What the research shows
The outer brow drops first because it has less support. Beyond a ridge on the side of the skull, the soft tissue slides down over the temple, and the frowning muscles and the muscle around the eye pull the outer brow down against the forehead muscle that holds it up (Knize 1996).
The inner brow does not fall the same way. In women, the brow sat higher at the inner and middle points in their 50s than in their 20s. The authors concluded that lifting the inner and middle brow looks neither young nor natural, and that lifting the outer brow does (Matros 2009). A panel of surgeons and cosmetologists placed the ideal inner brow at or below the bone, with the arch slanting up toward the outer end, and found that standard brow lifts often put the inner brow too high (Freund 1996). Over the past decades the ideal peak of the brow has moved outward, to sit above the outer corner of the eye (Griffin 2013).
Upper eyelid surgery can bring the brow down. In one series the brow dropped in about a third of cases, more often in men, and the authors advise discussing it before surgery and fixing the brow at the same time when needed (Hassanpour 2016).
Each technique lifts a different amount. Releasing the brow through the eyelid incision prevented the drop; adding a stitch raised the outer brow; removing the frowning muscles raised the inner and middle brow; an endoscopic lift raised it most (Georgescu 2010). A large endoscopic series without muscle removal raised the brow by a few millimeters at every point, with few complications or revisions (Liu 2026).
Botulinum toxin also moves the brow. Injections between the brows at standard doses lifted the outer brow first and then the middle and inner brow, with the peak at about 12 weeks; the lowest dose caused a mild early droop (Carruthers 2007). Injections in the forehead cause a dropped brow in about 1 to 5 in 100 treatments in published studies, fewer with correct sites and doses (Redaelli 2003).
Where surgeons disagree
- Whether to lift the inner brow. One view is to raise only the outer brow (Matros 2009, Freund 1996). A recent endoscopic series raised the inner, middle and outer brow by similar amounts and reports good outcomes (Liu 2026).
- Whether eyelid surgery lowers the brow. One series found a drop in about a third of patients (Hassanpour 2016); an earlier one found no meaningful change in most patients with already low brows, and all were pleased (Fagien 1992).
- Whether a brow stitch from the eyelid lasts. It added outer lift in one comparison (Georgescu 2010); over five years the stitched brow came down while the endoscopic brow stayed up (Iblher 2012).
What is new
- Patients worry that an endoscopic lift makes the forehead taller. Measured with the eyes closed, the forehead did not lengthen; it only looked longer because the forehead muscle relaxed after surgery (Xu 2026).
- Uneven brows can be evened out by releasing the ligaments on each side by a different amount (Bair 2026).
- The direct brow lift, with an incision just above the brow, held its position at one year and scars looked better with time (Marangi 2026); a review found the scar hard to see in most patients (Khan 2026).
- Loss of vision at the outer side of the visual field helps decide when a sagging brow needs repair along with the eyelid, and combined repair needed fewer revisions (Stein 2026).
What is still unknown
- How to measure the brow the same way across studies. Forehead muscle tension changes readings taken with the eyes open (Xu 2026).
- The ideal brow for men. The aging and beauty studies measured women (Matros 2009, Freund 1996), and men's brows dropped more often after eyelid surgery (Hassanpour 2016).
Key papers
- Knize 1996: explained why the outer brow drops first.
- Freund 1996: defined the ideal female brow and showed standard lifts often missed it.
- Carruthers 2007: measured how botulinum toxin between the brows lifts them.
- Matros 2009: showed the inner brow rises with age in women.
- Georgescu 2010: compared how much each brow technique lifts.
- Iblher 2012: five-year comparison of endoscopic lift and brow stitch.
- Hassanpour 2016: measured the brow drop after upper eyelid surgery.
- Xu 2026: showed the forehead does not lengthen after an endoscopic lift.