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My Dog Ate 10 Mg Melatonin: Should You Worry? (What to Do)

10 Mg of melatonin usually doesn’t affect a large dog but can have a significant effect on smaller dogs. The therapeutic dose is 1 mg/10 lbs. of body weight, meaning smaller dogs can overdose on 10 mg of melatonin. Contact your veterinarian if your dog shows symptoms of a melatonin overdose.

Melatonin is a natural hormone secreted by the pineal gland of mammals, including humans and dogs. This secretion helps regulate sleep-wake cycles, sending messages when it’s time for the body to relax and prepare for rest.

For dogs, melatonin is used as a sleeping pill and helps them fight separation anxiety or get over storms or noisy events. Melatonin is also used in the form of melatonin implants for recurring hair loss.

Even though melatonin has all these benefits for dogs, it has to be recommended by your veterinarian. 

It is never a good idea to give your pet supplements without understanding what you are giving it.

In this article, you will find out what happens if your dog eats 10 mg of melatonin, if melatonin is safe for dogs, how much melatonin is lethal for a dog, and much more.

Don’t forget to consult your veterinarian before you give melatonin to your dog.

Is Melatonin Safe for Dogs?

Melatonin is considered safe for dogs as long as it has been recommended by your veterinarian. It can have rare side effects if the recommended dose is exceeded. It poses a risk to young puppies and pregnant and lactating females.

According to ASPCA (American Society for the Prevention of Cruelty to Animals), melatonin is considered safe for dogs[1], and side effects are usually rare and minor.

Melatonin is prescribed by veterinarians for dogs for the following medical conditions:

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

The recommended dose of melatonin for dogs can be seen in the chart below.

Dog’s WeightMelatonin dose (mg)
< 20 lbs. (~10 kg)1 mg
10 – 25 lbs.1.5 mg
26 – 100 lbs.3 mg
> 100 lbs.6 mg

Melatonin is not recommended for:

  • Puppies under 12 weeks
  • Pregnant and lactating females[2]
  • Dogs that have problems with their liver, kidneys, or brain
  • Dogs that are treated with anticoagulants [3]

It is generally safe for dogs even at higher doses, but should not contain xylitol. Xylitol is an artificial sweetener found in most melatonin gummies. 

Xylitol is poisonous to dogs and cause the following symptoms:

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

Symptoms of xylitol poisoning begin 30 minutes after ingestion and last up to 12 hours.[4]

What Happens if a Dog Eats Melatonin?

The effect of melatonin on dogs depends on the ingested amount. A dog will be sleepy if it consumes a recommended dose of melatonin, experience mild digestive problems when ingesting slightly larger amounts than the recommended dose, or overdose when consuming too much melatonin.

If your dog eats melatonin, check how much melatonin it has consumed and whether or not the product contains xylitol.

Pure melatonin is unlikely to cause your dog’s death no matter how much it eats. But there is still a risk.

The symptoms of a melatonin overdose differ depending on your dog’s weight and the amount of melatonin ingested.

Related: Can Melatonin Kill Dogs?

What Happens if a Dog Eats Melatonin
Milligrams of melatoninPotential side effects in adult dogs*
1 mg of melatoninNo sign of overdose if it weighs up to 10 lbs. Otherwise, it can be drowsy.
5 mg of melatoninDrowsiness and stomach upset, depending on its weight and the amount ingested compared to the recommended dose.**
10 mg of melatoninVomiting, lethargy, and sleepiness. Itching and an elevated heart rate can occur in small breed dogs.
20 mg of melatoninIncoordination, high blood pressure, and seizures.
30 mg of melatoninIncoordination, high blood pressure, and seizures.

*Pregnant or lactating females are not taken into account.

**The recommended dose of melatonin is 1 mg/10 lbs. body weight.

How Much Melatonin Is Lethal for a Dog?

There is no studied lethal dose of melatonin for dogs. Melatonin is rarely fatal for dogs, but it can cause severe symptoms that require immediate veterinary care.

A large overdose of melatonin is unlikely to lead to death in dogs.[5] Studies have shown that dogs can ingest doses of up to 80 mg of melatonin per lb. body weight and survive.[6]

If your dog eats melatonin gummies containing xylitol, it can lead to severe symptoms, including death.

How Much Melatonin Is Lethal for a Dog

What Are the Signs of a Melatonin Overdose in Dogs?

