Melatonin for Dogs: A Comprehensive Guide

By Chelsea Hunt-Rivera / May 7, 2018
melatonin for dogs

If you’ve suffered from jet lag related insomnia, you’ve inevitably heard of Melatonin as a cure for a broken sleep pattern. But Melatonin for dogs? Dogs don’t get jet lag. Well, not as far as we know. So why are more and more pet parents considering giving their dogs Melatonin?

Turns out there is a long list of reasons why people and even veterinarians are turning to this supplement to treat dogs. What humans have been taking as a sleep aid turns out to have a range of benefits for dogs.

The catch is, that we don’t know all that much about the way Melatonin works, and even less about the side effects and safety of using it on dogs and other pets. So why do so many pet parents swear by it? The few studies that do exist on the use of Melatonin for dogs, all have the same findings: It seems to be safe, and it seems to successfully treat dogs with anything from anxiety to hair loss.

Melatonin is a great alternative to many harsh, chemical drugs used to treat dogs with a range of medical conditions.

melatonin for dogs

What is Melatonin for Dogs?

What is Melatonin?

Melatonin is most commonly (and historically) referred to as a “neurohormone” found in animals. Over the last decade, studies of the substance have intensified, and it turns out that the term “neurohormone” doesn’t quite cover it. Scientists have found the presence of melatonin in everything from fungi and bacteria, to plants. None of which have the need for any things “neuro”.

According to the National Center for Biotechnology Information (NCBI): “Melatonin is a natural occurring free radical scavenger and an inducer of antioxidant enzymes…”. It seems to be so much more than simply a “neurohormone” found in animals. There is a lot we still don’t know about it, but we can apply what little we do know to dogs as well as humans.

Melatonin is a neurohormone that is produced in the pineal gland in the brain of humans (and dogs). The pineal gland’s job, among other things, is to help regulate our circadian rhythms. i.e., our sleep-wake cycle.

The Melatonin we (or our dogs) ingest, makes its way into the bloodstream and then to the brain. Once it’s reached the brain, it crosses the blood-brain barrier and then gathers in the central nervous system (CNS) where the naturally occurring Melatonin also gathers. It definitely has a big role in regulating our sleep patterns, but scientists are discovering that it does more than that.

The Melatonin that accumulates in the Central Nervous System actually has protective properties. When the CNS is compromised, the Melatonin scavenges for free radicals and stimulates the production of antioxidant enzymes.

There is still a lot to learn about the way Melatonin works, but what we do know, is that natural Melatonin production slows down when it’s light and increases in the dark. It plays a significant role in why nocturnal animals are awake during the night, and why diurnal animals function during the day. It adjusts our sleeping patterns when the seasons change. When the days become longer and the nights shorter, and vice versa.

Melatonin also has sedative properties which is why people take it to recover from jet lag. For example, if you’ve been travelling and suddenly you’re in a time-zone with reversed day and night, taking Melatonin can trick your brain into thinking it’s its natural night time. It may actually be your 10 AM, but the Melatonin tells yours brain it’s 10 PM, and time for sleep.

Melatonin is collected from animals, but the more sustainable (and safer) method of taking it is in it’s synthetically produced form. In the US and in Canada it is available as an over the counter drug, in powder, tablet, capsule, or liquid form.

Is Melatonin Safe for Dogs?

melatonin safe for dogs

The FDA has not approved Melatonin as safe for dogs. But that is not stopping vets and pet parents from giving it to their four-legged furry friends. Melatonin seems to be perfectly safe (and beneficial) for dogs. As with any other supplement or drug, you should ask your veterinarian whether they think giving it to your dog is a good idea, as well as how to safely give it to your dog.

Reports of negative side-effects of Melatonin in dogs are few and far between. People opt for Melatonin because it is so seemingly safe, and a far more natural approach than dog tranquilizers and other medications.

Melatonin products designed specifically for dogs are readily available on the market. Those should always be your first go-to. Some products meant for humans often have ingredients which are toxic to dogs. Always check the label for ingredients that are harmful to dogs. Xylitol is one such toxic ingredient. Many Melatonin products contain the artificial sweetener Xylitol.

Of the little we know about the safety of Melatonin for dogs, a few things are clear: It is not safe for dogs meant for breeding purposes, for dogs with certain hormonal imbalances, dogs with diabetes, pregnant dogs, or young puppies. This is why it is always necessary to discuss with your vet whether something is safe to give to your dog.

Melatonin Benefits for Dogs

melatonin benefits in dogs

Anxiety in Dogs

Melatonin is a great alternative to dog tranquilizers and other calming medications such as antihistamines. Its sedative properties have shown to be very successful in reducing the anxiety levels of many a doggo with separation anxiety.

In an ideal world, every doggo would feel calm and safe all the time. Some dogs, despite their parents’ best efforts simply have a nervous disposition. Melatonin gives these dogs a better quality of life. Other calming medications may ease a dog’s anxiety, but they will often make dogs feel drowsy and uncoordinated. Melatonin doesn’t have that effect. It calms them down without the negative side-effects of harsher chemical medications.

