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Melatonin for Dogs – Safety, Dosage, Prescription & Alternatives

Written by Jay
BsC (Hons) Animal Behaviour & Welfare graduate with a passion for advocating for misunderstood animals.
Published on
Thursday 28 January 2021
Last updated on
Tuesday 9 May 2023
melatonin for dogs
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Melatonin for dogs is a generally safe and beneficial supplement. Naturally made in the body, melatonin is a hormone that regulates the sleep-wake cycle of all animals. As a supplement, your vet may recommend melatonin for treating anxiety, insomnia, hair loss, and even symptoms of Cushing’s disease.

As with any supplement, there are costs and benefits to giving melatonin. Melatonin for a dog is usually safe but extremely high doses may cause side effects. Because of this, it is important to ask your vet for advice before giving your furry friend melatonin.

Is Melatonin Safe for Dogs?

When given properly, melatonin is very safe for dogs. Melatonin is a hormonal supplement for treating restlessness, anxiety, and hyperactivity. You may find that melatonin helps your dog to relax during stressful times. Similarly, melatonin can help to calm dogs with specific anxieties, for example, fireworks and thunderstorms. It can also help your dog to fall asleep, with effects lasting for about eight hours. Because the side effects of melatonin are few, many owners prefer to give their precious pooch melatonin instead of drugs that may cause more harmful effects.

Although melatonin is safe, you must consult with your vet before giving any to your dog. Some medications interact poorly with melatonin, and some medical problems may worsen with melatonin use. Also, melatonin should not be given to dogs who are pregnant or less than 12 weeks old. Melatonin’s effects on seizures are also not well-known yet. To be safe, get professional advice first!

Benefits of Melatonin for Dogs?

Melatonin has several benefits for dogs. When given as directed by a vet, melatonin can help to lessen dog anxiety, Cushing’s disease, insomnia, alopecia, and hyperactivity. Other uses for melatonin include seizure reduction and pain relief.

Dog Anxiety

In a 2017 study of rats, melatonin increased the levels of gamma-aminobutyric acid (GABA) in parts of the brain. Higher GABA levels in the brain give a calming effect and can reduce anxiety symptoms. This is because GABA tells the brain to slow down and relaxes the nervous system. Other medications that treat anxiety, like benzodiazepines, also work by increasing GABA levels in the brain.

As well as directly altering your dog’s brain, melatonin will also help them to sleep better. Sleep disturbances are a key symptom of generalized anxiety, as anxiety can make it difficult to fall asleep and stay asleep. In turn, a lack of sleep contributes to more intense anxiety symptoms. Unfortunately, the best dose for improving dog anxiety is not clear yet. Your best option is to talk to your vet about the best dose for your anxious furry friend.

Cushing’s Disease

With Cushing’s Disease, a dog’s melatonin levels are naturally very low. Melatonin helps dogs with Cushing’s disease in several ways. Dogs with Cushing’s disease of the pituitary gland display hair loss, thin skin, skin infections, and increased appetite. Melatonin can help with hair loss in dogs, making it a suitable treatment for the symptoms of Cushing’s disease.

Most importantly, melatonin for Cushing’s disease helps to block the body’s uptake of cortisol. In pituitary-dependent Cushing’s disease, your dog may have a benign tumor on their pituitary gland, which causes them to produce more cortisol than they need. This chemical helps your pooch to respond to stress, controls their weight, and keeps their blood sugar in check. Too much or too little cortisol can lead to problems. For melatonin treatment to be effective against these symptoms, it should continue for at least four months.


Melatonin for dogs is commonly given as a medicine to treat insomnia. Naturally made in the body, melatonin regulates the sleep-wake cycle and is produced, in darkness, by the pineal gland. Also known as the “hormone of darkness”, melatonin promotes activity in nocturnal animals and sleep in diurnal ones. As a diurnal animal, your pooch’s melatonin production inhibits leptin production at night. By inhibiting leptin, your dog’s ability to feel hunger at night diminishes. This also helps to encourage sleep, thus helping to treat insomnia in dogs.

If your dog struggles to get enough sleep, consider talking to your vet about melatonin treatment to boost their melatonin levels before bedtime. Studies show that melatonin is moderately effective in treating insomnia. In humans, melatonin may increase sleep efficiency by 2 to 3 percent as it increases sleeping time by an average of 13 minutes. The precise effectiveness of melatonin for dogs is not yet known.

melatonin for dog insomnia
Melatonin can be helpful for dog insomnia.


Melatonin is an effective hormone for treating alopecia in dogs. A range of hormones regulate the hair growth cycle, and a disruption to any of these hormones causes hair follicles to reach the telogen, or falling stage, very quickly. Such hormonal disruption can be seen in Cushing’s disease, causing symptoms like thin skin and hair loss. Not only this, but hair follicles have melatonin receptors, which suggests that melatonin plays some role in hair growth. As well as hormonal disruption, hair loss worsens with oxidative stress. Melatonin is a powerful antioxidant with the ability to fight oxidative stress in dogs. An antioxidant works by scavenging free radicals in the body. These are compounds that cause harm when too many accumulate in the body. Free radicals contribute to alopecia because they break down hair follicles.


