Index
- 1. Introduction
- 2. The Role of Hormones in Canine Health: More Than Just Reproduction
- 3. What Happens When Dogs Are Neutered and Spayed Conventionally?
- 4. The Known Risks of Conventional Spay and Neuter: What the Science Says
- 5. The Biology of Hormone Production in Brief
- 6. Hormone-Sparing Sterilization
- 7. How to Help Dogs That Have Been Spayed or Neutered By Conventional Methods
- 8. Real Stories
- 9. Watch or Listen to Interviews with Experts
- 10. Frequently Asked Questions (FAQ)
The Most Current Update on Healthier Alternatives for Your Dog’s Healthy Life and Longevity
Why Rethink Traditional Spay & Neuter?
For decades, early spaying and neutering have been considered essential for responsible dog ownership.
However, growing research shows that removing your dog’s reproductive organs and the hormones they produce can have significant long-term health and life-span consequences.
These include joint injuries, arthritis, chronic inflammation, organ dysfunction, certain cancers, and behavioral issues such as anxiety and aggression.
As of 2024, the World Small Animal Veterinary Association (WSAVA) no longer recommends routine spay/neuter for all dogs. Instead, they advise considering hormone-sparing alternatives that protect your dog’s health and well-being.[3]
The Role of Hormones in Canine Health: More Than Just Reproduction
Just like humans, every dog needs to have sufficient hormones to fully develop, have functioning organs, and reduce the risk of disease. Sex hormones play a vital role in reproduction; however, their role reaches far beyond reproduction.
The Role of Hormones in Your Dog’s Health
Hormones such as testosterone, estrogen, and progesterone play a vital role in your dog’s body, which reaches far beyond just reproduction.
They regulate metabolism, immune function, mood, cognition, memory, bone and muscle health, and more.
What Happens When Dogs Are Neutered and Spayed Conventionally?
When sex hormones are absent as a result of traditional spaying or neutering, your dog’s body compensates by increasing levels of luteinizing hormone (LH).
Research studies confirmed that chronically high LH often leads to inflammation, injuries, organ disease, tissue degeneration, higher risk of cancer and behavioral problems.
The Known Risks of Conventional Spay and Neuter: What the Science Says
Joint Disorders and Musculoskeletal Health
Dr. Benjamin Hart and his colleagues at the University of California, Davis, highlight in their research, the significant risks of joint disorders, particularly in large breeds.[5]
Cancer Risks
Studies have found that early neutering increases the risk of certain cancers, such as lymphoma, osteosarcoma, and hemangiosarcoma. Dr. Karen Becker explains that “Removing hormone-producing organs at a young age disrupts the endocrine system, leading to serious consequences like an increased risk of aggressive cancers”.
Behavioral Issues Linked to Hormonal Changes
Elevated levels of luteinizing hormone (LH) post-neutering can trigger inflammation in the brain, leading to anxiety, fear, and even aggression. Dr. Jack Oliver from the University of Tennessee, notes that these hormonal imbalances can make dogs more reactive to stress and prone to fear-based behaviors.[4]
The Biology of Hormone Production in Brief
The testicles and ovaries produce sex hormones, but the entire process starts in the hypothalamus, deep within the brain.
The hypothalamus acts as a bridge between the brain and the endocrine system, translating sensory signals (like a male smelling or seeing a female in heat) into hormonal messages. It releases GnRH (gonadotropin-releasing hormone), prompting the pituitary gland to secrete luteinizing hormone (LH).
LH then stimulates the gonads to produce testosterone and estrogen. When hormone levels drop, the pituitary senses this and releases more LH, creating a feedback loop much like a toilet tank refilling when the water is low and stopping when it’s full.
Hormone-Sparing Sterilization
A viable option of preserving your dog's hormone and preventing unwanted pregnancies.
Hormone-sparing sterilization methods allow your dog to remain non-reproductive while preserving the natural hormones essential for lifelong health.
|
Procedure |
Description |
Benefits |
|
Ovary-Sparing Spay (OSS) |
Removes uterus/cervix, leaves ovaries intact |
Prevents pregnancy & pyometra, preserves hormones, avoids menopause |
|
Vasectomy |
Severs vas deferens, leaves testicles intact |
Prevents reproduction, maintains hormones, avoids health consequences |
|
Traditional Spay/Neuter |
Removes ovaries/testes - NO LONGER RECOMMENDED |
Prevents pregnancy, but causes hormone loss and related health risks |
A Suggestion for Responsible Guardians:
Male dogs can remain intact if you can reliably prevent unwanted breeding through supervision and secure environments.
