Suprelorin Implants For Dogs

two chocolate labs

There is a growing interest in Suprelorin implants for dogs. Contraception is something that’s on the mind of many dog owners.

The subject of castration presents a dilemma for many of us.

Whether we’re trying to prevent unwanted pups, or moderate behavior, surgically removing a part of your dog can feel like a huge decision to make.

Recently, we’ve been presented with more options to solve this. Temporary and reversible contraception techniques have been becoming more commonplace.

With treatments available that claim to produce the same results as castration, with none of the permanence and invasive surgical procedures, we might get excited.

But should we be so quick to trust these methods? How do they work, what are their benefits, and are their side effects?

In today’s article we’re going to look at one of these products, the Suprelorin implant for dogs.

Suprelorin Implants For Dogs – What Are They?

A Suprelorin implant is a capsule that placed under the skin and that slowly releases a hormone that affects a dog’s fertility.

Hormone implants are not new.

We might be more familiar with the idea of contraceptive implants in humans, but they now exist for dogs too.

Which dogs are given Suprelorin?

In humans these kinds of products are usually aimed at females, but with Suprelorin implants for dogs, the recipient is normally male.

The hormone affects both male and female dogs. Three potential uses for female dogs are induction of estrus – in the short term, Suprelorin brings female dogs into season, , contraception (with prolonged use) and treatment of incontinence in spayed females.

The most common target for the drug however, is adult male dogs as the implant renders male dogs temporarily infertile

Why is Suprelorin given to male dogs

There are a few reasons why male dogs might be given Suprelorin, but the main aim is usually to prevent fertility, or to change the dog’s behavior.

At one time, castration was almost universally believed to improve a wide range of behaviors in male dogs. Including aggression which was thought to be linked to the hormone testosterone.

However, a 1997 study found that only a third of castrated dogs showed any noticeable change in behavior for the better. And a number of recent studies have called into question the traditional views on castration reducing aggression (you can find some of them here )

Some studies have even shown that castration may make aggression worse. It’s thought that this is because testosterone is a confidence building hormone, and much aggression in dogs is related to fear, rather than to masculine bravado.

Suprelorin for dogs has the benefit of offering a ‘test run’ to see how castration might affect a dog before removing his testes surgically and permanently.

What is in Suprelorin for dogs?

The active ingredient in Suprelorin is deslorelin.

This compound was originally marketed by a company called Peptech

But the most popular current product to use deslorelin is the Virbac superlorin implant.

Where can we get Suprelorin?

At the time of writing and despite considerable testing, Suprelorin does not yet seem to be available for dogs in the USA.

A version is available for ferrets, but as of yet not for pooches.

There has been some research into a Suprelorin implant for cats, but it’s use is not nearly as widespread as in dogs and ferrets.

Suprelorin implants are available for male dogs, however, in Australia, New Zealand, and throughout the much of Europe.

How do suprelorin implants for dogs work?

The Suprelorin implant hormone for male dogs manages to mimic castration. It does this by impersonating the naturally occurring hormone gonadotropin.

After an initial increase or ‘flare up’ of two important hormones LH and FSH, in response to Superlorin, the gland which controls the production of these hormones becomes ‘desensitised’ and effectively ‘gives up’.  This in turn causes the production of testosterone to fall significantly.

As a result the dog stops producing sperm.

Although not nearly as commonplace a treatment, the Suprelorin implant also has the potential to be used on female dogs. But the initial flare up caused by the deslorelin is a problem in female dogs because it brings them into season.

So for the time being, this implant is almost exclusively for males.

How quickly does the Suprelorin implant work

Deslorelin is released gradually into the dog’s blood stream as soon as the implant is placed under the skin.

The contraceptive effect of the drug does not happen straight away, and the implant may need to be in place for 6 weeks before it’s fully effective.

This delayed start is different to the more instant effect of castration, but doesn’t seem to be any cause for concern.

A dog with an established Suprelorin implant is much less likely to try and mate, due to the lack of testosterone. Even if this dog did mate successfully, the chance of it resulting in a pregnancy is incredibly low, due to the inhibited sperm production.

It’s worth pointing out though, that Suprelorin implants for dogs are not given to males before puberty. It’s not that it would necessarily harm them, although you would expect a lack of testosterone to have an effect on a male dog’s development, it’s just that we don’t really know what would happen.

Let’s take a look at how long you can expect a Suprelorin implant to remain effective for.

How long will a Suprelorin implant last?

