The standard dose for glabellar lines is 20 units of Botox, split across five injection sites. That’s the FDA-approved amount for most women, but real-world doses range from about 15 units on the low end to 40 units or more, depending on your anatomy, sex, and how deep your frown lines are.
The Standard 20-Unit Protocol
The FDA label for Botox Cosmetic specifies 4 units injected into each of five sites in the glabellar complex: two injections in each corrugator muscle (the muscles that pull your brows together) and one in the procerus muscle (the muscle that pulls your brows downward). That totals 20 units per treatment session.
In clinical practice, some providers use slightly less. One study of patients treated for both glabellar lines and crow’s feet found that practitioners used an average of about 15 units in the glabella, below the standard 20-unit recommendation, and still achieved noticeable results. Your provider may start conservatively and adjust upward at a follow-up visit, typically scheduled about two weeks after your first treatment. Touch-ups at that appointment are usually small, around 1 to 2 units added to whichever spots still show movement.
Why Men Typically Need More
Men have larger, thicker muscles in the forehead and brow area, which means they need more toxin to achieve the same effect. The recommended starting dose for men is 40 units in the glabellar complex, double the standard female dose. Some men require up to 80 units. Under-dosing is the most common reason men are disappointed with their results, so if you’re a man and your provider suggests only 20 units, it’s worth discussing whether that’s enough for your anatomy.
What Affects Your Unit Count
Beyond sex, several factors influence how many units you’ll need. Stronger muscles require more product. If you can create very deep furrows when you frown, your corrugator muscles are likely on the thicker side. Age plays a role too, though not always in the direction you’d expect. Older patients sometimes have weaker muscles that respond to fewer units, but they may also have deeper static lines (wrinkles visible even at rest) that Botox alone can’t fully smooth.
Your provider will likely start with a conservative dose at your first visit and use the two-week follow-up to gauge your response. From that point on, they’ll have a reliable baseline for future appointments. The number that works for you tends to stay fairly consistent over time, though some long-term patients find they need slightly less as their muscles gradually weaken from repeated treatments.
How Dosage Affects Duration
Higher doses don’t just produce a stronger effect. They also last longer. At the standard 20-unit dose, results typically last around 17 to 20 weeks before frown lines return to their baseline severity. In a study of 226 women, doubling the dose to 40 units extended that median duration to about 24 weeks. Doses of 40 to 80 units all showed similar longevity, suggesting there’s a ceiling where adding more units stops buying you extra time.
That trade-off matters if you’re deciding between the minimum effective dose and something higher. Fewer units mean lower cost per visit but more frequent appointments. More units cost more upfront but can stretch your results from roughly four months closer to six.
The Risk of Eyelid Drooping
The main concern specific to glabellar injections is eyelid ptosis, a temporary drooping of one or both upper eyelids. This happens when the toxin migrates from the injection site into the muscle responsible for lifting your eyelid. It occurs in about 3% of glabellar treatments.
Technique matters more than dose here. Injections placed too deep or too far lateral along the corrugator muscle are more likely to cause migration. Some practitioners reduce risk by using only three injection points instead of five, skipping the outermost corrugator sites. After your injections, avoid rubbing or massaging the treated area, which can push the toxin beyond where it was placed. If ptosis does occur, it resolves on its own as the Botox wears off, though that can take several weeks.
What It Costs
Most providers in the U.S. charge between $10 and $25 per unit. At the standard 20-unit dose, that puts a glabellar treatment in the $200 to $500 range. Men needing 40 units can expect to pay roughly double. Some clinics offer flat-rate pricing per area rather than per unit, which can work in your favor if you need a higher dose. It’s worth asking how your provider structures pricing before your appointment, since the per-unit cost varies significantly by region and practice type.
Upper Safety Limits
The FDA sets a maximum cumulative dose of 400 units across all treatment areas within any three-month period. For the glabella alone, staying at or below 40 units is the most studied range with well-documented safety data. Higher doses (up to 80 units in men) have been used in clinical practice, but these are less common and require an experienced injector comfortable working outside the standard label.