If you know that your dog has a stressful situation coming up, Melatonin should sort them out. For some dogs every day is a stressful situation. They get separation anxiety every time their humans go to work or leave them alone at home to go out for the evening. Separation anxiety can have a big effect on the quality of life of these poor pups. Melatonin can help.

Some dogs are fine with being left alone but become anxious in situations where they have to leave the house. They get stressed out when they are forced to go in the car or on a plane. Perhaps they hate going to the groomers, or to the vet. These are all anxieties which Melatonin can help mellow out. In situations where you know something is coming up that will cause your dog to become anxious, you can give them Melatonin to ease that anxiety.

Noise Phobias

Melatonin can help calm dogs with noise phobias. Fireworks. Sirens. Vacuum cleaners. Loud noises simply terrify some dogs. Melatonin can help settle them in loud situations without the negative side-effects of other calming medications. After all, you want to help your dog calm down, not knock them out every time there’s a thunderstorm!

Thunderstorm Phobia

dog afraid of thunderstorm

Scientists and some veterinarians are still trying to pinpoint the exact cause of why thunderstorms terrify dogs. Apart from the obvious noise phobia that accompanies the storms. They are studying the effect that the drop in Barometric pressure during thunderstorms has on dogs. We don’t really feel an increase of static electricity around us during a thunderstorm, but it seems as though dogs experience a build-up of static electricity in their coats. Thunderstorms would terrify people too if it meant that the entire world around them, and everything they touched was zapping them with shocks of electricity.


Some pet parents have been treating their epileptic dogs with Melatonin and have reported that their dogs have had less seizures than before they got the supplement.

Cushing’s Disease

Cushing’s disease is caused by a tumor either on the pituitary glands or the adrenal glands. These tumors cause the production of excessively high cortisol levels (the stress hormone). Too much cortisol is very stressful on a dog’s system. In cases where dogs have benign pituitary tumors, a combination of Melatonin and HMR Lignans has been quite successful in treating the disease. The Melatonin actually inhibits the body’s ability to take up excess cortisol. Less cortisol is a very good thing for a dog with Cushing’s Disease. It means that the dog’s entire system is under less stress, and not in constant “fight-or-flight” mode.

Apart from the fact that the Melatonin inhibits the uptake of excess cortisol, it is a lot easier on the dog’s system than the chemical alternatives. Most medications given to dogs to treat Cushing’s disease come with a list of harsh, negative side-effects, and can lead to a whole new range of medical complications.

Seasonal Alopecia

Also referred to as Flank Alopecia, this is a condition which causes hair loss on either side of a dog’s belly. This Alopecia usually recurs each spring or summer.

Nobody knows the exact cause of Seasonal Alopecia, but it is believed to be caused by a dog’s body having difficulty to keep up with the changing of the seasons. Light inhibits Melatonin production, so as the days grow longer, and the nights grow shorter, more light means less Melatonin.

Some pet owners swear by Melatonin to treat Seasonal Alopecia. By giving their dogs additional Melatonin, the idea is that it will equalize the dip in Melatonin levels and help their dogs keep their coats at the turn of the seasons.

The science is not there to back up this theory, but considering how rare and mild Melatonin side-effects are, it’s probably worth a try! Your dog literally only has to gain from trying Melatonin.

Canine Cognitive Dysfunction

Canine Cognitive Dysfunction (CCD) is similar to Alzheimer’s disease or dementia in humans. It is quite common in older dogs. As they age, their cognitive functioning begins to deteriorate. It really is heartbreaking to see, because they become more and more confused. They have trouble remembering or recognizing people or places, or have trouble seeing and hearing things. Two of the most common symptoms of Canine Cognitive Dysfunction are an increase in anxiety levels, as well as a disrupted circadian cycle (a.k.a. the sleep-wake cycle).

Enter Melatonin! And not only because of its wonderful sedative properties. Melatonin can add real value to the treatment of a condition in which the brain is deteriorating. Remember how Melatonin has neuroprotective properties? When the Central Nervous System is compromised, Melatonin can actually help to prevent the loss of neurons.

And then there are those sedative properties. Melatonin supplementation can help ease the anxiety and increased stress levels of a dog with Canine Cognitive Dysfunction. It can also help them to regulate their sleeping patterns, because Melatonin after all, is what tells the brain that it should be waking up or shutting down for sleep. The problem for dogs suffering from Canine Cognitive Dysfunction is not so much that they suffer from perpetual insomnia, it’s more that their bodies simply struggle to maintain any regular rhythms. Their brain simply can’t communicate to the body what it needs to do. Depending on the dose, Melatonin could tell your dog’s brain for a good 8hrs that it is time to rest.

Melatonin Dosage for Dogs

melatonin dosage for dogs

When prescribing Melatonin, most vets recommend that a dog starts with the lowest dose and gradually increase it to see how the dog reacts to it. Although there isn’t too great a risk that a dog won’t react well to the supplement, it’s better to be careful. Especially considering how little we know about this supplement’s safety and side-effects.

The size and weight of a dog determines the dosage of Melatonin they need. It also depends on the condition that you are treating.

