What Is Botox Made Of? Three Ingredients, and One Strange Unit
Reviewed for medical accuracy against our Medical Review Board · Last updated 5 September 2026
Part of Botox Guides and Basics
Three ingredients. That is the entire formulation, and the prescribing information lists them plainly: botulinum toxin type A, human albumin, and salt.
The question behind this search is usually one of three: is it poison, is it made from something I would object to, and what am I actually paying for per unit. The label answers all three, and the third answer is stranger than most people expect.
1. The three ingredients
From the product data on the label itself:
| Ingredient | What it is doing |
|---|---|
| Botulinum toxin type A | The active drug |
| Albumin (Human) | Stabiliser, stops the tiny amount of protein sticking to the glass |
| Sodium chloride | Salt |
There is no preservative, no fragrance, no filler in the cosmetic sense and nothing of animal origin in the vial. There is also no latex, no gluten and none of the other things people write to ask about, because there is nothing in there at all beyond those three.
Worth knowing: the salt you are injected with is not this salt. The vial arrives as a dried powder and the clinic reconstitutes it, normally with sterile saline. That step is the clinic's, not the manufacturer's, which is why dilution is a variable and why our pricing guide treats it as one.
2. The human albumin, which is the part people ask about
Albumin is a protein from human blood plasma. It is in the vial because the active quantity of toxin is so small that without a carrier protein it would adsorb onto the glass and the syringe and never reach you.
That is a genuine consideration for some people and it is rarely mentioned at consultation. If you avoid human blood-derived products for religious reasons, because of a personal position on donated plasma, or on any other grounds, then this matters and you are entitled to know before rather than after.
It is also the single clearest difference between the approved brands. Daxxify uses a peptide instead of human albumin, which makes it the only one of the six with no blood-derived component. If that is your reason for asking, that is the product to raise. Our comparison of the approved products covers what else separates them.
3. How it is actually made
The label describes the process in one sentence, and it is worth unpacking because "made from bacteria" sounds alarming and "purified by acid precipitation" does not.
Botox Cosmetic is produced by fermentation of the Hall strain of Clostridium botulinum type A. The bacteria are grown, they produce the toxin, and then the toxin is separated out: purified from the culture solution by dialysis and a series of acid precipitations, down to a complex of the neurotoxin and several accessory proteins. That complex is dissolved in sterile saline containing human albumin, filtered through a 0.2 micron filter, and vacuum-dried into the powder that reaches the clinic.
So there are no live bacteria in the vial, and nothing that can grow. What is in there is a purified protein, dried.
The phrase accessory proteins in that description is the one to remember. They are left over from the purification and they do nothing therapeutically. Xeomin is manufactured to remove them, which is the entire basis of its "naked toxin" positioning, covered in the Xeomin guide.
4. A unit is a mouse lethality measurement
This is the part almost nobody says out loud, and it is stated openly in the label.
One Unit of BOTOX Cosmetic corresponds to the calculated median intraperitoneal lethal dose, the LD50, in mice. The unit on your invoice is not a weight or a volume. It is a dose defined by how much of it would kill half of a population of mice.
That sounds macabre and it is simply how biological potency has been measured in this class for decades: the material varies batch to batch, so it is standardised by effect rather than by mass. Modern release testing for Botox Cosmetic uses a cell-based potency assay rather than live animals, which the label also states.
The consequence for you is practical, and it is the reason a per-unit price comparison between brands is meaningless. The label is explicit: because of the specific vehicle, dilution scheme and laboratory protocols used in that assay, units of BOTOX Cosmetic cannot be compared to nor converted into units of any other botulinum toxin. A Dysport unit was measured in a different laboratory against a different reference. Our unit conversion guide sets the labelled doses side by side.
5. So is it poison
Botulinum toxin is one of the most potent biological substances known, and that is not a marketing exaggeration. The relevant question is dose.
A glabellar cosmetic treatment is 20 Units. The label's approved doses for medical conditions run into the hundreds, and its own boxed warning concerns the effect spreading beyond the injection site. So this is a genuinely powerful drug used at a small fraction of its therapeutic dose, in a muscle, by prescription. It is not a cosmetic in the regulatory sense and should not be bought or handled as one, which is the whole argument of our page on unapproved products.
What it is not is poisonous in the sense of accumulating or of damaging tissue. Section 12.1 describes a reversible mechanism: the nerve connection is blocked and later rebuilt. The main guide covers that in detail.
6. What the other brands are made of
- Xeomin is purified further, to remove the accessory proteins. Marketed as the naked toxin.
- Daxxify replaces human albumin with a peptide. The only one of the six without a blood-derived component.
- Dysport, Jeuveau and Letybo are all botulinum toxin type A with their own formulations and their own established names, which is why the FDA gave each a distinct prefix.
Every one of them is the same toxin type acting on the same target. The differences are in what is around it in the vial.
7. What arrives at the clinic
A single-dose vial of vacuum-dried powder, in 50 or 100 Unit sizes, carrying US License number 1889 on the label and carton. It is stored refrigerated at 2 to 8 degrees Celsius, and once reconstituted the label says to keep it refrigerated and administer within 24 hours.
Single-dose is the phrase worth holding on to. A 100 Unit vial used for a 20 Unit glabellar treatment leaves 80 Units, and the label's position is that the remainder is discarded rather than saved for the next patient. That is a real part of what you are paying for, and it is the honest answer to why a treatment is not one fifth the price of a vial.
Two things you can reasonably ask to see: the vial, and the lot number recorded on your notes. Both are ordinary requests.
Frequently asked questions
What is Botox made of?
Does Botox contain human blood products?
Is Botox vegan?
Is Botox actually a poison?
What is a unit of Botox?
Are there live bacteria in Botox?
How is Botox stored?
Sources
Every figure on this page was read from the documents below rather than from a clinic or a manufacturer's marketing. They open in a new tab so you can check any claim here against its source.
- BOTOX Cosmetic (onabotulinumtoxinA) for injection, full prescribing information, US National Library of Medicine, DailyMed
- Xeomin (incobotulinumtoxinA) for injection, full prescribing information, US National Library of Medicine, DailyMed
- FDA-approved botulinum toxin products, US Food and Drug Administration
Know the count before the quote. The unit count is half the bill, and a low per-unit rate recovered by a high unit count is the commonest way a deal is not one. How to tell.
Deciding which area, not how many units? Botox by facial area covers what each zone actually achieves, which four are FDA approved, and the things Botox cannot fix at all.
