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How Much Bacteriostatic Water for Semax? 5 mg and 10 mg Vials

RESEARCH USE ONLY. This page contains unit-conversion arithmetic only. It is not a dosing guide, not a protocol, and not a preparation or administration instruction for any person or animal. Products discussed on this site are supplied strictly for laboratory and research purposes.

Semax is sold in two vial sizes. The tables below convert vial mass and solvent volume into concentration — nothing more. Choosing a volume is a measurement decision, not a protocol.

Semax and Selank are separate vials and separate arithmetic

These two are frequently ordered together and frequently mixed up once the labels are off. They are different compounds in different vials, each with its own label mass. A concentration worked out for one tells you nothing about the other. If you have both, run the Selank numbers separately.

5 mg vial

Bacteriostatic water added Concentration Contained in 10 units Contained in 20 units
1 mL 5 mg/mL 0.5 mg 1 mg
2 mL 2.5 mg/mL 0.25 mg 0.5 mg
3 mL 1.67 mg/mL 0.167 mg 0.333 mg
5 mL 1 mg/mL 0.1 mg 0.2 mg

10 mg vial

Bacteriostatic water added Concentration Contained in 10 units Contained in 20 units
1 mL 10 mg/mL 1 mg 2 mg
2 mL 5 mg/mL 0.5 mg 1 mg
3 mL 3.33 mg/mL 0.333 mg 0.667 mg
5 mL 2 mg/mL 0.2 mg 0.4 mg

Worked example: a 10 mg vial reconstituted with 2 mL gives 5 mg/mL. Twenty units is 0.2 mL. 0.2 mL × 5 mg/mL = 1 mg.

The syringe unit point almost every page gets wrong

An insulin syringe is graduated in units, which are a volume marking, not a mass. On both U-100 and U-50 insulin syringes, one unit corresponds to 0.01 mL. The difference is barrel capacity and gradation spacing — not the unit-to-volume relationship. A U-50 holds 0.5 mL across 50 units; a U-100 holds 1.0 mL across 100 units. Both are 100 units per millilitre.

The arithmetic is: mass = (peptide mg ÷ mL of solvent added) × (units × 0.01)

Our reconstitution calculator runs this across a 44-compound library if you would rather not do it by hand.

What limits how long the solution lasts

Sourced fact: The Bacteriostatic Water for Injection label directs: “Do not store reconstituted solutions of drugs for injection unless otherwise directed by the manufacturer of the solute.” The same label describes the product as supplied in “a multiple-dose container from which repeated withdrawals may be made to dilute or dissolve drugs for injection,” preserved with 0.9% or 1.1% benzyl alcohol. [1]

Inference: The widely-quoted 28-day figure describes the multiple-dose container of water, not what you dissolved in it. We traced that rule to its actual source — it is not printed on the FDA label at all — in where the 28-day rule actually comes from.

What this page is not

This is unit-conversion arithmetic for laboratory research planning. It is not medical or veterinary advice, not a protocol, not a recommendation of any volume, and not an instruction to administer anything to any person or animal. Semax is not approved by the FDA for human or veterinary use.

Reconstitution arithmetic for every compound in the catalogue: BPC-157 · TB-500 · Wolverine Stack · GLOW · KLOW · CJC-1295 / Ipamorelin · Ipamorelin · CJC-1295 No DAC · GHK-Cu · Epitalon · MOTS-c · AOD-9604 · NAD+ · PT-141 · Tesamorelin · Retatrutide · Tirzepatide · SS-31 · Selank · Semax · KPV · DSIP · PEG-MGF · FOXO4-DRI · ARA-290 · 5-Amino-1MQ

For researchers

Semax · Bacteriostatic Water, USP · Reconstitution calculator · Reconstitution handling guide · Selank arithmetic

BPC-157 is currently the only compound in our catalogue with completed third-party COA figures published on its page — lot 3CDMQXU, chromatographic purity >99.95%, 99.2% of stated label claim, identity confirmed by HPLC-UV-MS, tested by Krause Analytical. Every other product page, including this one, states plainly that its certificate is pending.


RESEARCH USE ONLY — FULL DISCLAIMER. The products discussed on this page are supplied strictly for laboratory and scientific research purposes. They are not for human or veterinary use, and not for consumption. These statements have not been evaluated by the Food and Drug Administration. Nothing on this page is intended to diagnose, treat, cure, or prevent any disease in humans or animals. Nothing here constitutes medical or veterinary advice or a dosing, preparation, or administration recommendation for any person or animal.

References

  1. Hospira, Inc. Bacteriostatic Water for Injection, USP — SPL Set ID 87d6e9dc-fe3b-4593-ac9a-d7493d1959c7, label updated 22 May 2026, version 20. NLM DailyMed.
  2. Vial sizes quoted from the PureLab Performance Semax product specification, verified 20 August 2026.
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