What Should You Do If Your Dog Ate Melatonin?

Melatonin is a hormone that is already present in our bodies, both in humans and dogs. It can also be taken as a supplement and it comes in tablets, gummies, and liquids.

If your dog eats melatonin, check how much melatonin they actually ate.

A high dosage or amount of melatonin ingested will be harmful to your pet, especially if it contains xylitol. Otherwise, melatonin is mostly harmless for dogs.

What Should You Do If Your Dog Eats Melatonin?

Try to make an estimate of how many tablets of melatonin your dog ate and check the dosage on the bottle to calculate how many mg they ingested.

Melatonin products for humans are very similar to those for dogs and aren’t toxic if given in the right dosage.

For dogs, this dosage should be 1 mg per 10 pounds of weight up to three times a day or in any case not over 30 mg per day (mind that the latter dosage usually only applies to very large dogs).

If you suspect your dog may have eaten more than that, contact your veterinarian or the Pet Poison Helpline to know how to proceed.

They may suggest you induce vomiting in your dog to get the tablets out if the amount is deemed too dangerous to be digested.

If your dog ate melatonin pills and you find xylitol among the ingredients, rush your dog to the veterinarian because they could be at risk of severe low blood sugar.

Uses Of Melatonin In Dogs

Melatonin is actually used as a therapy for dogs as well as humans and there are many melatonin-related products on the market targeted specifically for dogs, including melatonin treats.

Melatonin in dogs is used as a sedative that helps the neurohormone produced by the pineal glands.

As with every change in your dog’s diet and therapy, you should never start this new supplement without consulting your veterinarian first.

The use of melatonin has proved useful in alleviating several conditions that often affect dogs, like separation anxiety and insomnia.

Given in the right dosage, this hormone is completely safe and can only bring benefits for your dog.


Many dogs are anxious by nature or breed, and many others suffer from separation anxiety because they’re forced to spend many hours a day alone at home while their owners are at work.

Melatonin could also help dogs face difficult situations such as fireworks, thunderstorms, periodic medical examinations, a visit to the groomer, or a long car ride.

Be mindful that melatonin is not a cure for anxiety because it doesn’t work on the part of the brain that manages stress and anxiety, so if your dog suffers from severe anxiety, it would be better to discuss your options with your vet.

This supplement is also helpful in treating hyperactive dogs or dogs affected by epilepsy.


Our health starts with our sleep pattern and melatonin helps regulate our internal clock, the one that tells our bodies whether it’s time to sleep or to be awake.

Puppies often have trouble sleeping at night, mainly because they sleep a lot during the day, but it is usually just a phase they grow out of when they become adults.

However, as melatonin is a hormone produced by our bodies at night, as the seasons change and daylight time with it, the levels of melatonin in your dog’s body change too.

Sometimes, this can lead even adult dogs to develop insomnia or problems sleeping more than a few consecutive hours.

Old dogs that are starting to develop cognitive dysfunctions may have problems regulating their internal clock.

In this case, melatonin is really beneficial for their biorhythms and helps them sleep peacefully at night.


Dogs that suffer from hair loss sometimes find benefits in a melatonin treatment.

The role of melatonin in restoring a dog’s hair is not scientifically proven and remains largely a mystery, but since the downside is riskless it may be worth a try.

There are two types of Alopecia:

  • Seasonal Flank Alopecia: As the name says, this kind of Alopecia comes and goes with seasons;
  • Alopecia X: It is basically the same as seasonal alopecia, except this condition may affect your dog all year-round.

Alopecia in dogs provokes one or more hairless patches on either side of the body and can be an eyesore, on top of being uncomfortable for your dog.

Sometimes a dog’s hair grows back once they’ve been neutered. However, if this isn’t the choice you want to make for your pooch, melatonin is definitely something you could try.

Cushing’s disease

Cushing’s disease happens when a dog has an overproduction of the cortisol hormone.

Cortisol is useful to the body because it helps to manage stress and modulates the immune system, but too much cortisol in the body can be harmful.

Cushing’s disease is usually a consequence of benign pituitary tumors, therefore it is treated with heavy medications that can sometimes cause harsh side-effects like diarrhea and vomiting, going as far as kidney failure.

This is why for mild cases of Cushing’s disease, melatonin is preferred because it is a natural method to help the body blocking the absorption of high levels of cortisol.

Will Melatonin Hurt a Dog?

Melatonin given in the right dose for your dog’s weight and size will not hurt him. It is actually recommended by some veterinarians for natural treatments of various conditions.

If you have human melatonin at home and your dog happens to eat some, depending on the dose your dog may experience side effects.