Female dogs are at 25% risk of pyometra, an inflammatory condition of the uterus that can be serious or life-threatening. There is a consensus that preserving ovaries and removing the uterus is the most reasonable compromise to preserve hormones and prevent pyometra.
For Shelters/Rescues:
Hormone-sparing sterilization (OSS or vasectomy) is the most reasonable option to prevent overpopulation while preserving the health benefits of natural hormones.
How to Help Dogs That Have Been Spayed or Neutered By Conventional Methods
Hormone Replacement Therapy (HRT) for Spayed/Neutered Dogs
If your dog has already been spayed or neutered, hormone replacement therapy (HRT) can help restore hormonal balance and address health issues caused by hormone loss.
Why Consider HRT?
Many dogs suffer from “spay and neuter syndrome”-chronic health and behavioral issues due to hormone loss. These can include joint pain, muscle wasting, cognitive decline, coat changes, and increased anxiety or aggression.
Protocols
For Males:
-
-
- Suprelorin (Deslorelin) implant to reduce LH
- Weekly testosterone injections (0.5 mg/kg subcutaneously)
-
For Females:
-
-
- Suprelorin implant if LH is high
- Oral estrogen (estriol or diethylstilbesterol) as prescribed by your veterinarian
- LH levels should be monitored before and after therapy
-
Benefits
A vast majority of dogs experience an overall improvement in general health, greater mobility, lower levels of inflammation, improved mood, coat quality, and lower rates of cancer.
Many dog guardians experience dramatic recoveries after starting HRT, regaining their vitality and quality of life, especially if they have a history of health issues.
What is Suprelorin (Deslorelin) and how does it work?
The Suprelorin implant is a small, biocompatible device placed just under the skin, usually between the shoulder blades, by a veterinarian in a procedure similar to microchipping that does not require anesthesia. It contains deslorelin, a GnRH agonist, which initially stimulates and then suppresses the production of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), leading to a significant drop in testosterone or estrogen and resulting in temporary infertility.
In intact dogs, Suprelorin is used for reversible contraception, while in spayed or neutered dogs, it helps reduce LH-driven inflammation and can improve health issues linked to hormone deficiency. The 4.7 mg implant lasts about six months and must be repeated for ongoing effect. Mild swelling or itching at the site may occur, but serious side effects are rare.
Suprelorin is approved for use in dogs in nearly 50 countries, including the EU, UK, Australia, New Zealand, Canada, Mexico, and China.
In the United States, it is only approved for ferrets, not dogs, though some veterinarians may consider off-label use with appropriate waivers.
Real Stories
What happened to my dog and his progress on Hormone Replacement Therapy
At the age of 18 months, my beautiful Border Collie, Pax, was a healthy and strong dog.
About six months after he was neutered, I started to notice that Pax would occasionally limp, getting progressively worse.
Tests, X-rays, and other exams were inconclusive, and despite rest, rehabilitation and physical therapy, he was not getting better.
For three years, we could no longer enjoy the beach, swimming, and mountain hiking together, and it was heartbreaking to see him hobbling around.
I was devastated.
His challenges prompted me to search for answers to his unexplained lameness, and eventually, I came across the research of Dr. Michelle Kutzler and Dr. Linda Brent and decided to start Pax on the hormone replacement therapy protocol mentioned above.[1][2]
His transformation has been incredibly positive, similar to dogs in the research studies.
Almost immediately, Pax became happier, had more energy, and slept less during the day. His coat has become thicker, his mane is longer and more pronounced. You can see what happened in the before and after video below.
He’s everything I would expect from a 5-year-old dog.
As for any negative effects, he has not displayed any. Except for more sniffing, being even more cuddly with us, friendly with other dogs and the rare attempt to "hump."
It took about two months for him to recover from his lameness and injuries. I am thrilled to report he’s been running, hiking, and swimming as before his procedure, and he is happy and injury-free.
He continues to get .2mg/kg of testosterone cypionate subcutaneously (injection under the skin) weekly and will get a new implant as required (every six or twelve months) depending on the potency of Suprelorin I decide on.
Pax started his treatment in April 2024 and continues to thrive.
Here is a video recorded a year after he started his treatment. He is happy, strong and continues to be injury-free
Here is also his most recent blood work, which demonstrates that hormone replacement therapy has an overall positive effect on general health.
