Help! My Dog Ate Melatonin

The Short Answer is:

Dogs are prescribed melatonin by veterinarians. Just as with humans, your veterinarian must give you a prescription in the UK. However, in the US, they can be purchased over the counter, and this is where a lack of control may result in problems for you and your dog.

The purpose of this article is to explain “Help! My Dog Ate Melatonin“.

Melatonin supplements are popular among many of us.

Melatonin supplements are taken by three million adults and half a million children in the United States according to a study in 2018.

Additionally as our ability to sleep decreases over time we will become more dependent on this supplement.

The use of melatonin with our dogs is also possible.

An odd one since very few dogs seems to suffer from sleep problems!

Do certain brands of melatonin have the potential to harm your dog and how is it used with dogs?

This article will attempt to address just two of these questions…

What is melatonin?

Melatonin is a natural hormone that occurs in humans but not in dogs.

This hormone is produced by the pineal gland which is located in the brain.

Melatonin is produced by the gland when it gets dark outside and it continues to produce it until the early morning hours. 

We produce this hormone when we are sleeping and it regulates how we sleep. 

Melatonin pills are also available

At this point you are probably shaking your head and wondering what this has to do with dogs or why are they eating it?

Melatonin is not only a naturally occurring hormone but it is also available as a pill.

While it is available without a prescription and over the counter in the United States it is available only on a prescription from a doctor in the United Kingdom.

Humans are prescribed this medication three times a year for sleep-related conditions. 

1. The treatment of short-term insomnia in adults (over 55 years old).
2. Children who have difficulty sleeping.
3. The treatment of jet lag in adults.

It is also prescribed for some adults with headaches as well as for some adults with vision problems (because the pineal gland cannot produce enough melatonin). 

Can melatonin pills be used with dogs?

Dogs are prescribed melatonin by veterinarians. 

Just as with humans your veterinarian must give you a prescription in the UK.

However in the US they can be purchased over the counter and this is where a lack of control may result in problems for you and your dog.  

There are three main reasons why it is prescribed to dogs:

1. Sleep disturbances in older dogs

2. Elderly dogs often suffer from sleep disturbances

3. Anxiety associated with separation

When it comes to melatonin dogs have an extra-label.

Due to the fact that melatonin pills have not been developed specifically for dogs you must use pills developed for humans or ferrets (yes ferrets!).

What’s the evidence?

Its not surprising that melatonin has been used in limited clinical trials in dogs. 

The most influential person seems to be Dr. Linda Aronson who is a doctor of veterinary medicine (DVM).

In 1999 she published a study in which she used melatonin to calm highly anxious dogs. 

There is no online version of the original article so I have to rely on summaries from other sources. 

More than 80% of dogs who were very afraid of fireworks or thunderstorms were calmed by the drug.

Upon taking the melatonin pill they had a very calm state within 15 minutes. 

What is a safe dosage of melatonin for a dog?

Its not surprising that the dose of melatonin that you should give your dog depends on its size.

You should always follow the advice of your vet. 

The following quantities of melatonin pills are given every eight hours:

• 1.0 mg for small dogs (under 10 pounds) 
• 1.5 mg for medium dogs (between 10 and 25 pounds)
• 3-6 mg for large dogs (between 25 and 100 pounds)

Are there any side effects of melatonin?

Melatonin for dogs is known to be a safe and predictable medication. 

You should not use it on puppies or pregnant fawns however. 

Among the consequences are:

• Unrest in the stomach
• Causing an increase in heart rate
• Accompanied by itchiness and confusion

Can a dog overdose on melatonin?

Wow! Melatonin has been eaten by my dog…

There can be an overdose of melatonin in a dog but it is hard to quantify the amount. 

Scientists do not even know how much melatonin a person needs to overdose so thats one reason for this. 

Although this article estimates that an overdose of melatonin would be three times the recommended dose for a person. 

In regard to the dosage figures mentioned earlier possible harmful levels of melatonin for dogs of three sizes would be:

• The dosage for a small dog (under 10 lbs) is 3 mg 
• Medium dog (10- 25 lbs) 4.5 mg
• Large dog (25- 100 lbs) 9-18 mg

If you suspect your dog has overdosed on melatonin contact your veterinarian immediately or call the Pet Poison Helpline. 

My dog has eaten melatonin with xylitol

In addition to overdosing there is another way that melatonin can endanger your dogs life.

Its when you accidentally give him a human melatonin pill thats sweetened with xylitol.

Xylitol cannot be processed by dogs. 

A dogs blood sugar level will decrease once xylitol enters his/her bloodstream and triggers the release of insulin. 

The liver may eventually fail as a result. 

It is thought that the toxic level of xylitol is around 50 mg per pound of a dogs body weight. (or 100 mg per kg.)

So for my Golden Retrievers who weigh about 60 pounds (30 kg) they would need to consume 3000 mg of xylitol to be in danger which is the equivalent of 3g of xylitol. 

In order to make melatonin pills more palatable xylitol is often added. 

The problem with buying xylitol over the counter is you might accidentally buy a brand that contains xylitol. 

According to Amazon the best-selling brand of melatonin pills (Natrol) contains xylitol.

There is 5mg of melatonin in every pill but it does not state how much xylitol is in each. Xylitol however is the second most popular ingredient in the pills.

Therefore it is really hard to say how many of these pills your dog would have to swallow to be poisoned by xylitol. 

The good news is that the best-selling childrens melatonin “gummies” do not contain xylitol- honey is used as the sweetener instead. 

The symptoms of xylitol poisoning

You should be on the lookout for the following symptoms of xylitol poisoning:

• Vomiting
• Lethargy
• Inability to walk properly (lack of coordination).

It goes without saying that if your dog displays any of these symptoms you need to contact your veterinarian immediately. 

Amanda (Author)

With over a decade of experience, Amanda is a distinguished dog trainer. Her expertise in canine behavior has transformed countless lives, fostering harmonious human-canine connections. Through compassionate and personalized approaches, she empowers owners to understand and connect with their furry companions, creating a legacy of joyful tails and transformed lives.

Osvaldo Maciel (Content Reviewer)

Osvaldo Maciel, a stalwart in the field with 14 years of experience, is a revered dog trainer. His journey is defined by a profound understanding of canine behavior, shaping unbreakable human-canine bonds. Osvaldo guides owners to connect with their beloved pets, leaving an indelible mark of happiness and transformation. His legacy shines through the countless lives he has touched.