A dog that ate 10 mg melatonin, even if just a few tablets, will be more likely to get sick than a dog that ate the same amount of tablets but in 1 mg doses.

Luckily, however, melatonin is mostly innocuous alone.

Nonetheless, it would be better to give your dog melatonin products designed for pets, rather than human melatonin, because you will gain peace of mind about side effects and you will also avoid nasty ingredients like xylitol.


Xylitol is an industrial sweetener that is used as a substitute for sugar in many products and foods today.

It is meant for human consumption and it’s particularly appreciated by people who don’t want to give up on something sweet during a diet.

This sweetener is unfortunately extremely dangerous for dogs because it takes a very little amount of xylitol to cause hypoglycemia in dogs.

Hypoglycemia, or low blood sugar, happens when the levels of glucose in the blood are too low for the body to function properly.

It’s a medical emergency because when the glucose level drops too low it can be fatal.

Symptoms of hypoglycemia include:

  • Tremors
  • Weakness
  • Lack of coordination
  • Inability to walk or move
  • Seizures
  • Collapse

These symptoms begin around 30 minutes after your dog ingested xylitol and can last up to 12 hours.

Sometimes xylitol is slowly absorbed by the body, so symptoms do not actually show up before 12 hours in, and then quickly escalate to seizures and collapse. This is why dogs who ingested large quantities of xylitol are usually hospitalized for at least 24 hours.

Another risk related to xylitol is hepatic necrosis, which means that liver tissue gets destroyed by this chemical compound within 8-12 hours from ingestion.

It’s important to notice that not all dogs who experience hepatic necrosis have an episode of hypoglycemia prior to that.

It is unclear how xylitol manages to cause hepatic necrosis, but it usually takes a large amount of xylitol for that to happen, and sometimes it leads to internal hemorrhage, liver failure, and death shortly after.

The higher the dosage the higher the risk of complications. For example, if your dog ate a bottle of melatonin that contains xylitol, you should bring them to the vet immediately.

What Happens If a Dog Eats Melatonin?

Melatonin is safe for dogs if you follow your veterinarian’s therapy and make sure they don’t have access to the supplement on their own.

Even when accidental ingestion happens, melatonin in itself isn’t particularly harmful to dogs and certainly, it would take quite a good amount of it for any kind of adverse reaction to show up.

So if your dog ate a melatonin gummy, watch them go on their merry way with no problems.

Side Effects Of Melatonin In Dogs

When your dog has had too much melatonin or when your dog’s organism doesn’t agree with melatonin, they may experience a variety of symptoms, which is why it’s important not to administer melatonin to dogs without your veterinarian’s approval.

These are common side-effects of melatonin in dogs:

  • Drowsiness: the most common side-effect of mild melatonin intoxication is sleepiness. Your dog may feel lethargic or just a little lazier than usual. They may be uninterested in playing or other usual activities.
  • Upset stomach: Another very common side-effect for mild intoxication. It isn’t usually very concerning, but you can help your dog by withholding food for a few hours, providing them with lots of water, and feeding them with foods rich in fibers like mashed potatoes, white bread, and canned pumpkin.
  • Insulin resistance: Sometimes (rarely) overdose of melatonin can cause insulin resistance in diabetic dogs. This means the body is unable to absorb the insulin as well as before and they may need more units to metabolize the same amount of food.
  • Increased heart rate: Melatonin can cause increased heart rate in old dogs, dogs with pre-existing conditions, or simply dogs that are predisposed or more sensible to it.
  • Allergies: This is an unpredictable side-effect, but as with any other medication, food, or product, it may happen that your dog is simply allergic to melatonin. You may notice symptoms such as vomiting, diarrhea, or unusual behavior and you should bring your dog to the vet as soon as possible.
  • Other medications: Before giving your dog melatonin, remember to consult with your veterinarian to make sure the supplement doesn’t interfere with other medications your dog is taking. Mixing different medications is never a good idea because the outcome could be very harmful or even fatal for your dog.

Can Dogs Eat Melatonin?

Melatonin is deemed safe for dogs and treatments with this supplement are sometimes encouraged for the benefits they could bring to dogs with conditions such as anxiety, alopecia, and insomnia.

Before administering melatonin to your dog, always consult your veterinarian to make sure it is the right treatment for your pooch and to establish the right dose for them.

An excess of melatonin in a healthy dog is usually harmless, however, in the presence of other medical conditions and treatments, it could be harmful.

If your dog ate melatonin that contains xylitol, it is a medical emergency that requires immediate treatment and hospitalization.

Since xylitol is usually present in melatonin products for humans, make sure your dog doesn’t have access to your melatonin bottles by storing them away from your pet.

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