What is a Botox unit, and why do clinics price per unit or per area?

Botox is priced in a way that surprises a lot of first-time buyers: by the unit. A unit is not a syringe or a vial. It is a measure of how much of the drug you receive, and a single treatment uses many units. So a per-unit price on its own does not tell you what you will pay. You also need the dose.

What a unit is

Botox Cosmetic is onabotulinumtoxinA, a purified form of the toxin that relaxes the muscles behind expression lines. Its strength is measured in units of biological activity, not by weight. A clinic dilutes a vial with saline and injects small amounts at several points. The number of units, not the volume of liquid, is the dose.

The FDA-approved label gives a total dose for each approved area. For example, frown lines between the brows (glabellar lines) are labeled at 20 units spread over five injection points, and crow’s feet at 24 units. Forehead lines are labeled at 20 units, given together with 20 units for the frown lines, and the label puts all three areas together at 64 units. Providers adjust for the size and strength of a person’s muscles, so your dose may differ from the label.

Per unit or per area

Clinics publish Botox prices in one of three ways:

• Per unit. You pay for the units injected. Simple to compare between clinics, harder to predict before your appointment.
• Per area. One price for the forehead, the frown lines or the crow’s feet, whatever number of units that takes. Easier to budget, but you cannot tell how many units the price assumes.
• Packages. A fixed number of units, such as 20 or 40, for one price.

To compare a per-area price with a per-unit price, ask the clinic how many units its per-area price includes, then divide. If a clinic will not say, compare it with the labeled dose for that area as a rough guide.

What clinics publish

These are the median per-unit prices that med spas publish on their own websites in each city we cover. Each figure is computed from the clinic prices on the linked page.

A median per-unit price times a typical dose gives a rough idea of a treatment. Each city page also lists the whole-treatment packages clinics publish, such as 20 and 40 units.

Why the cheapest unit is not always the cheapest treatment

• A low per-unit price may apply only to new clients, members or a minimum number of units.
• A follow-up touch-up may be free at one clinic and charged per unit at another.
• A clinic may use a different neurotoxin, whose units are not the same size. See our guide to Botox, Dysport and Xeomin.

The effect of Botox wears off gradually. Its label says the effect on frown lines lasts approximately three to four months, so the cost is a repeating one.