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Melatonin for Dogs: Uses, Dosage, & Side Effects

Melatonin is a hormone supplement used to treat insomnia in humans and is commercially available as Regulin®, Circadin®, and other brand names. This supplement is also used as an adjuvant for dogs that suffer from behavior disorders, sleep disorders, and alopecia (non-allergic hair loss).

Because dogs have a similar circadian rhythm to ours, their wake patterns follow a diurnal sleep rhythm. They are more active during the day and sleep during the night.

Like us, dogs can have sleep problems. Sleep disorders in dogs can occur as a result of cognitive problems (behavioral disorders) or chronic pain.

It is not wrong to ask yourself if you can give your dog melatonin, considering this is a natural hormone (produced by the body).

In this article, you will find information about melatonin for dogs, if melatonin is safe for dogs, what dose of melatonin a dog can take, melatonin side effects, and more.

What Is Melatonin?

Melatonin is a natural hormone produced in the brain and is derived from serotonin (the happiness hormone). The most important role of melatonin is to initiate and maintain sleep. It can be found in some foods and supplements.

Melatonin is also known as the sleep hormone and is mainly produced by the pineal gland in the brain. It can also be produced in the bone marrow, leukocytes, gastrointestinal tract, retina, etc.

It has many roles in the body but its main function is to maintain the circadian rhythm (the body’s biological clock). Melatonin “tells” the body when to sleep and when to wake up.

The pineal gland releases melatonin at night and blocks its production during the day.

Melatonin is found in some foods but also in the form of supplements. It can be safely administered in the short term to induce sleep in both humans and pets.

What Is Melatonin

What Are Melatonin Supplements?

Melatonin supplements are made in pharmaceutical laboratories and have the same role as natural melatonin.

Melatonin supplements for dogs can be purchased from pharmacies (for humans) or the vet’s office (for pets).

Melatonin supplements are used as an adjuvant in the following cases:

  • Jet lag
  • Delayed sleep-wake phase disorder
  • Sleep disorders in children
  • Anxiety before and after surgery[1]

Use of Melatonin for Dogs

Melatonin is used to induce sleep, treat various behavioral disorders, and for alopecia in dogs. Many owners choose to administer their dogs’ supplements instead of drugs as they can contain too many chemicals and have devastating side effects.

Melatonin supplements work as a sedative by supplementing the naturally occurring neurohormone.

Melatonin for dogs is used for:

  • Anxiety (including separation anxiety)
  • Storms and fireworks phobias
  • Hyperactivity
  • Restlessness
  • Alopecia

You should not give melatonin to your dog before consulting the veterinarian. Melatonin can react poorly with select drugs and worsen some medical conditions. It also poses risks for puppies and pregnant dogs.

dog visiting a vet clinic

Is Melatonin Safe for Dogs?

Melatonin is a safe supplement for dogs as long as you contact your veterinarian beforehand. Although rare, melatonin can have various side effects and worsen other diseases. Melatonin poses a risk to puppies under 12 weeks and pregnant or lactating females.

According to ASPCA (the American Society for the Prevention of Cruelty to Animals), melatonin is safe to administer to dogs.[2]

Although the side effects and safety of melatonin in dogs are not well studied, veterinarians prescribe it for various medical conditions.

Due to the lack of studies, melatonin should be avoided in:

  • Puppies under 12 weeks
  • Pregnant female dogs
  • Lactating female dogs

The reasoning is that the introduction of an external substance can disrupt the natural functioning of the dog’s organism. Studies show that after giving melatonin to dogs for 28 consecutive days, melatonin can alter the serum sex hormone concentrations (estradiol and testosterone).[3]

Even if melatonin is safe for dogs and you can purchase it over-the-counter, always discuss it with your veterinarian first.

Is Human Melatonin Safe for Dogs?

Human melatonin supplements can be given to dogs to treat various medical problems. Keep an eye out as some melatonin products can contain xylitol. Xylitol is an artificial sweetener that is toxic to dogs. 

Symptoms for xylitol poisoning in dogs include:

  • Vomiting
  • Decreased activity
  • Weakness
  • Dizziness
  • Incoordination
  • Collapse
  • Seizures

If you plan to give melatonin to your dog, discuss it with your vet before administering it. If you give your dog too much melatonin at once, overdose can occur.

Is Human Melatonin Safe for Dogs

Side Effects of Melatonin in Dogs

Melatonin side effects in dogs are not studied in detail, but most dog owners report minimal and rare adverse reactions. If your dog over-consumed melatonin, you can see the symptoms of overdose.

Melatonin’s side effects in dogs are not well studied. In humans, melatonin presents several risk factors.

Melatonin is not suited for people that suffer from kidney or heart disease.[4] You should use melatonin with caution if your dog suffers from any of these conditions.

Melatonin should stop working after 24 hours. Dogs that suffer from liver diseases can experience its effects longer than this.

