Will 20 units of Botox along the hairline cause eyebrow dropping?

Botox/Xeomin neurotoxins do not "lift" anything.  This is urban legend propagated by the vast number of  injectors who do not know the anatomy or how neurotoxins work.  Neurotoxins work by paralyzing  the muscles of expression.  Forehead muscles lift the brows, so if you paralyze them, the brow may drop to varying degrees. You can affect brow position by paralyzing antagonistic muscles (muscle that act against each other). Weaken one, the other dominates. If you weaken the muscles in the crows feet area, you may achieve some lift of the lateral brow as the foreheads muscles now dominate.  But if you also paralyze the forehead, the effect is neutralized.  If you only paralyze the frown lines,  the mid brows can sometimes drop slightly, giving the illusion that the lateral brows have been lifted. This is the theory of relativity, but not Einstein's theory of relativity :)

Botox works by relaxing the musles it is injected into, and therefore preventing creasing of the skin. It is important that injectors understand the mechanisms of the facial muscles.For example- the forehead muscles, called the frontalis, work to elevate and raise your brows upwards. By injecting 20units into the forehead, the opposite effect occurs and your brows will not raise. When clients request a brow lift, an injector should treat the “depressor” muscles of the upper/mid face. These muscles are activated when making a frowning face or squeezing your eyes together tightly. Injections would occur between the eyebrows and at the tail of the eyebrows. 

Normally, when Botox is used to help lift the brows, the injection is placed just below the brows.  This weakens the muscle that pulls the eyebrows down and thus causes them to raise a bit.  Injecting Botox anywhere above the brows, including along the hairline, should not cause the brows to raise.  

Dear Yolanda00,Thank you for your question. What your injector is describing does not anatomically make sense. The frontalis muscle along the hairline pulls your eyebrows up. Inactivating any part of it will decrease upward pull on the eyebrows.Good luck,Nirmal R. Nathan, M.D.
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgeons

When injecting Botox in the Forehead by your hairline it will not cause the eyebrows to raise. When patients come to see me for Botox and are wanting a chemical eyebrow lift I inject slightly under the outer brow. By doing this it paralyzes that muscle that pulls the eyebrow down and thus causes the eyebrow to raise.  I hope this helps and be sure to see a Doctor who is Board Certified to get the best care.