The standard dose for treating 11 lines (the two vertical creases between your eyebrows) is 20 units of Botox, split across five injection sites. That’s the FDA-approved protocol, but the number you actually need can range from 10 to 40 units for women and 20 to 80 units for men, depending on your muscle strength, the depth of your lines, and your goals.
The Standard 20-Unit Protocol
The FDA-approved treatment calls for 4 units injected into each of five spots: two injections in the muscle on each side of your brow (the corrugator, which pulls your eyebrows together when you frown) and one injection in the flat muscle between them at the top of your nose (the procerus, which pulls the skin downward). That totals 20 units.
Interestingly, if your lines follow a true “11” pattern, meaning two clean vertical lines with no horizontal creasing, your corrugator muscles are doing most of the work while your procerus stays relatively quiet. Some injectors will adjust the placement accordingly, focusing units more medially along the corrugator and potentially reducing or skipping the procerus injection altogether.
Why Some People Need More
Twenty units is a starting point, not a universal answer. In clinical trials testing different doses in women with moderate to severe frown lines, 20 units worked, but 40 units produced noticeably better results. Above 40 units, improvements in women plateaued, suggesting a ceiling effect around that dose.
Men typically need significantly more. A dose-ranging trial in 80 men found that response rates climbed steadily with higher doses: 65% of men responded at 20 units, 90% at 40 units, 95% at 60 units, and 100% at 80 units. The duration also improved, lasting an average of 17.6 weeks at 20 units versus 24.2 weeks at 80 units. No clear ceiling was found in men, largely because male facial muscles tend to be thicker and stronger.
Your provider will assess your muscle strength during a consultation, often by asking you to frown hard while they feel the area. If your muscles are particularly strong or your lines are deeply etched at rest, expect a recommendation above 20 units.
What the Treatment Feels Like
The injections themselves take about five minutes. Each of the five sites gets a tiny volume (0.1 mL), so you’ll feel a quick pinch at each spot. The deeper injections near the inner brow go close to the bone, while the outer ones sit more superficially in the muscle. Most people describe it as mild and tolerable without numbing cream, though your provider can apply one if you prefer.
You’ll start noticing changes within two to four days, with about 84% of the smoothing effect visible in that early window. The full result peaks around day 14. From there, the effect gradually fades over three to five months as nerve signals to the muscle slowly recover.
How Long Results Last
Most people schedule repeat treatments every three to four months. At the five-month mark, clinical data shows over 75% of patients still have a visible improvement compared to their baseline, so some people can stretch their appointments further.
There’s a compounding benefit to consistent treatment. Repeated injections cause the targeted muscles to gradually thin out from disuse, which means your results can last longer over time. A study tracking 945 patients through at least three consecutive treatments found no loss of effectiveness with repeated sessions. After five treatment cycles, both patients and their providers rated satisfaction higher than after the first round.
Risks to Know About
The most talked-about side effect is eyelid drooping (ptosis), which happens in roughly 3% of glabellar treatments. It occurs when the toxin migrates beyond the injection site and reaches the muscle responsible for lifting your eyelid. The risk is higher when injections are placed too low or too close to the eye, or if you rub the area aggressively afterward. Ptosis is temporary, typically resolving within a few weeks as the effect wears off.
Bruising at the injection sites is common but minor. Headache can occur in the first day or two. Serious complications are rare when the treatment is performed by an experienced injector who understands the anatomy.
What It Costs
Botox is priced per unit, and the going rate falls between $10 and $30 depending on where you live and who’s injecting. Urban practices typically charge $15 to $25 per unit, while rural areas may run $10 to $15. For a standard 20-unit glabellar treatment, that puts your total somewhere between $200 and $600. If you need 30 or 40 units, adjust accordingly.
Price per unit matters more than total cost when comparing providers. A quote of “$300 for frown lines” doesn’t tell you much unless you know how many units are included. Fewer units at a lower price can mean underwhelming results and a shorter duration, which ultimately costs more per month of smooth skin. Ask for the unit count and per-unit price so you can compare apples to apples.