Similarly to how melatonin helps with anxiety, melatonin can also help to settle hyperactive dogs. Melatonin increases the levels of gamma-aminobutyric acid (GABA) in the brain. GABA creates a calming effect and reduces anxiety symptoms that can contribute to hyperactivity in dogs. This is because GABA tells the nervous system to slow down. However, you must know that not all dogs benefit from melatonin treatment for hyperactivity. Some breeds are high-energy and require lots of exercise to burn through their energy. Other dogs may be hyperactive due to anxiety disorders, territorialism, hyperthyroidism, cognitive decline, or conditioning. Rarely, some dogs experience hyperkinesis, which melatonin alone will not treat. Dogs with hyperkinesis often require help from a canine behaviorist, medication, and environmental changes to manage their symptoms.

Melatonin Dosage for Dogs

The best dosage of melatonin for dogs should be given by your vet. Individual dogs have different needs, and your dog may do better with more or less melatonin compared to another dog. If you miss a dose, make sure to give it to your dog the next time you remember and return to the regular dosing schedule. Do not give your pet two doses or give extra doses to make up for the missing dose.

The dosage of melatonin is usually based on your dog’s weight. Dogs weighing less than 10 lbs may take 1mg per dose. In contrast, a dog weighing between 10 and 25 lbs may take 1.5 mg. For dogs weighing between 26 and 100 pounds, 3 mg is more appropriate. Finally, dogs over 100 lbs may take 3 to 6mg of melatonin for a maximum of three doses per day. If given effectively, melatonin starts working in one to two hours and its effects last for about eight hours.

Melatonin Side Effects in Dogs

Melatonin is generally safe for short-term use in dogs. The side effects of melatonin are usually mild and resolve quickly. Possible side effects include drowsiness, dizziness, agitation, upset stomach, itching, and higher heart rate. Some dogs experience changes in their fertility as well. Some diabetic dogs also develop insulin resistance when taking melatonin. Also, melatonin implants can cause sterile abscesses.

short term melatonin use for dogs
Dog melatonin is safe for short-term use.

Melatonin Alternatives for Dogs

While melatonin is safe for dogs, many owners find themselves looking for alternatives. Depending on what you intend to help your dog with, you may consider CBD oil, omega fatty acids, or veterinary NSAIDs. But which is best for your furry friend?


CBD, or cannabidiol, is a compound from cannabis and hemp. Cannabidiol does not contain delta-9-tetrahydrocannabinol (THC), the compound that would give the product psychoactive properties. This makes it safe for dogs. To date, there are few studies on how this oil affects dogs. We also have anecdotal evidence from pet parents who use CBD to help to relieve neuropathic pain, seizures, and other health problems.

In a study held between 2016 and 2017, there was a significant association between the amount of CBD and the degree of seizure reduction. If your dog experiences seizures as well as anxiety, CBD may be better for them than melatonin, as the effects of melatonin on seizures are not well known. Similarly, in one 2018 study, it was found that 2mg/kg of CBD oil twice daily increased comfort and activity in dogs with osteoarthritis. This is because CBD has anti-inflammatory properties. Many owners also report that CBD helps with anxiety in their furry friends. Make sure that you follow the proper dosage when giving your dog CBD, and ask your vet for some advice!

Omega Fatty Acids

Like melatonin, omega fatty acids may help to reduce anxiety and alleviate some pain and inflammation. Research by Purina suggests that supplementing a dog’s diet with omega-3 polyunsaturated fatty acid may offer anti-anxiety qualities. In these findings, dogs display a reduction in physiological and behavioral signs of anxiety. The signs did not disappear completely but reduced by 40 to 50 percent. Omega-3 fatty acid supplementation is a natural method of decreasing pain and inflammation in dogs with osteoarthritis. Diets enriched with EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) improve some dogs’ weight-bearing and functional activity.


There is no substitute for veterinary pain relief when treating chronic, painful conditions. Non-steroidal anti-inflammatory drugs (NSAIDs) are drugs that relieve pain and inflammation by inhibiting cyclooxygenase (COX) enzymes. They are often given to relieve pain after surgery and to support dogs with chronic painful conditions. You must use an NSAID under the guidance of your vet and follow their instructions carefully. Similarly, you must not give human NSAIDs to your pooch, as these can be fatal to dogs.

Melatonin for Dogs – FAQs

Have any more questions or concerns about melatonin for dogs? Feel free to refer to our Frequently Asked Questions section for more information. If in doubt, always ask your vet for advice.

