Melatonin for Dogs: Dosage and Side Effects in [2021]

Do you want to help your anxious dog but would prefer to avoid using drugs?
One option you may want to explore is melatonin for dogs.

Melatonin For Dogs

What is Melatonin?

Melatonin is a hormone that occurs naturally in the body and is made by the pineal gland in the brain.
Melatonin is produced in cycles during the day with the peak occurring at night.

For this reason in people it is often referred to as the ‘sleep hormone’ because more is produced when we sleep…or could it be that we sleep better with a lot of melatonin in our bloodstream?

Some people take melatonin to help regulate their sleep when they suffer from jet lag or have irregular sleeping patterns because of shift work.

Indeed, some blind people take melatonin to establish a day: night pattern and improve their sleep.

Melatonin in Dogs

In animals it’s thought that melatonin plays an important role in regulating functions such as sleep patterns, hair growth, is beneficial to their reproductive cycles.

white dog smiles on dogstruggles

Can dogs take Melatonin?

Yes. Because melatonin is a substance that occurs naturally in the body, it is considered a supplement rather than a drug.

Whilst the beneficial effects of giving melatonin have not been proven, many dog owners anecdotally report that it has made a difference to dogs with problems such as anxiety, poor sleep, reduced appetite, or hair growth problems.

The counter argument by scientists would be that many of the improvements seen when a melatonin supplement is started are largely coincidental.

For example, when melatonin is given to improve hair regrowth in a dog with a poor coat, doubters argue that seasonal changes were responsible for the improved quality of the fur rather than the supplement.

Can I Give My Dog Melatonin?

Yes, but anyone considering giving their dog a melatonin supplement should keep in mind that they do so in the knowledge that it is ‘experimental’ at best and there is no guarantee of achieving a beneficial effect (and indeed any improvements may just be coincidental.)

If you decide that melatonin is worth a try (after all what does it matter why the dog improves, as long as he feels better) then it helps to know which conditions it’s most likely to help.

Can Melatonin Help?

Although people largely take melatonin for sleep-related disorders, in dogs it is used for a wider variety of reasons.

The commonest indications for melatonin in dogs are to help separation anxiety or phobias and to promote hair growth.

To answer the question: “Does melatonin work in dogs?” let’s take a look at some of the indications for taking it in more detail.


Dogs can suffer from anxiety for all sorts of reasons.

It might be the dog is a rescue and was poorly socialized early in life, leaving him a bag of nerves in novel situations.

Other dogs can be over-attached to their pet parent and suffer the doggy equivalent of a panic attack when left alone.

Whatever the reason, anxiety-related disorders are extremely common in dogs and the distress caused to both pet and pet parent should not be underestimated.

Key to tackling anxiety in the long term is identifying the cause and retraining the dog, but often it’s necessary to ease the dog’s distress in the short term.

This is where melatonin can come in.

Some people find it beneficial to give to their dog in order to ease anxiety, whilst other report it can help against anxiety-related phobias such as noise aversion to loud fireworks.

Alopecia X

Alopecia is another way of saying “Hair loss” and Alopecia X goes by a variety of names.

These include as sex-hormone related alopecia, adult onset hormone related hair loss, and pseudo Cushing’s disease.

These names all reflect the fact that researchers have little idea of the true cause behind the general loss of hair over the trunk of breeds such as the Pomeranian.

For a while, it looked like melatonin was the answer to help hair regrowth since dogs on this supplement grew a plush coat of fur.

However, sceptics now say this is most likely to be a coincidence and that the dog had reached a point in the hair growth cycle where it was going to come back anyway.

Whichever viewpoint you take, if you have a bald Pomeranian and a treatment that is relatively side-effect free is available over the counter, then that option is worth considering.


One of the side effects of melatonin is that it stimulates the appetite, which can be a boon if you have a dog that’s a poor eater and you want to encourage him to gain weight.


In the same way that anxiety has an underlying cause, poor sleep patterns can be due to pain (such as the discomfort of nagging arthritis, toothache, or an ear infection).

Be sure to eliminate any such causes, but if the problem seems to be entirely emotional then some owners find giving melatonin can be beneficial to help their dog get a good night’s sleep.

dogs together sleeping

Melatonin Side Effects in Dogs

Everything you’ve read so far has you thinking that melatonin might be worth a try in your dog.

Quite naturally you want to know: “Is melatonin safe for dogs?”

The short answer is, yes, it is relatively safe and has few side effects.

When given at the recommended dose the side effects (if they occur) are usually mild and wear off as the levels ebb in the bloodstream.

The commonest side effects include:

  • Sleepiness
  • Sedation and/or confusion
  • Stomach ache
  • Sickness and/or diarrhea
  • A rapid heart rate

However, when giving your pet any supplement or medication it’s always best to check with your vet first that it’s suitable in your dog’s individual case.

Also, keep in mind that having a vet check and reaching a diagnosis as to the underlying nature of the problem, is the best way to get the issue sorted out.

There is little point in making a painful dog sleep through the night with melatonin when what he needs is a rotten tooth extracted.

yellow to brown puppy sleep

This is especially true in cases of hair loss where conditions such as hypothyroidism (underactive thyroid glands), Cushing’s disease, and skin infections need to be ruled out.


There has been little formal investigation into the action on melatonin in dogs, and so information is limited and is largely extrapolated from humans.

With this in mind, it’s best to play it safe and not give melatonin to pregnant dogs or to puppies.

Also, since melatonin is contraindicated in people with liver or disease, or with blood clotting issues, it is wise to avoid giving melatonin to dogs with these conditions.

Melatonin is also thought to interfere with blood clotting mechanisms, and so should not be given with drugs such as aspirin or NSAIDs (non-steroidal anti-inflammatory drugs).

Again, check with your vet is in doubt.

As to dosage, melatonin is available as an oral tablet or an injectable implant.

Dog melatonin overdose is theoretically possible but rarely happens.

If the dog eats excessive amounts, such as he gets access to the bottle of tablets and eats them all, then contact your vet for emergency treatment.

Injectable Implant: Dermatonin is an injectable implant administered under the skin of your dog’s shoulder by the vet.

It works for around four months and is best suited for the management of Alopecia X.

The idea is to provide a constant, slow-release depot of melatonin in order to stimulate hair regrowth.

smiling dog on dogstruggles

Oral Tablets

The melatonin for dogs dosage for the oral supplement is 3 – 6 mg per dog given two or three times daily.

The oral form is widely available without prescription from pharmacies and health food stores.

Bottom Line

Yes, you can give dogs melatonin but you do so on the understanding that it’s not guaranteed to make a difference, but on the other paw what do you have to lose? Read our comprehensive guide on Dog Medication here. 

Dr Sarah Robinson attended veterinary school at Oklahoma State University receiving a D.V.M. in 2008. Sarah’s longtime interest is to help people to better communicate with their pet companions, and in doing so, to help them to strengthen their relationships with their dogs and cats. Sarah has published numerous articles on canine feeding in pet related magazines, veterinary journals and leading natural health web sites.

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