Zeuterin™ / Esterilsol™: The New Dog Neuter, Part 1

Problem: Animal Overpopulation

Nearly 4 million healthy and adoptable animals are destroyed annually in America, a fact that makes me sick to my soul. While surgical spay/neuter programs have successfully reduced needless deaths over the past decade, these procedures are often quite expensive. Rescue organizations who handle countless unaltered strays and surrenders bear significant financial burden and, while low-cost programs exist, they are spread too few and far between.

So, what else is there?

Solution: Zeuterin™ Non-Surgical Sterilant

Ark Sciences: Zeuterin

I recently learned of a small injection called Zeuterin™ in the US (known as Esterilsol™ globally) that neuters dogs for a fraction of the cost. It eliminates the need for an operating room, veterinarian (although it must be administered under a vet’s supervision), support staff, anesthesia and sutures. Male dogs, after a little Benadryl®, receive 1 small injection in each testicle and are immediately up and around. The cost of Zeuterin™ / Esterilsol™? Likely between $4 and $10 per neuter, based on testicular width. The value of saving lives, of course, is priceless.

A Healthier Option

We so often hear the health benefits of surgical castration, which nearly eliminates testosterone. While there are benefits, I was shocked to learn that complete elimination of testosterone actually has a negative impact on the health of a dog’s skin, heart, prostate, liver, skeletal, immune and other systems/organs as cited in a 2007 study by Laura J. Sanborn called Long Term Health Risks and Benefits Associated with Spay Neuter in Dogs. Of course, the importance of hormonal balance makes sense. We’ve simply been taught to ignore it with no alternate neuter option in place. With Zeuterin™ / Esterilsol™, testosterone levels decrease but not entirely, offering healthful benefits that surgical neuters cannot.

The Man Behind the Company

Joe TosiniZeuterin™ /Esterilsol™ was presented at the Helen Woodward Animal Center ACES program on March 31st by Joe Tosini, CEO of Ark Sciences. As Joe spoke, he was clearly excited that his product had just become the world’s first FDA approved sterilant, but I was struck most by his passion and compassion for people and animals.

Joe has long been involved with international humanitarian aid work and learned through immersion that the suffering of human beings and the suffering of animals go hand-in-hand (a hard lesson I too had learned volunteering in Ghana).

Presented with an opportunity to invest in Ark Sciences, Joe felt moved to lead the company, seeking to reduce the horrors of animal overpopulation and human rabies deaths worldwide. He stands firmly behind his product and he is not alone…

When Will Zeuterin™ Reach the US?

By November of 2011, Zeuterin™ / Esterilsol™ will be manufactured in the United States.  If your vet doesn’t carry it at that time, you can contact Ark Sciences to find one in your area who does. Zeuterin™ / Esterilsol™ is already included in Veterinary Pet Insurance Plans with routine care coverage and the UK will see production in 2012.

While new in the US, Zeuterin™ / Esterilsol™ is already partnering with the ASPCA, Veterinarians without Borders, Alliance for Contraception in Cats and Dogs,  US AID Africa, US Army Veterinary Services, Veterinary Universities and more. Having proven effective, safe and virtually painless in 20,000 Mexican dogs with no long term side effects, Zeuterin™ / Esterilsol™ is also being used with great success in India, Bangladesh, Zambia, various countries in Africa, the Dominican Republic, Colombia, for Japan’s Tsunami/earthquake crisis, and the US Army Veterinary Services uses Zeuterin™ / Esterilsol™ to manage canine population in various Pacific Rim Islands. Russia is coming soon.

UPDATE: As of 1.25.2013, the website says:

Our vision is Full Adoption USA by 2015. We are now training veterinarians supplying them with our sterilization product. By mid-2013, it will be ready for sale at a price that will allow them to sterilize up to five dogs for the price of one castration (on average), five times faster, and five times safer. We have other products on the way that will be game changing for other animals.

