How long after a male cat is neutered?

Question

...is all of the testosterone out of his system?

Is it immediate or does it take several days?

Answer 1

It takes about a month for the testosterone to completely leave his system.

Answer 2

It kind of depends on his age - the older he was when neutered the longer it takes.  The worst of it though is gone in about 10-14 days.  It may take up to a month or so though for it all to be gone, if he was over 18 months or so when neutered. When his urine no longer stinks, then the testosterone is pretty much gone.  

Answer 3

As with humans, it takes a few days.

Answer 4

At least a month for the testosterone to be out but the spraying may continue if it is a behavioral problem.

Good luck.

Answer 5

I work at a vet clinic.  It can take up to a month to get the testosterone out of the system.  If you're dealing with a spraying male - it can take a good month before you know if the problem is now behavioral or if it was caused by the testosterone.

Best wishes...