A typical forehead Botox treatment uses 10 to 30 units, with 20 units being the most common starting point. The exact number depends on your muscle size, the depth of your lines, and your sex, so two people can walk into the same clinic and leave with very different doses.
The Standard Dose Range
The FDA-approved dosing for forehead lines is 20 units, split evenly across five injection sites (4 units per site). This is the dose recommended by Allergan, the company that manufactures Botox Cosmetic. In practice, many providers work within a broader range of 10 to 30 units depending on what they see in front of them.
One important detail that often gets overlooked: the FDA labeling specifies that forehead lines should be treated alongside the frown lines between your eyebrows (the glabellar area), bringing the total recommended dose for both areas to 40 units. Treating the forehead alone, without also relaxing the muscles between the brows, increases the risk of brow drooping. The frown line muscles pull your brows down, and if those muscles are still at full strength while your forehead muscle is relaxed, gravity wins. This is why many providers treat both areas together even if your main concern is forehead lines.
Why Your Dose May Be Higher or Lower
Muscle size is the single biggest factor. Men carry roughly 60% more skeletal muscle mass than women on average, and while no study has directly measured facial muscle differences, the pattern holds in clinical practice. Research in Dermatologic Surgery found that 65% of men in a study group were classified as having large facial muscle mass, compared to 38% of women. Those with larger muscles and deeper lines consistently needed higher doses to see the same results. In one trial, researchers concluded that 20 units was inadequate for the glabellar area in men and recommended starting at roughly double the typical female dose.
For the forehead specifically, men often need doses at the higher end of the range (closer to 25 to 30 units), while women with mild lines and smaller muscles might do well with 10 to 15 units. Other factors that push the number up include very expressive facial habits, deep-set lines that are visible even at rest, and previous treatments where a lower dose wore off too quickly.
If you’re getting Botox for the first time, many providers start conservatively and add units at a follow-up visit two weeks later. Starting low lets your provider see how your muscles respond before committing to a higher dose.
What It Costs
Most U.S. providers charge $10 to $25 per unit. At 20 units for the forehead alone, that puts the typical cost between $200 and $500 per session. If you’re treating the frown lines at the same time (another 20 units), expect the total to land between $400 and $1,000 depending on your provider’s pricing and location. Prices vary significantly by city, with major metro areas and specialized cosmetic practices generally charging more per unit.
When Results Appear and How Long They Last
You may notice the first effects within 3 to 4 days as the muscle gradually weakens, but full results take 10 to 14 days to settle in. This is why providers who offer touch-ups typically schedule them at the two-week mark, once the initial dose has reached its peak effect. Judging your results before that point can lead to overcorrection.
Forehead Botox generally lasts 3 to 4 months. Most people maintain their results on a schedule of every 12 to 16 weeks. Going more frequently than every 3 months is not recommended, as it increases the theoretical risk of developing resistance to the treatment over time. Some people find that after several consistent sessions, their muscles weaken enough that they can gradually extend the interval between appointments.
Reducing the Risk of Drooping
The forehead muscle (frontalis) is the only muscle that lifts your eyebrows. Relaxing it too aggressively, placing injections too low on the forehead, or using too many units without also treating the frown area can cause the brows to drop, making your eyes look heavy or hooded. In rare cases, the product can migrate to the muscle that lifts the upper eyelid, causing a temporary eyelid droop.
Several things reduce these risks. Proper injection placement matters most, and that comes down to your provider’s skill and anatomy knowledge. Avoiding rubbing or massaging the treated area afterward also helps, since vigorous pressure can push the product beyond the targeted muscle. Even with perfect technique and appropriate dosing, spreading the product through physical manipulation can cause unintended effects. Any drooping that does occur is temporary, typically resolving within a few weeks as the Botox wears off in the affected area.