Chemical Castration for Dogs

Chemical castration is an option for dogs 3 to 10 months of age using a chemical called Neutersol. Neutersol is FDA approved and 99.6% effective. Neutersol contains zinc gluconate, which halts growth of developing sperm, which atrophies the testes and prostate. By doing this, it renders the dog infertile. Neutersol was in use by many animal shelters, because the procedure was much cheaper and faster than surgical neutering of their animals.

However, Neutersol's production was halted in 2005, with plans to be reintroduced in 2009, but those plans have been put on hold. 

How It's Administered

Neutersol is administered with an injection into each testicle, and the amount given is determined by measuring the testicles at their widest points. 

Pros of Chemical Neutering

  • No anesthesia. This is easier on younger dogs, such as puppies, than placing them under for surgery. If the vet has trouble with the injections, a mild sedative often needs to be used to make your dog temporarily drowsy while the injections are given. 
  • Minutes versus hours. The injections take minutes at most, while regular surgical neutering can take hours, as well as much blood work and testing prior to putting a dog under.
  • The dog remains "intact." It may be important for some owners that their dog retains his testes. 

Cons of Chemical Neutering

  • Testosterone levels. Unlike with the surgical procedure, chemical neutering doesn't do much to drop the level of testosterone in the dog's body. Therefore, chemical castration does not eliminate a dog's chances of developing testicular cancer
  • Behavioral effects. Many owners get their dogs fixed for behavioral purposes, such as roaming and marking. Chemical neutering does not seem to get rid of these behaviors. 
  • Irritation. At the site of injection, the testicles can become irritated and inflamed. Although these types of effects happen in few cases, many owners don't want to take the risk.
  • No 100% guarantee of effectiveness. Although 99.6% only leaves a .04% chance of the procedure not working, that is .04% of pregnancies the owner did not want. Surgical neutering gives a 100% guarantee against unwanted pregnancies.

Side Effects of the Injections

  • Scrotal pain one to three days after injection
  • Mild, temporary swelling
  • Scrotal irritation or dermatitis
  • Low white blood cell count
  • Anorexia
  • Lethargy
  • Diarrhea

Side effects are generally temporary. Most occur in only about 1 to 5% of puppies. 

Alternatives to Chemical Castration

A standard surgical procedure to remove the testes is the most obvious alternative a vet will suggest. It cuts out the chance of testicular cancer, diminishes the chance of prostate cancer and gets rid of unwanted behavior such as marking. 

If you still aren't comfortable putting your pet under, ask your vet about Tardac. Tardac is another chemical used for chemical neutering, but its effects last only about 3 months, and it works by suppressing the testosterone hormone.