Watch or listen to Interviews with Experts
If you’re undecided about this topic, would like additional reassurance, or just want to deepen your knowledge, I have conducted interviews with many of the experts mentioned here, and my colleagues below:
Featured Experts:
- Dr. Michelle Kutzler, DVM, PhD, DACT (Oregon State University)
- Dr. Linda Brent, PhD (Parsemus Foundation)
- Dr. Karen Becker, DVM
- Rodney Habib
- Dr. Peter Dobias, DVM, HMC
- Dr. Judy Morgan, DVM, CVA, CVCP, CVFT
- Dr. Ruth Roberts, DVM, CVA, CVA,CVH, CVFT
Dr. Karen Becker,DVM an integrative veterinarian and New York Times bestseller author and the person who sounded the alarm more than a decade ago. Rodney Habib - a top animal health, nutrition and welfare advocate and New York Times bestseller author.
Dr. Michelle Kutlzler, DVM, PhD, DACT board-certified reproduction specialist and professor at Oregon State University con, conducted some of the main research studies.
Dr. Linda Brent,PhD the Executive Director of the Parsemus Foundation.
Dr. Ruth Roberts, DVM, CVA, CVA,CVH, CVFT a veterinarian and advocate of HRT and hormone sparing sterilization and Dr. Linda Brent, PhD, the Executive Director of the Parsemus Foundation.
Frequently Asked Questions
Q: When is the best time to check LH (luteinizing hormone) levels?
A: It is advisable to check LH levels in dogs suspected of having an inflammatory condition, regardless of whether they are spayed/neutered or intact.
For older intact dogs, checking LH levels may be beneficial if they show health issues.
Q: Is Suprelorin always necessary, and is testosterone always required?
A: Using Suprelorin in addition to testosterone and estrogens is the preferred method of treatment of spayed and neutered dogs.
Q: Are there any natural ways to increase testosterone or estrogen in dogs?
A: I don't have any concerns about administering testosterone or estrogen to dogs as medication, as it helps replace missing hormones and can have significant positive effects. When a dog's ability to produce these hormones is impaired, providing appropriately formulated hormones at the correct dosage is the preferred option. While some glandular supplements may contain hormones, dosing them accurately would be challenging, so I would not recommend using these at this time.
Q: Can glandular powdered support supplements provide similar benefits to hormone replacement therapy?
A: While these supplements do not lower LH concentrations, they may offer some benefits in supporting glandular health in dogs with hormone imbalances linked to high LH levels, particularly concerning adrenal gland health. However, I generally prefer pharmaceutical-grade preparations when it comes to hormones. They can be dosed more accurately.
Q: Is it advisable to allow female dogs to undergo a few heat cycles before undergoing hormone-sparing surgery?
A: Theoretically, there is no necessity to wait for hormone-sparing sterilization surgeries in female dogs. However, I recommend that, even with hormone-sparing procedures, it is best to wait until the dog is at least 6 to 12 months old.
Q: Do female dogs continue to produce hormones through the uterus alone if ovaries are removed?
A: In female dogs that have had their ovaries removed but still have a uterus, hormone production is minimal. Generally, ovariectomy, or the removal of the ovaries, is not recommended because it can lead to a significant hormone deficiency.
Q: What should you do if a dog is intact and experiencing false pregnancies?
A: You can consider an ovary-sparing spay (hysterectomy). If this issue persists, you may choose to remove the ovaries later, preferably using laparoscopic techniques. However, it is advisable to be cautious about removing the ovaries. I recommend providing your female dog with small furry toys, which may help calm her down. Additionally, consult a homeopathic practitioner to address your dog's specific situation.
Q: Is an ovary-sparing spay (OSS) a more complex surgery compared to a traditional spay?
A: An ovary-sparing spay (OSS) is not a more complex surgery; it simply involves a different approach. In some ways, it can even be simpler because there is no need to remove and ligate the ovaries, which have a heavy blood supply. However, for the removal of the cervix, the surgeon must go deeper into the pelvis to ensure that all uterine tissue is completely excised. This procedure is technically a different technique; it is not more invasive or traumatic than a traditional spay. In fact, it may be less so since there is no sudden drop in hormone levels.
Q: What about pyometra, which is the inflammation and infection of the uterus?
A: Pyometra cannot occur if a complete hysterectomy is performed since there is no uterus remaining. However, if an ovariectomy is performed, there is still a risk of pyometra because it can develop with the presence of progesterone and a uterus.
For intact females, there is a risk of developing pyometra regardless of their age. Some studies indicate that the lifetime incidence of pyometra is about 25%, though this can vary depending on the breed.
Q: What is the relationship between mammary cancer and estrogen?