Is over the counter melatonin safe for dogs?

Your vet may recommend over-the-counter melatonin, but not all types are safe. Melatonin that is fruit-flavored, or comes in a rapid-dissolve tablet form, or a gummy form, is highly likely to contain xylitol. So what’s so dangerous about xylitol?

Xylitol causes two major problems for dogs: liver damage and hypoglycemia. Liver damage can be extensive and rapidly fatal. It is not yet known exactly how liver damage occurs after xylitol ingestion, but even small amounts are enough to cause necrosis. Hypoglycemia develops because the pancreas confuses xylitol with real sugar. This causes blood sugar levels to plummet, causing weakness, tremors, and seizures.

The hypoglycemic dose of xylitol is very small, at only 0.0075 to 0.1 grams per kg of body weight. This means that even small amounts of xylitol cannot be risked when giving melatonin to your dog. If the product lists xylitol as an ingredient, skip it and opt for a safer one.

What is a good alternative to melatonin?

Depending on what you use melatonin for, there are several good alternatives. For stress relief, you may consider CBD oil or omega-3 polyunsaturated fatty acids. Similarly, CBD oil and omega-3 polyunsaturated fatty acids help to treat neuropathic, chronic pain but are no substitute for veterinary treatment. In many cases, veterinary-prescribed NSAIDs are necessary to control the pain and inflammation associated with long-term conditions like osteoarthritis.

Aside from these treatments, you may also consider antihistamines. Diphenhydramine is an antihistamine for treating allergies but is also effective against insomnia and symptoms of anxiety. This drug alleviates tremors and has sleep-inducing properties. Most commonly, diphenhydramine is found in Benadryl. While Benadryl is not FDA-approved for dogs, it is widely thought to be safe and is recommended by vets across the U.S. The usual dosage of Benadryl is 1mg/lb two to three times per day. However, it’s best to check in with your vet before giving your pooch any Benadryl.

Can melatonin hurt dogs?

Because Melatonin is naturally made in the body, it is usually very safe for your healthy furry friend. As well as this, its side effects are normally mild and do not last for long. The most common side effects of melatonin are vomiting, diarrhea, stomach cramps, and tiredness. These side effects tend to resolve within a few hours of taking the melatonin. So, unless melatonin is given in extremely high doses, your pooch is unlikely to become unwell after taking it. Just be sure to only use a melatonin product that is safe for dogs – avoid those containing xylitol and other harmful sweeteners. If in doubt, always ask your vet for advice.

Despite being safe to use, melatonin may have adverse effects on pre-existing conditions. For example, melatonin should not be given to dogs with autoimmune conditions. This is because melatonin stimulates the function of the immune system, potentially contradicting any immunosuppressive medications that your dog is taking. Furthermore, there may be a higher risk of liver problems with melatonin. Over time, the liver becomes less able to metabolize melatonin in the body, but the extent of this is not well-studied. Lastly, the safety of melatonin use during pregnancy is not clear yet. To be safe, avoid giving melatonin to your pregnant pooch where possible.

What happens if a dog has too much melatonin?

Every medicine has an LD 50. This is the lethal dose when 50 percent of subjects would die of exposure. Interestingly, no LD 50 has been found for melatonin! Even extremely high doses have not proven fatal for animals. However, this does not mean that melatonin cannot be harmful in excess. In extremely high doses, melatonin may cause paranoia, confusion, hallucinations, anxiety, and dizziness in humans. Because of these risks, it is important to stick with the dose that you normally give to your pooch!

Make sure that you know the signs of a melatonin overdose. Accidents happen, and you must be prepared for this. If your dog shows signs of a melatonin overdose, get in contact with your vet right away. You may also contact the Pet Poison Helpline for quick advice.

Can melatonin cause seizures in dogs?

The effects of melatonin on seizures are not completely understood, but a melatonin overdose may cause seizures. At the same time, there may still be a small risk with smaller doses of melatonin. But why is this? To begin, people with epilepsy have lower melatonin levels than average. These lower melatonin levels might contribute to seizure activity. Conversely, melatonin levels increase dramatically during a seizure in humans. Being able to establish a balance that reduces seizure activity is thus quite difficult, and so, the relationship between melatonin and seizures in dogs is less understood. In one study, it was found that melatonin concentrations were not significantly different between dogs with and without seizures. As a result of this, the effects of melatonin supplements on seizures seem to vary.

What we do know for sure is that a melatonin overdose may cause seizures. While melatonin is not usually dangerous, extremely high doses can cause side effects such as vomiting, diarrhea, anxiety, and seizures. In the event of an overdose, make sure to call your vet right away.

Melatonin for dogs is safe when given in small doses to a physically healthy dog. However, you must be careful to not overdose your pooch on melatonin. While melatonin is not dangerous enough to cause death, it may cause seizures, anxiety, restlessness, and other problems for your pet.

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