but it’s designed to work primarily in the brain. Research in its country of origin, Russia, has explored its use in recovery from conditions like stroke, though data from large-scale international trials is limited. This page covers what Semax is, how it’s thought to work, and the common ways people track its use in research settings for brain health and mental performance.

Planning Semax vials in real life

Semax vial planning depends heavily on dose step. A 5 mg vial at 400 mcg lasts 12 days; at 1000 mcg it lasts 5 days. The wide dose range — researchers and personal-tracking users run anywhere from 300 mcg to 1000 mcg — means vial-per-cycle counts can vary 3x. Pin your dose step before ordering.

Stability is generous relative to vial life at any dose step. The 4-6 week reconstituted window is longer than any single Semax vial lasts at daily cadence, so stability is never the binding constraint. The constraint is supply. Higher-dose users (600-1000 mcg) running 4-week cycles need 4+ vials per cycle — order in batches.

Storage and shelf life for Semax

Proper storage is absolutely critical to preserve the potency and integrity of your Semax. Before reconstitution, the peptide exists as a lyophilized powder in a vial. In this state, it is relatively stable but should still be protected from heat and light. For long-term storage, keeping the unopened vials in a freezer at around -20°C (-4°F) is the best practice. This can preserve the peptide for a year or even longer. If you plan to use the vial within a few months, storing it in a standard refrigerator at 2°C to 8°C (36°F to 46°F) is sufficient. The key is to avoid temperature fluctuations and keep it away from the kitchen counter or any place where it might be exposed to sunlight or high heat, which can rapidly degrade the delicate peptide chains.

Once you have reconstituted the Semax powder with bacteriostatic water, the storage rules change. The liquid solution is much less stable and must be kept in the refrigerator at all times. Never freeze Semax *after* it has been mixed, as the freeze-thaw cycle can damage the peptide molecules and render them ineffective. A reconstituted vial of Semax is typically good for about 20 to 30 days when stored properly in the fridge. It’s important to always check the solution for any signs of cloudiness or discoloration before each use, as this could indicate contamination or degradation. For those using the pre-made nasal spray versions, the storage instructions are similar: keep the bottle refrigerated and pay close attention to the expiration date provided by the manufacturer to ensure you are using a potent and stable product.

How the Semax vial duration calculator works

A 5 mg Semax vial covers 12 doses at 400 mcg — about 2 weeks at daily cadence. Step up to 1000 mcg and the vial covers 5 days. Plan 1-3 vials per 2-4 week cognitive cycle depending on dose step.

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 Semax, a 0.4 mg dose, and 7 dose per week, the vial covers 12 doses, or about 1.7 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.

The "Vial Duration" calculator is your planning assistant, designed to answer the practical question: "How long will my vial of Semax last?" This tool takes the total amount of peptide in your vial (e.g., 5 mg), your planned daily dose (e.g., 0.4 mg), and how many doses you take per week (e.g., 7) to project an end date for your supply. For instance, with a 5 mg vial and a 0.4 mg daily dose, the calculator will show that the vial contains about 12 full doses. If you’re dosing every day, that means you have just under two weeks of supply from that single vial. This information is invaluable for managing your research budget and schedule.

This foresight is especially important when you are considering changes to your protocol. Let's say you are halfway through a cycle and decide to titrate your dose upward from 0.4 mg to 0.5 mg to see if it enhances the effects. The Vial Duration calculator will immediately update its projection, showing you that your remaining supply will now run out sooner than you originally thought. This allows you to plan your next purchase accordingly, preventing any unwanted gaps in your protocol. Running out of a peptide unexpectedly can disrupt your research, and this tool is your best defense against that.

Moreover, using the Vial Duration calculator helps you manage your inventory effectively, especially if you buy peptides in advance. By knowing how long each vial will last under different dosing scenarios, you can ensure you are using your oldest reconstituted vials first and that your unopened, long-term storage vials are properly cataloged. It brings a level of logistical organization to your research that supports consistency and reduces stress. You can experiment with different dosing schedules in the calculator to see how they impact your supply, making it a powerful tool for long-term cycle planning.

Common Semax vial-planning mistakes

Storing the reconstituted vial at room temperature instead of in the refrigerator.
Shaking the vial vigorously during reconstitution, which can damage the peptide.

Frequently asked questions about Semax vial duration

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

It floors total doses (vial mg ÷ dose mg) then divides by doses per week. For this Semax example — a 5 mg vial, 0.4 mg per dose, 7 dose/week — that's floor(5 ÷ 0.4) ÷ 7 = about 1.7 weeks. Flooring matters: a partial dose left in the vial doesn't count. Higher Semax doses (600-1000 mcg) burn vials in under a week — order ahead for higher-dose cycles.

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

Whichever runs out first. Math says Semax 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. Higher Semax doses (600-1000 mcg) burn vials in under a week — order ahead for higher-dose cycles.

Does titrating the Semax 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. Higher Semax doses (600-1000 mcg) burn vials in under a week — order ahead for higher-dose cycles.

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

Drop the doses-per-week field. With 7 dose/week the example vial lasts about 1.7 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. Higher Semax doses (600-1000 mcg) burn vials in under a week — order ahead for higher-dose cycles.

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