The length of time a Suprelorin implant will be effective for is determined by the dosage. As the implant steadily releases this contraceptive into the bloodstream, it only stops working when the supply runs out.

Your vet will discuss dosage based on how long you want the implant to affect your dog. A Suprelorin 4.7 mg implant for dogs, for example, will last about 6 months.

If your dog receives a 9.4 mg implant, the length of time his testosterone will be inhibited will be 12 months.

The 4.7mg implant seems to be more popular.

Over the course of 6 months you should get a pretty good idea of how your dogs behavior has changed, and if castration is the right decision.

Alternatively, your dog may be being kept with an un-spayed female dog for a period of time, and might be all you need to prevent any unwanted puppies.

So, we know what Suprelorin implants are trying to do, but are there any unintended side effects?

Suprelorin implant side effects

Side effects are a fact of life, no matter what we’re trying to treat. Suprelorin is no different and we should be prepared and understand the potential risks.

The most obvious side effects are the ones that would normally come from the act of castration.

The resultant drop in testosterone could cause a change in your dog’s behavior.

It might for example, result in a less confident dog. This loss of confidence can cause fearfulness or anxiety.  Which in turn can result in a dog becoming stressed or aggressive.

If you’ve noticed a significant decline in your dog’s confidence after receiving a Superlorin implant, it’s important to discuss this with your vet. If you are observing signs of nervousness which results in aggression  you might need some help from form your vet in managing your dog for the duration of the treatment.

Remember that ‘flare up’ we talked about as the initial effect of deslorelin. Well this happens in male dogs too. This means that Suprelorin has the potential to make your dog more fertile for a short period after implantation.

A 2012 study found that some of the dogs tested had a higher sperm count in the weeks leading up to the eventual decline.

You might assume that Suprelorin implants would have some sort of effect on a dogs fertility long term, but there’s no evidence to suggest this is the case. You can expect fertility to return to normal after the implant has run it’s course.

Slight changes to your dogs appearance are possible as testosterone is a key factor in how the body generates and maintains muscle.

The site of the implant will usually be rather sore for about two weeks. At this time inflammation can occur and the area might feel hard to the touch.

This swelling can persist for up to three months, but should eventually go down. If you’re concerned at all about the site of the implant not looking right, it never hurts to talk to your vet.

Every dog will react differently, and some may have particular problems with the implant being under their skin.

So if after reading all this, you are hoping that your vet might be able to treat your dog with Suprelorin, you might be wondering how much you could expect to pay for a Suprelorin implant.

Suprelorin implant cost

There are two main factors involved in the cost of Suprelorin for dogs; the actual cost of the implant, and the vets bills on top of it.

Because of the amount these can vary country to country, state to state, and even clinic to clinic it’s very hard to make a reasonable estimate about how much you will pay.

Suprelorin for dogs - are these hormone implants right for your dog?In the UK prices can range from anywhere between £100 and £300, depending on the dose of the implant and also on your own vet and how much they charge for their time.

The figures in Australia are similar in AUD.

It’s worth pointing out that, if your vet has said that Suprelorin might be right for your dog, it could end up saving you money.

However expensive the procedure is at your local clinic, it will definitely be less expensive than raising unwanted puppies if you have a female dog in the house as well.

Suprelorin implant for dogs – a summary

Castration in male dogs is usually undertaken to both

  • Prevent reproduction
  • Improve behaviour

If your main aim is to prevent your dog from breeding, Suprelorin can give you a glimpse into how neutering will affect their personality. This might not be something we even thought about if our main concern is limiting the potential to breed.

If the results are not what you had hoped, you can then look at alternatives such as physical separation from female dogs in season.

If your dog lives with a female dog, and you don’t like the effect that the Suprelorin has on his personality, you may want to consider neutering your female instead.

Surgical castration is an excellent and permanent way to prevent your dog making puppies, but we now know that it may be less effective at improving behavior. Results will vary from dog to dog

In a dog that is already showing signs of nervousness for example, an implant that causes a profound drop in his testosterone levels could potentially make matters worse.

What Suprelorin claims to deliver is the same results as castration, but with none of the permanence.

With this implant we can in essence ‘test drive’ a castrated dog without needing to make the absolute decision. Using this method owners can decide whether the permanent solution is a good decision.

It’s important to bear in mind that, with regards to the smaller dosage, these effects will only last 6 months.

All in all, Suprelorin appears to do what it says on the box. By temporarily stalling testosterone production, you get a dog that is infertile for a while and a chance to assess the dog’s  behavior in the absense of testosterone.

