Melatonin For Dogs: Uses, Dosage, & Side Effects

by Richard Walther, DVM
Pawlicy Advisor
Pet Care Blog
Melatonin For Dogs: Uses, Dosage, & Side Effects
Melatonin is a natural supplement that can help dogs combat sleep issues, anxiety, and other conditions. Find out more about the uses, dosage, and side effects of melatonin in dogs.

Melatonin is a naturally occurring hormone known to help with a range of health and mood issues in dogs, including Cushing’s disease, anxiety, and more. But what exactly is melatonin? How does it work, and is it safe for dogs?

In this post, we’re discussing everything you need to know about the uses, dosage, and side effects of melatonin supplements in dogs.

Table of Contents:

Pro Tip: Your vet might recommend supplements or prescription food to help your dog with certain health conditions. With pet insurance, you can get reimbursed for a portion of these products so long as they’re used to treat a covered condition.

What is melatonin?

Melatonin is a hormone secreted by the pineal gland, a small gland located above the middle of the brain. The hormone regulates the circadian rhythm of the body, or our biological alarm clock that tells us when we should sleep and when we need to be awake. As the daylight begins to fade and the night gets darker, the brain signals the pineal gland to increase the production of melatonin, which causes us to feel sleepy in response.

That’s why if the production of melatonin in the body drops, sleep problems often develop. This is where melatonin supplements come into play. As a supplement, melatonin may be effective for helping sleep-related issues but it can also help us and our furry friends relax and relieve stress. It can also help with certain medical conditions.

Bottle of pills and reading glasses on table

Is melatonin safe for dogs?

Melatonin is safe for both humans and dogs. However, if your canine companion suffers from a diagnosed medical condition, it’s important to talk to your vet to ensure that melatonin is a safe option.

Uses of melatonin for dogs

More research is necessary but thus far, anecdotal evidence suggests that melatonin can help with sleep and behavioral issues, adrenal disease, as well as non-allergic hair loss in certain breeds of dogs.


As mentioned before, melatonin helps regulate the body’s sleep cycle. People often use melatonin supplements to overcome sleep issues like insomnia and jet lag.

As our canine companions get older, they can start suffering from sleep-related problems. Melatonin supplements can boost your pet’s melatonin levels, making it easier for them to fall asleep, and stay asleep for longer. In addition, melatonin supplements can help regulate the biorhythm of senior pups with cognitive dysfunctions and help them get a better night’s sleep.


Due to its calming effects, melatonin can be effective in soothing pups suffering from anxiety disorders. This includes pets who suffer from general anxiety, separation anxiety, as well as those who have anxious reactions to loud noises, like fireworks and thunderstorms. Melatonin can also help your pup relax before a potentially stressful experience, like a vet visit or a road trip.


Melatonin can be effective in combating seasonal alopecia, also called flank alopecia. In dogs, this condition manifests through bald patches on both sides of the abdomen. It is not clear how melatonin helps flank alopecia but considering the fact that the potential for severe side effects is low, many owners - in consultation with their veterinarian - decide to give it a try.

Melatonin also helps with Alopecia-X, a non-inflammatory disorder that causes hair loss in some dog breeds. There’s no standard treatment for this condition, but many veterinarians report good results using melatonin.

Cushing's Disease

Cushing's disease is a condition in which the adrenal glands overproduce certain hormones, which results in an increase in cortisol levels. Cushing’s can cause a number of side effects including obesity, lack of appetite, insomnia, and hair loss. The conventional medications for this disease in dogs can also cause severe side effects like diarrhea, vomiting, and kidney failure.

In some cases, melatonin can help alleviate some of the symptoms of the disease. If Cushing’s is caused by a tumor on the pituitary or adrenal gland, melatonin will block the uptake of excess cortisol in the body. Because melatonin is much gentler than traditional medication, many veterinarians may recommend it for dogs where traditional medications have resulted in serious side effects.

Melatonin dosage for dogs

Although available over the counter, when it comes to determining the right dosage of melatonin for your dog, you should always consult your vet.

