How long for Botox to show results?

I am a 30yo male with an enlarged corrugator muscle in my eyebrow. I recently had 25 units injected into it and I wanted to know how long until the muscle shrinks? Also the effects seem to be inconsistent. It has been 16 days since the injection and sometimes I can move the eyebrow muscle completely and other times it is totally paralyzed. I have had botox once before with similar results. Any advice would be appreciated!


M, 33, Texas

Botox typically weakens the muscle function but is not intended to "shrink" the bulk of the muscle. I suppose patients who have regular, maintenance Botox to these muscles might notice atrophy from disuse over time but I do not know of any studies actually looking at that. If you feel like you still have movement in areas where you expected paralysis of the muscle, then you may need more Botox. Male patients typically need more than females so you may need to increase the number of units of your routine Botox treatment in the future.

Botox usually takes 4-5 days to start having an effect.  The muscle doesn't shrink, it just stops contracting.  It sounds like you make not have had an adequate amount of Botox to treat your affected area.  I would return to the person who performed the injection.  You may just need additional units to get you the result you are looking for.

2 days to a week. There are rare exceptions.

The effects of Botox™ are usually noticed 3-4 days after treatments, and may take up to 2 weeks before fully present. Results are temporary and last typically between 4-5 months.

Botox will eventually reduce the size of muscle groups if you continue to use it each time it wears off.  I would expect 9 to 12 months of continuous use to see an appreciable reduction in muscle size.