Patients with chronic migraines who took Botox had 7.8 fewer days per month with any headaches, including migraines, compared with 6.4 fewer headache days on placebo, according to a company-funded study released last year.
In separate research, patients getting Botox injections had 9 fewer days of headaches per month, compared with 6.7 fewer with a placebo.
That's not the reduction per month at all, it's the cumulative reduction at 24 weeks (6 months).
So really this is quite a modest effect size - arguably statistically significant but not clinically significant. A couple of neurologists I've discussed this with were generally underwhelmed although they do believe it has some effect.
That said, the market is big and I expect them to now get insurance coverage - previously patients had to self-pay to try this treatment.