Buy Semax Nasal Spray: $3.00/mg Buys a Vial, Not a Bottle

Put the two formats in one table and the units stop matching almost immediately, which is the whole reason price comparisons between them go wrong.

Say plainly what this listing is: a dry vial, sold as laboratory research material, not a spray and not a finished dosage form. If a page tells you it is buying you a ready-to-use nasal product from this vendor, it is describing something the catalogue does not contain.

The reason the comparison matters at all is that a bottle price without a mass cannot be turned into a cost per milligram, and cost per milligram is the only figure that survives a move between storefronts. The next section is the conversion that fixes that, when the label gives you enough to work with.

Percentage strengths on a solution are weight in volume unless stated otherwise, which makes the conversion mechanical. One percent weight in volume is one gram in one hundred millilitres, which is 10 mg/mL. Everything else scales from there.

These are worked conversions, not quotes from any seller. The last column exists to do one job: convert whatever a bottle contains into the material cost of the same mass at this vendor's rate, so a bottle price can be read as a premium over the raw material rather than as a number floating on its own. A 5 mL bottle at 0.1% holds five milligrams, which is half of one vial and $15.00 of material at the code price. Whatever the bottle costs above that is buying formulation, filling, the delivery device and the seller's margin, and some of that is worth paying for.

Two conversion traps are worth naming. A percentage with no bottle volume gives you a concentration and no mass, so it cannot be priced at all. And a bottle quoted only in total milligrams gives you a mass and no concentration, which tells you what you bought but nothing about what an actuation delivers. You need both numbers, and a label that gives one and not the other is not being coy about the hard number by accident.

Actuation volume is the third variable and the one most often missing. A metered pump delivers a fixed volume per press, commonly somewhere between 0.05 and 0.1 mL, and the mass delivered is that volume times the concentration. If the label does not state the metered volume, no arithmetic on this page can tell you what one press contains, and nobody else's arithmetic can either.

The dry vial converts into the same units, with the difference that you choose the concentration rather than inheriting it. These are laboratory handling figures for research material and not instructions for administering anything.

At 2 mL the numbers are as tidy as this compound gets: 5 mg/mL, one U-100 unit is 0.01 mL and therefore 50 mcg, ten units draws 500 mcg, and the whole vial is 200 units of volume. Note that 5 mg/mL is the same concentration a 0.5% solution would carry, so the vial can be brought onto exactly the same scale as a bottle label without any special pleading.

The cost per unit column is the one to distrust across formats. It falls from 30 cents to 6 cents for the same $30.00 purchase, because a unit is a volume and not a mass. Half a milligram costs $1.50 in every row. That is why a spray priced per bottle and a vial priced per milligram can only be compared after both have been reduced to mass. Our syringe measurement guide covers reading the barrel, and the Semax calculator will run any volume you enter.

One correction the tables above do not carry. Batch 30-05260628 was weighed at 11.23 mg rather than 10 mg, so 2 mL of diluent gives 5.615 mg/mL and a unit holds 56.15 mcg. If a net content is published for your batch, divide that figure by your volume rather than dividing the label figure.

This is where the format question stops being about convenience. FDA's stated concern with this compound is immunogenicity, and it is a testing concern: compounded drugs containing semax (heptapeptide) may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation and peptide-related impurities, and the agency writes that it lacks sufficient information to know whether the drug would cause harm if administered to humans. Aggregation and impurity are measurable. A certificate is where you find out whether anybody measured them.

Batch 30-05260628 carries two results that most research peptide certificates do not. A bacterial endotoxin test by kinetic chromogenic LAL to USP Chapter 85, run on 29 May 2026 against an E. coli O111:B4 standard with a detection range of 0.01 to 1.0 EU/mL, reporting under 0.20 EU/mL against an acceptance limit of 0.5 EU/mL. And a rapid sterility screen, two days of incubation at 30 to 35 degrees, no bacterial growth and no fungi or yeast detected.

Here is the part almost nobody notices, and it is arithmetic rather than chemistry. Endotoxin is reported as a concentration, EU per millilitre, and the report states the volume it was measured in: 2.0 mL. Concentration scales inversely with volume, so the same total endotoxin in a smaller volume reads higher.

Under 0.20 EU/mL across 2.0 mL is under 0.40 endotoxin units in the vial in total, and that total is what a volume choice redistributes. Every volume of 1 mL and above stays inside the limit the certificate was written against. Below 1 mL it would not, which is a genuine reason to think about volume before you think about anything else.

Two limits on all of this. The sterility result is a rapid screen and the report says so on its own face, noting that full USP Chapter 71 sterility testing may be required for regulatory compliance. And a clean screen on one batch is evidence about one batch, not a safety finding about a substance FDA says it has no adequate human data on. A prefilled bottle that publishes neither test has not passed a lower bar; it has not been to the exam.

The two presentations differ most in when their shelf life begins, and that difference is worth more than any price gap between them.

A lyophilised vial is dry and sealed, and the clock on the solution has not started, because there is no solution. You decide when it does. A prefilled bottle has been in solution since it was filled, on a date you were not told, held at temperatures you cannot audit, through a shipping leg you did not observe. That is not an accusation about any particular seller. It is a statement about what information the format makes available to a buyer, and the answer for a bottle without a batch number is close to none.

The vendor lists the vial as lyophilised powder, and the certificate confirms the condition tested was lyophilised. General handling for material of this kind is covered in our peptide storage guide, which is the right place for the temperature and freeze-thaw side rather than a page about buying. What belongs here is the buying consequence: you can verify a dry vial against a batch certificate and a report number, and you cannot verify a bottle whose label carries neither.

Which certificate you get is a batch question rather than a product question, and that matters more than the format debate. Ascension publishes two Semax certificates. The February one, from MZ Biolabs on lot 30-01260229, reports purity of 99.75% and a quantity of 10.12 mg with identity by mass spectrometry, and carries no endotoxin test and no sterility screen anywhere in it. The June one, batch 30-05260628, carries both. Selank sits in exactly the same position with the same two dates, at $2.38 a milligram, 26 percent cheaper. So check the batch code on the vial you were sent rather than the compound name. Our Selank nasal spray page works the same format question from the cheaper side, and the Selank sourcing page covers which certificate arrives with which batch.