A: Estrogen may contribute to some mammary cancers; however, progestins are more commonly associated with mammary tumors in dogs. Regular breast exams are essential for early detection. Keep an eye out for anything unusual during routine belly rubs. Most mammary tumors in dogs are actually benign.
Q: For a dog that has been bred, is it better to have an ovary-sparing spay or to keep her intact?
A: There is a 25% chance that an intact dog will develop pyometra. Based on discussions with Dr. Kutzler, opting for an ovary-sparing spay is a reasonable choice to prevent pyometra in aging female dogs, especially if you want to avoid the risk of emergency surgery. Ultimately, the decision is personal. Some people believe it's better not to interfere with the body as a whole system, while others prefer a preventive ovary-sparing spay to reduce the risk of pyometra.
Q: Is there a possibility of a spike in LH after a dog has puppies at the age of six years?
A: A natural spike in LH occurs just before ovulation.
Q: Is there a difference in the protocol for dogs that are spayed or neutered later in their senior years?
A: There is no difference in the protocol for dogs that are spayed or neutered later in their senior years; the protocol remains the same.
Q: Have you noticed any changes in food sensitivities after hormone replacement is added?
A: Research indicates that luteinizing hormone (LH) can cause inflammation in the gastrointestinal tract. Therefore, it is possible that dogs with inflammatory bowel disease or leaky gut may experience a reduction in food sensitivities when hormone replacement is introduced. While research supports this possibility, it’s important to note that each dog is unique, and individual responses may vary.
Q: What would you recommend for a three-year-old Maltese with a portosystemic shunt and a small heart murmur?
A: While this situation may not be directly related to hormone replacement therapy, if this dog has high luteinizing hormone levels and shows symptoms of inflammation, I would still recommend hormone replacement therapy. It’s important to monitor the liver regularly, ideally at least once every three months. As for the heart murmur, its significance is uncertain without a full medical report, making it difficult to provide further comments.
Q: Is it safe to use hormone therapy alongside immunotherapy or chemotherapy when treating multiple cancers?
A: Currently, there is insufficient evidence regarding combined treatments for animals suffering from cancer and metastatic disease. Given that this condition is terminal, if I had a dog with cancer, I would seriously consider using Suprelorin to suppress the luteinizing hormone and potentially administer hormone replacement therapy. This approach may help reduce symptoms and improve the animal's overall health, but we still lack enough information to confirm its effectiveness in cancer treatment.
Q: Where in the U.S. is hormone-sparing sterilization surgery performed on cats? Is hormone replacement therapy possible?
A: Currently, there isn't enough information available to determine how cats respond to hormone-sparing sterilization or HRT. Unlike dogs, cats do not seem to be affected as significantly by spaying and neutering, based on what is known so far. Cats are also induced ovulators, which further complicates the issue. I recommend consulting a feline medicine expert who may be able to provide more insight on this topic. Our website focuses exclusively on canine medicine and health.
Help us Support the Movement:
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- Share this information with friends, family, and your local pet community
- Support ongoing research through organizations like the Parsemus Foundation
- Encourage your veterinarian to learn about hormone-sparing options
Further Reading
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References
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Brent, L., Lissner, E. A., & Kutzler, M. A. (2021). Restoration of reproductive hormone concentrations in a male neutered dog improves health: A case study. Top Companion Animal Medicine, 45,100565. https://doi.org/10.1016/j.tcam.2021.100565
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Kutzler, M. A. (2020). Possible relationship between long-term adverse health effects of gonad-removing surgical sterilization and luteinizing hormone in dogs. Animals (Basel), 10(4), 599. https://doi.org/10.3390/ani10040599
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Romagnoli, S., Krekeler, N., de Cramer, K., Kutzler, M., McCarthy, R., & Schaefer-Somi, S. (2024). WSAVA guidelines for the control of reproduction in dogs and cats. Journal of Small Animal Practice, 65(7), 424–559. https://doi.org/10.1111/jsap.13724
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Oliver, J. W. (2007). Steroid profiles in the diagnosis of canine adrenal disorders. In Proceedings of the 25th ACVIM Forum (pp. 471–473). Seattle, WA.
- Hart, L. A., Hart, B. L., & Thigpen, A. P. (2023). Decision-making on recommended age of spay/neuter for a specific dog: General principles and cultural complexities. Veterinary Clinics of North America: Small Animal Practice, 53(5), 1209–1221. https://doi.org/10.1016/j.cvsm.2023.05.005
- Parsemus Foundation - https://www.parsemus.org/