If you think that this might be the right treatment for your dog, it’s time to have a chat with your vet

What’s your experience with Superlorin? Let us know in the comments below.

References and further reading:

Suprelorin Vibrac UK

Fontaine E. et al.Induction of fertile oestrus in the bitch using Deslorelin, a GnRH agonist. Theriogenology 2011

The Labrador Handbook by Pippa Mattinson

Semen Quality and Onset of Sterility Following Administration of a 4.7-mg Deslorelin Implant in Adult Male Dogs S. Romagnoli

Nonsurgical methods of contraception in dogs and cats: Where are we now? M. Cathey, M. A. Memon

Effects of castration on problem behaviors in male dogs with reference to age and duration of behavior. J. C. Neilson et al

European medicines Agency Suprelorin

Clinical Use of Deslorelin for the Control of Reproduction in the B*tch S. romagnoli et al

Suprelorin (deslorin acetate) for male dogs ACC-D

Adams V, BSc (Agr) DVM MSc PhD MRCVS Attitudes to and opinions of neutering in dogs: Results of a Canine Reproduction Survey of Veterinary Surgeons. Presented at BSAVA 2016

Nielson et al. Effects of castration on problem behaviors in male dogs with reference to age and duration of behavior. Journal of the American Veterinary Medical Association.


  1. My 8yr old Rottie boy had the implant to reduce his testosterone as the vet said this could be a contributing factor to his anal cancer. I did not want him castrated as I have his litter brother who was also entire in case this upset the balance between them. He was a very well balanced male with no issues and there was no change in his behaviour in general or with his brother or his brother with him. Sadly six months after the implant the cancer got the better of him and he had to be pts.

  2. I have a question,stay rests of the suprelorin in the body of my dog after the chip ist working not anymore?

  3. I treated my Samoyed Male with the 6 month Suprelorin implant. As you state in your article, it didn’t seem to have much effect for around 6 weeks, and then there were signs of it kicking in. For the duration of the 6 months and for a good while longer (I would say up to at least 10 months) he was a calmer and more balanced dog and very focused when competing at Dog Agility shows. His tendency to mount was markedly reduced and he was not quite as hyper as he usually is. He is a bit of an ‘over the top’ dog normally and there was a small but noticeable reduction in his ‘look at me’ approach to other dogs. His testicles shrank to the size of hazelnuts and showed no sign of returning to normal for around 11 months. Now for the downside. Since getting back his full quota of testosterone his behaviour has become much more ‘out there’ than ever. I now have to walk him on a long leash on certain walks because of his tendency to disappear off in search of other dogs and completely ignore his recall training. He is now hugely competitive with male dogs both neutered and unneutered but will happily accept a telling off from a bitch and then leave her alone. He plays with some bitches and very occasionally with a male but mostly he is just very determined to mount the males and will not give up so that occasionally a fight starts. I assume this behaviour is due to a huge rush of testosterone that he brain seems unable to process. Also I should add that whilst on Suprelorin his had many moments of showing rattiness to other dogs, especially to younger dogs. Not out and out aggression but just touchiness and growling. I am hoping to get a bitch puppy shortly and am now unsure if I should treat him again with Suprelorin and risk possible rattiness with the puppy, or have him permanently neutered which may have the same effect. Samoyeds also tend to grow very thick coats when neutered and this is not something I want. Also they gain weight, and putting him on a permanent diet Is not something I relish (he gets loads of exercise). Any thoughts would be welcome.

  4. Lucy, there are no citations in the references section. Citations look like this:

    Neilson JC, Eckstein RA, Hart BL. “Effects of castration on problem behaviors in male dogs with reference to age and duration of behavior.” J Am Vet Med Assoc. 1997 Jul 15;211(2):180-2.

    I am not saying that to be a jerk. There are thousands of medical journals, and some (like JAVMA) have published thousands of issues. It’s very often necessary to have more information than you provided in your references section to track down a specific study that one is interested in reading.

    Finally, what you linked to in the text wasn’t “some studies” – it was a summary of a masters thesis. When the data that thesis was based on was analyzed by actual scientists the results were considerably different.

  5. “Some studies have even shown that castration may make aggression worse.” Could you please provide citations for these studies? I try to keep current on behavioral research but I am not aware of any such studies.

    Also, I very much wish that you provided actual citations for your references. It seems disingenuous that you don’t.

    • Hi Dan, You seem to have missed the references section at the bottom of the article – but I have now added a link directly into the text too so that the scientific paper is even easier to locate. Hope you find it interesting.