According to the VCA Animal Hospitals, dogs that have excitable natures are not calmer after being neutered. The only behaviors affected are those specifically linked to the presence of male hormones, which are no longer produced after the procedure.
VCA identifies hormone-driven behaviors that are typically reduced after neutering. Sexual behaviors, such as seeking out female dogs, roaming, mounting and masturbating, lessen or disappear. Male dogs are less driven to mark their territories and aggressive behaviors affected by hormones also decrease.
In addition to diminishing negative behaviors, VCA states that neutering prevents testicular cancer and lowers the odds of prostate cancer. Both are significant threats to older dogs that have not been neutered. Neutering also helps cut down on the number of unwanted dogs that are euthanized annually.