The dosage will depend on whether you’re using melatonin to treat insomnia, anxiety, or another condition, as well as on your dog’s size and weight. Other factors such as pre-existing conditions should also be taken into consideration, but regardless of the dosage size, you should never give your pet melatonin more than three times a day.

Typically, dogs take melatonin orally in the form of tablets, capsules, powder, or liquid, with or without food. If your dog vomits after taking melatonin on an empty stomach, consider administering future doses with food.

If your dog rejects the tablets or capsules, consider placing them inside some peanut butter. If you’re using liquid or powder, you can add it to a treat, but try to make sure your dog consumes the full dosage.

Some vets might recommend giving melatonin via injection, especially if your furry pal is suffering from Alopecia X. Melatonin is also available in the form of subcutaneous implants. These tiny medical devices are inserted beneath the pup’s skin and slowly release melatonin to keep a steady flow through the bloodstream. For pups with Alopecia X, this slow-release form of melatonin is perfect to stimulate hair growth. Each implant works for about four months and should only be inserted by a veterinarian.

Melatonin starts working quickly (about 30 minutes) and its effects last for about eight hours when given in the correct dosage. Therefore, if your dog uses melatonin for sleep, they should receive it shortly before bedtime.

If you miss a dose, give it as soon as you remember, but if it’s almost the time for the next dose, skip the missed dose and return to the regular schedule. Don’t administer two doses of melatonin to dogs in one setting.

An overhead view of a sleeping dog

Side effects of melatonin in dogs

If melatonin is administered properly and at the correct dosage, there shouldn’t be any significant side effects. It should be noted that melatonin has not been approved by the FDA for use in animals and there hasn’t been sufficient research on its safety and side effects. However, if your veterinarian determines that melatonin is a good option for your pet, it may help your pup with a range of issues with minimal (if any) side effects.

Although rare, side effects of melatonin in dogs include:

  • Cramps and tummy upset
  • Confusion
  • Drowsiness
  • Itching
  • Increased heart rate (tachycardia)
  • Fertility changes
  • Digestive upset
  • Insulin resistance in dogs with diabetes

If you notice any of these side effects, be sure to talk to your veterinarian as they might recommend reducing your dog’s dose or suggest a different course of treatment.

To stay on the safe side, make sure to read the labels on melatonin products as some might contain ingredients like xylitol, an artificial sweetener that can be very toxic to dogs.

Melatonin should not be given to dogs who are allergic to it. Melatonin implants should not be used in pregnant dogs and young puppies. The oral form of the supplement should also be used with caution in pregnant and nursing dogs.

Melatonin overdose and allergic reactions are very rare, but if you’re concerned that you have given your pup too much melatonin and they are experiencing adverse side effects, call your vet.

Pro Tip: If your dog requires emergency veterinary treatment, it often comes with a large bill – and that's where pet insurance comes in to help. With a pet insurance policy in place, you’ll know that you have financial support to help you deal with the unexpected expenses, so you can instead focus on getting your pet the care they need.

Possible drug interactions with melatonin

The following drugs can interact poorly with melatonin: warfarin, benzodiazepines, and succinylcholine. Melatonin can make some medical conditions worse and can also decrease estradiol and cortisol levels.

For this reason, it’s important to let your vet know if your canine companion is taking any medications, supplements, or vitamins.

Key Takeaways

  • Melatonin is a naturally occurring hormone produced in the brains of most mammals. People usually use melatonin supplements to help promote healthy sleep, and some veterinarians recommend melatonin for the same purpose for animals.
  • Melatonin also appears to treat many other health issues in dogs, including anxiety, phobias, alopecia, and Cushing’s disease.
  • Although side effects caused by melatonin are rare, they are possible and for that reason, it is always best to discuss the use of melatonin supplements with your veterinarian before giving any to your canine friend.

Ricky Walther, DVM

About the author

Richard Walther, DVM

Associate Veterinarian - Blue Ravine Animal Hospital

Ricky Walther, DVM, is a small animal general practitioner at Blue Ravine Animal Hospital in the greater Sacramento, California area. Realizing the positive financial and medical impact that pet insurance can provide for pet parents and the profession, he lends support and advice to companies like Pawlicy Advisor that simplify the process of connecting with veterinary financing resources.

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