Most dogs are lethargic and disoriented after consuming higher amounts of melatonin. In other, more severe cases, ingestion of melatonin can lead to increased heart rate, panting, gastrointestinal upset, and seizures.

Symptoms of melatonin overdose usually occur within 20 to 30 minutes of ingestion. 

Depending on the amount of melatonin ingested, symptoms of overdose include:

  • Gastrointestinal problems: upset stomach, vomiting, and/or diarrhea
  • Drowsiness
  • Lethargy
  • Itchiness
  • Incoordination (wobbly walk)
  • High blood pressure
  • Fast heart rate
  • Seizures

What Happens if a Dog Eats a Whole Bottle of Melatonin?

As melatonin is not fatal to dogs, even in high doses, the effects of overdose should wear off in 12-24 hours, depending on how much melatonin your dog ate.

Talk to your veterinarian if you suspect your dog has eaten melatonin.

What to Do if Your Dog Eats Melatonin

Go to the vet immediately if your dog has eaten melatonin and you notice one or more of the symptoms of an overdose. In case of a mild overdose, let your dog sit calmly in a dark and quiet room to recover.

The first thing to do if your dog eats melatonin is to estimate how many melatonin tablets your dog has consumed. Then check the dose on the package to calculate the corresponding milligrams of melatonin.

Melatonin supplements for human consumption are similar to those for veterinary use. They don’t cause side effects if they don’t contain xylitol and are administered at the recommended dose.

Contact your vet immediately for medical attention if you suspect or calculate that your dog has eaten a high amount of melatonin tablets or gummies.

If the amount ingested is very high, your veterinarian can suggest inducing vomiting to remove the ingested tablets. This is recommended when the amount of ingested melatonin is considered dangerous to be digested.

Do not induce vomiting unless instructed by a veterinarian, regardless of the medicine or substance your dog has ingested.

See a veterinarian immediately if the amount of melatonin ingested is acceptable, but the product contains xylitol.

Uses of Melatonin for Dogs

Your veterinarian can recommend melatonin for your dog to treat various medical conditions such as alopecia or behavioral and sleep disorders. Do not use melatonin without a prescription for your dog, as it can cause side effects or interact with other negative medicines.

Melatonin is recommended by your veterinarian to treat the following medical conditions:

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


Insomnia on dog

Melatonin can be used for insomnia in dogs because it regulates the circadian rhythm (sleep-wake cycle).

The production of melatonin in a dog’s brain decreases with age, as it does in humans, resulting in difficulty sleeping. Melatonin can help older dogs fall asleep faster and get a better night’s sleep.

Melatonin supplements are also used to help puppies over 12 weeks sleep better.

Anxiety and Phobias

Due to the calming effects of melatonin, it is effective for dogs suffering from fireworks and storm phobias, anxiety caused by cognitive dysfunction (old dogs)[7], and separation anxiety.

Melatonin can also help dogs that are going through stressful and unpleasant experiences, such as going to the vet. It is used before surgery to calm your dog.[8]

Alopecia X

Melatonin for Seasonal Alopecia
Image Source

Dogs with Alopecia X experience hair loss due to non-inflammatory causes. The most predisposed breeds to Alopecia X are Chow Chows, Pomeranians, and Alaskan Malamutes.

In this case, melatonin is recommended as it helps improve coat conditions in dogs.

Cushing’s Disease

Cushing’s diseases affect the adrenal glands of dogs, resulting in the overproduction of certain hormones and increased cortisol levels. Melatonin is recommended by veterinarians because it has fewer side effects than classic treatment.


Will a Melatonin Gummy Hurt a Dog?

Melatonin gummies can hurt dogs, especially if they contain xylitol. Melatonin alone can have rare and mild side effects, unlike xylitol which leads to poisoning and death. Symptoms of xylitol poisoning in dogs include vomiting, dizziness, incoordination, seizures, and collapse.

Can dogs overdose on melatonin?

Melatonin overdose in dogs can happen in rare cases if the dose consumed is extraordinarily high. Symptoms of melatonin overdose include vomiting, diarrhea, nausea, increased heart rate, itching, and seizures. Death can occur in exceptional cases.

Can Dogs Have Melatonin?

Yes, dogs can take melatonin orally for various medical conditions, including insomnia, anxiety, and noise phobias. Never give your dog melatonin unless instructed by your vet, as it can lead to gastrointestinal problems and can interact with other medications. If your dog suffers from renal or hepatic conditions, it should not take melatonin.

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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