Although the melatonin’s side effects are rare and minimal, they include:

  • Gastrointestinal disorders – vomiting, diarrhea, stomach cramps
  • Lethargy
  • Drowsiness
  • Changes in fertility
  • Itchiness

Symptoms of a melatonin overdose include:

  • Vomiting
  • Diarrhea
  • Incoordination
  • Drowsiness
  • Itchiness
  • High blood pressure
  • Fast heart rate
  • Seizures

Related: Can Melatonin Kill a Dog?

sick dog on vet clinic

Melatonin Interactions With Other Drugs

Although there aren’t many studies performed on melatonin for dogs, few drugs interact with it.

The drugs that can interact with melatonin are:

  • Warfarin (anticoagulant)
  • Benzodiazepines (sedative medication)
  • Succinylcholine (skeletal muscle relaxant)

General Guidelines for Using Melatonin in Dogs

Melatonin is used to treat various medical conditions in dogs, such as behavior disorders, sleep disorders, and alopecia. This supplement is prescribed by the vet as it can have side effects or interact with other drugs.

Vets all over the world use melatonin to treat or aid the following medical conditions:

  • Insomnia
  • Separation anxiety
  • Noise anxiety/storms and fireworks phobias
  • Alopecia (hair loss)
  • Cushing’s disease


Melatonin can be used to treat insomnia in dogs because it helps regulate the circadian rhythm.

Dog’s melatonin production decreases with age, as in humans. It can help older dogs that experience sleeping disorders, making them fall asleep easier and sleep longer.

Melatonin supplements also help regulate the biorhythm of puppies (over 12 weeks) with cognitive dysfunction and make them sleep better.

Anxiety and Phobias

Melatonin has calming effects and can be effective in dogs that suffer from anxiety, including separation and noise anxiety (fireworks and storm phobias).

It can also help dogs relax before a stressful experience, such as going to the vet or before surgery.[5]


Overall, melatonin helps improve coat condition. Pets that suffer from seasonal alopecia (flank alopecia) can be helped by taking melatonin. 

In seasonal alopecia, the dog loses hair on both sides of its abdomen (flank). Breeds more prone to this type of alopecia are Boxer, Bulldog, Airedale terrier, Scottish terrier, Labrador retriever, Akita, and others.[6]

Melatonin can also help if the dog suffers from alopecia-x, which is a non-inflammatory disorder where hair can fall out. The most common dog breeds that are prone to alopecia-x are the Nordic breeds, such as the Chow Chows, Pomeranians, Alaskan Malamutes, and others.

Related: Melatonin for Dog’s Skin

Alopecia in dogs
Image Source

Cushing’s Disease

Cushing’s disease is a medical condition where the adrenal glands overproduce certain hormones, increasing cortisol levels.

Melatonin is gentler than the traditional medication for this disorder. Many veterinarians recommend melatonin for dogs with Cushing’s instead of the usual medication because it has milder side effects.

Melatonin Dosage in Dogs

The melatonin dose for dogs is adjusted according to their weight. Smaller dogs can take up to 1 mg of melatonin, while larger breeds are given 3-6 mg. Never give your dog melatonin before talking to your vet.

Melatonin is given orally in the form of a tablet, capsule, liquid, or gummies, and it takes up to 30 minutes until the effects show. 

There are also implants that release melatonin over time.

Keep in mind that melatonin gummies can have xylitol in their composition. Make sure you check the label before buying melatonin.

Melatonin dosage in dogs for sleep disorders
Dog weightMelatonin dose
< 10 lbs. (~4.5 kg)1 mg
10 – 25 lbs.1.5 mg
26 – 100 lbs.3 mg
> 100 lbs.6 mg

For dogs that suffer from anxiety and phobias the dose is half of that for sleep disorders.

Related: My Dog Ate 10 Mg of Melatonin


Melatonin is a hormone supplement that is safe for dogs. It is used to treat anxiety (including social and noise anxiety), sleep disorders, hyperactivity, alopecia, and Cushing’s disease. You can find melatonin in the form of pills, liquids, gummies, capsules, and implants (veterinary use). Check the label for xylitol.

Do not give your dog melatonin until you talk to your veterinarian. It can have mild adverse reactions. A melatonin overdose can lead to seizures.

The melatonin dosage is calculated according to your dog’s weight. Dogs under 10 lbs. can take 1 mg of melatonin, while those over 100 lbs. can take up to 6 mg.


Can Dogs Have Melatonin?

Yes, dogs can take melatonin orally after you talk to your vet. This supplement is safe for dogs and has few side effects. An overdose can lead to increased heart rate and seizures.

How Much Melatonin Can I Give My Dog?

The dose of melatonin is calculated according to your dog’s weight. Dogs under 10 lbs. can take 1 mg, while those over 100 lbs. can take up to 6 mg of melatonin.

Can Dogs Have Melatonin Gummies?

Yes, dogs can have melatonin gummies if they don’t contain xylitol, which is toxic for dogs. Fruit-flavored melatonin gummies usually contain xylitol. Don’t forget to read the label before purchasing melatonin gummies or other melatonin supplements that are sweet or fruit-flavored.

About Iulia Mihai (DVM)

Dr. Iulia is a certified veterinarian with more than 10 years of experience in the field. With extensive knowledge of diet, care, and medication, she helps Misfit Animals provide readers with accurate knowledge on technical topics.

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