The standard dose for treating 11 lines (the vertical frown lines between your eyebrows) is 20 units of Botox, split across five injection sites. That’s the FDA-approved amount, and it’s the starting point most providers use. In practice, the number can range from 20 to 30 or more units depending on your muscle strength, gender, and how deep the lines are.
The Standard 20-Unit Protocol
The FDA-approved treatment calls for 4 units injected into each of five sites, totaling 20 units. Two of those injection points go into each corrugator muscle (the pair of muscles that pull your brows together when you frown), and one goes into the procerus muscle (the small muscle between your brows that pulls them downward). These three muscles work together to create frown lines, though the corrugator does the most work.
Some practitioners use a slightly different mapping. A 2022 anatomical study proposed four injection points rather than five, using just 6 units total with a more precise targeting of medial and lateral points along the brow. This illustrates how technique varies from provider to provider. The 20-unit standard remains the most widely used starting dose, but your injector may adjust based on their training and your anatomy.
Why Some People Need More
Twenty units works well for many women with average muscle mass, but it’s not a universal number. People with stronger, thicker corrugator muscles need more product to achieve the same relaxation. This is a straightforward relationship: bigger muscles require more neurotoxin to quiet them down.
Men are the clearest example. Male facial muscles are typically larger and stronger, so men often need 30 units or more for their 11 lines. When treating both the forehead and the glabellar area together, men may require 40 units or more total. Your provider will assess your muscle strength during the consultation, often by asking you to frown hard so they can see and feel the muscles contract. If your lines are deeply etched at rest (meaning they’re visible even when your face is relaxed), you may also need a higher dose or multiple sessions before seeing full correction.
What Results Look Like and How Long They Last
You won’t walk out of the appointment with smooth skin. The toxin begins working one to two days after injection, with the effect building over the first week. Most people see the full result by day 10 to 14. If you’re getting Botox before an event, plan your appointment at least two weeks ahead.
Results typically last three to four months, though some people get five or six months of noticeable improvement. Clinical studies most commonly report a four-month duration. The minimum recommended interval between treatments is 12 weeks, but based on how long the effect lasts for you individually, some people do well with just two treatments per year rather than the three or four that a strict 12-week schedule would require. Over time, with consistent treatments, the muscles can weaken enough that you may need fewer units or less frequent visits.
Cost for Treating 11 Lines
Most providers in the U.S. charge $10 to $25 per unit, which puts a standard 20-unit glabellar treatment in the $200 to $500 range. If you need 30 units, expect to pay proportionally more. Pricing varies significantly by geographic region and by the experience level of the injector. Some clinics offer per-area pricing instead of per-unit, so ask how your provider charges before your appointment.
Botox vs. Dysport Units
If your provider uses Dysport instead of Botox, the unit numbers will look very different. The approved Dysport dose for 11 lines is 50 units, compared to Botox’s 20. That doesn’t mean you’re getting more product. The units simply aren’t equivalent between brands. Research has tested various conversion ratios, from 2.5:1 to 4:1 (Dysport to Botox). At a 2.5:1 ratio, Botox appeared more effective. At 4:1, efficacy was similar but side effects increased with Dysport. The optimal ratio likely falls somewhere in between. The cost per treatment tends to be comparable between the two brands once the unit difference is accounted for.
The Main Risk to Know About
The most talked-about side effect specific to this area is eyelid drooping, which occurs in about 3% of glabellar treatments. It happens when the toxin migrates beyond the intended muscles and reaches the muscle responsible for lifting your upper eyelid. The drooping is temporary, typically resolving within a few weeks as the toxin wears off, but it’s one reason precise injection technique matters so much in this area.
To reduce this risk, avoid rubbing or pressing on the treated area for at least 24 hours after your appointment. Staying upright for four hours post-treatment is another common recommendation. Choosing an experienced injector who understands the anatomy of the brow complex is the single most important factor in avoiding complications.