Bark Out Loud Weekly

Bark Out Loud Weekly Interviews Joe Tosini

I invited Joe to speak with Bark Out Loud Weekly, a short-term project uniting dog experts and dog lovers for informational podcasts and chats. He gave a fabulous in-depth interview with host Mary Doane entitled “Goodbye, Euthanasia?” (mp3).

Joe talks about how long Ark Sciences has focused on lessening the estimated 500,000 roaming dogs in the world, many of whom are friendly community dogs playing with children, transferring rabies to them through friendly licks and ultimately causing 55,000 rabies deaths annually. He talks more about points I raise here too, including the health benefits of chemical castration for dogs and cost benefits to rescue organizations. Listen in, if you’re so inclined. It’s free information!

Zeuterin™ / Esterilsol™ Presentation, Part 1 

(Zeuterin™ wasn’t the name yet. This article was updated 1.25.2013)

Part 1 of the Esterilsol™ presentation at the Helen Woodward Animal Center features Joe Tosini and Dr. G. Robert Weedon, DVM, MPH. To be clear, Dr. Weedon is not an employee of Ark Sciences but he does train on how to use Esterilsol™. His credentials are as follows:

  • Shelter Veterinarian with the Champaign County Humane Society
  • Veterinary Outreach Coordinator with the Alliance for Rabies Control
  • Board Vice-Chair for the Alliance for Contraception in Cats and Dogs


Questions? But Of Course!

Wednesday, I’ll feature the medical side of the story as told by Dr. Weedon. After his powerpoint, he holds an open and frank Q&A with representatives of various rescue organizations. Some of this can be seen on Wednesday and the rest will be posted Friday. Also, during the chat with Ark Sciences at BOLWeekly.com, a question about the impact of Zeuterin™ / Esterilsol™ on behavior arose. Stop by to hear the answer.

This has been Part 1 of a 3 part series


  1. That's awesome news, Kim — best I've heard in a long time.

    When I was doing a story for Your Dog on spay and neuter I read a lot about health problems, especially in males — in females, breast cancer is a concern and spaying does eliminate it. There were also new questions about how extensive the behavioral benefits of castration are. At this point, overpopulation is a greater health issue — if you consider loss of life for unwanted animals the ultimate health problem — but if this became a safe, inexpensive, widespread option, that would be fantastic.

    • Edie,

      You might like part 2 coming on Wednesday. Dr. Weedon addresses the medical/health benefits more extensively, specifically the benefits of spaying before the 1st heat cycle and documented increase in certain cancers for dogs who are surgically castrated. I agree, at this point we need to address strays and overwhelmed rescues. Since results elsewhere look so good, I'm ready to buy stock in this company.

  2. This is fascinating! I am so glad there has been a company working on such a terrific project that will change and save so many lives. A large problem in my part of the world is the current state feral cats. These cats can never be adopted, can never live in a normal home environment. Due to lack of government funding and resources, the cats are left without any protection at all and the problem only gets worse. Individuals and TNR rgroups do what they can but expense is always an issue. This non-surgical, more affordable procedure may be a great solution to a situation that is getting more difficult every single year.

    • Esterilsol has been approved in Columbia for cats so far, Kristine. In fact, during our BOLWeekly chat, the guys from Ark Sciences said it works on all males – so to be careful with where you aim it. LOL.

      All joking aside… Sadly, it costs another million dollars for Ark Sciences to approve for cats with the US FDA but, as I understand it, they are working on it.

  3. This is amazing news for everyone, but especially rescues. I hope we can get this in Peru soon after it is released in the US.

    • Hi, Molly. I know Amazon CARES provides spay/neuter programs in Peru but the need there is just so great. I can't imagine where you start with so many strays as part of the Peruvian culture, yet you have. If Esterilsol can make that job easier, I hope it reaches you soon. You may want to contact Ark Sciences and ask their plans.

  4. Thanks for the suggestion. It is so hard to get drugs into Peru. But this one is worth fighting for!

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