Hormone Restoration in Dogs

Gonadectomy has some positive health outcomes as well as reducing pet overpopulation. Gonadectomized dogs are not as likely to have diseases associated with sex organs, such as mammary, ovarian and testicular cancers, pyometra uterine infection, and prostate enlargement. And not all dogs will succumb to health problems after being spayed or neutered. There are a complex set of variables that appear to influence the importance of sex hormones, including the age of the dog when spayed or neutered, the breed, the sex of the dog, and its size. Health issues seem to be common in dogs that receive a spay or neuter at a young age and large breed dogs who lose hormones before they finish growing.

To avoid potential health and behavior issues related to spay and neuter, pet owners can choose a hormone-sparing sterilization method, such as vasectomy for males and hysterectomy (also called ovary-sparing spay) for females. For more information, see details on our Hormone-Sparing Sterilization page.

Hormone restoration for dogs that may be suffering from a lack of natural hormones

Most dogs have already received a traditional spay or neuter surgery, removing the ovaries or testes. In fact, pet shelters or rescue organizations usually require that dogs and cats are spayed or neutered before adoption. Some of these pets will develop health or behavior issues due to the loss of natural hormones.

In humans, a loss of hormones due to injury or disease would be treated by hormone therapy to maintain health. This includes treatment with estrogen, testosterone, or other hormones. Couldn’t we supplement the lost hormones in spayed or neutered dogs to treat or prevent health conditions?

While restoring normal hormone levels in spayed and neutered dogs seems like a logical treatment option, it is not a standard veterinary treatment. Very little research has been conducted on this topic. Most published research in dogs is related to urinary incontinence. This is a common problem in female dogs after being spayed, especially large breeds and those spayed at an early age.

Incontinence in females has been treated successfully with various estrogens and gonadotropin-releasing hormone (GnRH) agonists (e.g., deslorelin), and GnRH immunization. These treatments restore urinary continence by reducing luteinizing hormone (LH) concentrations.

One publication in eight male dogs reported treating urinary incontinence with testosterone cypionate (median dose of 1.5 mg/kg intramuscularly every 4 weeks). The treatment worked well for two dogs but was not effective in half of the dogs. However the treatment was considered safe. Other treatments for male dog incontinence include phenylpropanolamine (PPA), estrogens, surgery and anticholinergic drugs. Studies are usually small and medical therapy has not been very effective.

Case study on hormone restoration in a neutered dog

Research on restoring natural hormone levels in dogs after spay or neuter is generally lacking. But a recent case report provides a bit of guidance. Published in Topics in Companion Animal Medicine, this study reviewed the use of hormone restoration therapy in a neutered male dog that had significant health issues shortly after gonadectomy received at seven months of age. Weight gain, loss of mobility due to pain in the right hip, and debilitating fear of strangers significantly reduced the dog’s quality of life.

After three years of standard medical treatments with no significant improvement, hormone restoration was attempted when the dog was about 4 years old. Low testosterone was increased with injectable testosterone cypionate and a weekly subcutaneous dose (0.5 mg/kg) was found to provide a steadier level than a monthly dose. But this dog also had extremely high luteinizing hormone (LH) levels that did not come down to the normal range with testosterone alone. The use of a gonadatropin-releasing hormone agonist implant (deslorelin) effectively reduced LH levels.

Within months, this treatment resulted in improved mobility, stabilized weight, and  reduction in fear and anxiety. The dog could run, jump, and visit public parks  – things he could not do previously without pain or extreme anxiety. He also accepted the weekly injections happily with positive reinforcement training.