The general rule of thumb for Melatonin dosage is as follows:

  • Dogs weighing under 10lbs: 1mg
  • Dogs weighing between 10lbs and 25lbs: 1.5mg
  • Dogs weighing between 26lbs and 100lbs: 3 mg
  • Dogs weighing over 100lbs: 3mg – 6 mg

Your vet will be able to tell you how much Melatonin to give your dog, as well as how often they could (should) receive a dose. The dose will be occasional for dogs being treated for anxiety. But for dogs being treated with pre-existing medical conditions such as Seasonal Alopecia or Cushing’s Disease, chances are you’ll be giving your dog regular doses of Melatonin as part of the treatment plan. There are even vets that insert Melatonin implants into their canine patients to prevent Melatonin levels from ever dipping too low.

How Long Does Melatonin Last in Dogs?

duration of melatonin in dogs

The Melatonin enters a dog’s bloodstream quite quickly after they’ve taken a dose, but you can expect to start seeing its effects anything from 10 minutes to 15 minutes after giving it to your dog. The period for which it lasts varies depending on the treatment plan.

There are a couple of factors that influence how long Melatonin works in dogs. A dog’s size, weight, metabolism, the amount of water they drink, but most importantly: the dosage.

The higher the dose of Melatonin, the longer it will last in a dog. A dog receiving the occasional dose of Melatonin to treat severe anxiety will be much higher than that of a dog who gets regular doses to treat Seasonal Alopecia for example. In a dog with Canine Cognitive Dysfunction, where they are getting the supplement to help them regulate their sleep patterns, the dose will be quite high and can last for up to 8 hours.

Melatonin Side Effects in Dogs

melatonin side effects in dogs

The bad news: there have not been many studies on the safety and side-effects of Melatonin for dogs. The great news: Many vets and people have been giving their dogs Melatonin and there have not been many reports of negative side-effects.

As with anything else that our beloved fur kids consume, there is always a risk of adverse side-effects. What’s wonderful about Melatonin (and this may have much to do with its natural properties), is that it really does seem relatively safe and risk free.

If your vet has given you the go-ahead, then there is not reason why you shouldn’t give it to your dog. But ONLY, if your vet has given you the thumbs up!

Melatonin is not safe for all dogs. One of the side-effects of the supplement is a change in fertility. This means Melatonin is not safe for breeding dogs. That also rules out any pregnant or lactating mama dogs, who rely on those hormones!

Melatonin may also have some negative side-effects on dogs with certain pre-existing medical conditions. For example, Melatonin causes insulin resistance. Diabetic dogs have enough trouble with their insulin levels as it is. Melatonin is not for these doggos!

Here are some of the possible side-effects (as rare as they are) that a dog might get from taking Melatonin:

  • An upset stomach
  • Reduced sex hormones (which is why it’s not a good idea to give it to breeding dogs)
  • Irritated and itchy skin
  • Increased heart rate (i.e. Tachycardia which is a type of Cardiac Arrhythmia)
  • Insulin resistance (somewhat problematic for dogs with diabetes!)
  • Confusion (some dogs may be more sensitive to Melatonin’s sedative properties than other dogs)

If your dog isn’t a good candidate for Melatonin, CBD for dogs is a fabulous option with virtually no side effects. When it comes to good sleep, CBD is also great for humans as well…

Melatonin Overdose

Too much of anything can have potentially dangerous consequences. Melatonin may be relatively safe in (vet) recommended doses, but if your very good dog made a very bad choice and ate all of it, you need to get them to a vet immediately.

Of the few Melatonin overdoses on record, the most common signs are:

  • Seizures
  • Vomiting
  • Lethargy (You’ll be able to tell the difference between a dog who is mildly sedated, and one that is almost comatose)
  • Confusion 

Being a responsible pet parent can be hard. Making an educated choice of what to give your dog has never been more time and energy intensive. Let’s say you want to know whether garlic is good or bad for your dog. You have to do your homework, so you spend an evening reading all the articles. You go back and forth between the likes of “Garlic Will Kill Your Dog” and “Garlic Is the Best Thing You Could Feed Your Dog”. So how do you make sense of it all?

With garlic, there is a pretty popular notion that it will kill your dog, so it may be best to avoid it. With Melatonin however, the risk factors are so incredibly low and rare, that you don’t have to take a stance “For” or “Against” it.

Dogs can benefit massively from Melatonin supplementation, so why not give it a try? The benefits outweigh the risks tenfold, which is why so many vets and pet parents advocate the use of it so eagerly. If it doesn’t work for your pup, that’s OK. But if it does, you will be doing them a favor by giving them Melatonin instead of other harsh medications that do come with their own long list of cautions and negative side-effects. It really is worth a try.


Can you define Melatonin??

Could my dog have an adverse reaction to Melatonin?

Can Melatonin help my anxious dog?

How much Melatonin should I give my dog?

How long will it take for the Melatonin to leave my dog’s system?


About the author

Chelsea Hunt-Rivera

Chelsea Rivera is a Dedicated Pet Parent who loves to create amazing content for pet owners and is helping change pet wellness as the Head of Content for