Semax 5 mg Vial: Reconstitution and Dosing Chart

How much bacteriostatic water to add to a 5 mg vial of Semax, the concentration you get, and a full dose-to-units chart.

Medical review pendingACTH(4-10) analogUpdated 21 Oct 2026

Vial size: 5 mg
With 2 mL water: 2.5 mg/mL; common choice
10 units contain: 250 mcg; at 2 mL, U-100
Whole vial: 200 units; 2 mL on a U-100 scale

How much water to add

Bacteriostatic water only changes the concentration, not the amount of Semax in the vial. More water means more units per dose (easier to read), less water means fewer.

Semax 5 mg vial: concentration by water added
Water added	Concentration	10 units contain	100 mcg is	Whole vial
1 mL	5 mg/mL	500 mcg	2 u	100 u
2 mL	2.5 mg/mL	250 mcg	4 u	200 u
2.5 mL	2 mg/mL	200 mcg	5 u	250 u
3 mL	1.667 mg/mL	166.7 mcg	6 u	300 u

Calculator and full dosing table

Preset to the 5 mg vial. Change any value; the table below the result updates with it.

1Vial size

2Bacteriostatic water added

3Dose per injection

4Syringe (U-100)

Draw to

20units

= 0.2 mL on a 1 mL U-100 insulin syringe

5 mg vial2 mL water500 mcg dose

Concentration: 2.5 mg/mL
Doses per vial: 10
Weeks (1 dose/wk): 10

Math only. It does not recommend a dose.

Dosing table for a 5 mg vial

Syringe units (U-100) for each dose, by how much bacteriostatic water you add.

Semax: U-100 syringe units per dose for a 5 mg vial
Dose	1 mL water	2 mL water	2.5 mL water	3 mL water
100 mcg	2	4	5	6
250 mcg	5	10	12.5	15
300 mcg	6	12	15	18
500 mcg	10	20	25	30
750 mcg	15	30	37.5	45
1000 mcg	20	40	50	60

How the math works

Concentration is the vial's milligrams divided by the water you add. Volume to draw is your dose divided by that concentration. On a U-100 syringe, 1 mL is 100 units, so units = mL × 100.

5 mg ÷ 2 mL = 2.5 mg/mL
500 mcg = 0.5 mg; 0.5 mg ÷ 2.5 mg/mL = 0.2 mL
0.2 mL × 100 = 20 units

20 units · 0.2 mL · 500 mcg from 5 mg + 2 mL

Math only. The amounts in these tables are reference values for the arithmetic, not dose recommendations.

Where the semax amounts for a 5 mg vial come from

In a trial of patients after ischemic stroke, the standard semax regimen was 2 courses at 6000 mcg/day; the abstract does not state the route.^[3]

Rats with a toxin-induced brain lesion received intranasal semax at 0.2 mg/kg daily, a per-kg animal dose that is not converted.^[4]

What a 5 mg semax vial gives

Mixed with 1, 2 or 3 mL of water, a 5 mg semax vial is 5, 2.5 or 1.667 mg/mL, so one U-100 unit holds 50, 25 or 16.667 mcg.

Calculated from vial mg 5; water mL 1, 2, 3; u100 units per mL 100. Formula: mg/mL = vialMg / waterMl; mcg per unit = mg/mL x 10

A 5 mg semax vial holds 5000 mcg in total, which is 50 mcg per unit if mixed to 1 mL and 16.667 mcg per unit if mixed to 3 mL.

Calculated from vial mg 5. Formula: mcg = vialMg x 1000; per unit = mcg / (100 x mL)

Is 5 mg a labelled semax strength?

Drugs@FDA returns the message "No matches found!" for semax, so there is no FDA-labelled semax strength.^[5]

With 0 matching applications in Drugs@FDA there is no labelled strength to compare a 5 mg semax vial with.

Calculated from vial mg 5; drugs fda matches 0; source s2-legal/api.fda.gov/drugsfda-semax.txt. Formula: labelled strengths available = 0

Common questions

How much water goes in a 5 mg vial of Semax?

That choice only changes the concentration. With 2 mL, a 5 mg vial is 2.5 mg/mL; with 1 mL it is 5 mg/mL. Less water means fewer units per dose and harder-to-read marks for small doses.

How many units is 100 mcg from a 5 mg vial?

With 2 mL of water, 100 mcg is 4 units on a U-100 syringe. With other water amounts, see the table.

How many doses are in a 5 mg vial?

Divide the vial size by the dose (in the same unit). The calculator on this page shows the number of whole doses for any dose you pick.

How much bacteriostatic water for a 5mg semax vial?

The water volume only sets the strength: 5 mg of semax in 1, 2 or 3 mL is 5, 2.5 or 1.667 mg/mL, which is 50, 25 or 16.667 mcg per syringe unit.

Calculated from vial mg 5; water mL 1, 2, 3. Formula: mg/mL = vialMg / waterMl; mcg per unit = mg/mL x 10

More on Semax

DosageDoses used in published studies, with the source for each.CalculatorVial, water and dose to syringe units.Side effectsWhat labels and studies report, and what is unknown.BenefitsClaimed benefits next to what published studies measured.How it worksTarget, mechanism and how long it acts, from the label or studies.Nasal sprayStudies that gave Semax as nasal spray, and what is approved.

Sources

1Metric (SI) Prefixes (NIST Reference on Constants, Units, and Uncertainty)National Institute of Standards and Technology (NIST) · 2025physics.nist.govAccessed 2 Oct 2026
2BASAGLAR (insulin glargine) injection, prescribing information (DailyMed)U.S. Food and Drug Administration / DailyMed (Eli Lilly and Company label) · 2026dailymed.nlm.nih.govAccessed 2 Oct 2026
3[The efficacy of semax in the tretament of patients at different stages of ischemic stroke].Zhurnal nevrologii i psikhiatrii imeni S.S. Korsakova · 2018PMID 29798983Accessed 2 Oct 2026
4The neuroprotective effects of Semax in conditions of MPTP-induced lesions of the brain dopaminergic system.Neuroscience and behavioral physiology · 2004PMID 15341218Accessed 2 Oct 2026
5Drugs@FDA (openFDA) search: active ingredient "semax"U.S. Food and Drug Administration · 2026api.fda.govAccessed 2 Oct 2026

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