Melatonin for Dogs: Is Melatonin Safe for Dogs?

Tossing and turning at night or struggling to fall or stay asleep can be extremely frustrating. It’s not uncommon for humans to take melatonin to help them drift to sleep.

It may have you wondering, “Can my dog have melatonin, too?”

If your dog gets anxious on long car rides, or your puppy doesn’t want to sleep at night, you may have the urge to want to help them catch some sleep. However, you need to understand whether it’s safe to do so.

Read on to learn how melatonin works, if dogs can take this supplement, the potential benefits and risks, and what to do if your dog accidentally ingests too much.

Melatonin is a natural hormone that has many functions, including the regulation of sleep-wake cycles, and many humans use it to aid with insomnia and irregular sleep patterns. But can dogs have melatonin?

“Yep—dogs can use it too,” says Dr. Wayne M. Johnson, veterinarian at Birdneck Animal Hospital in Virginia Beach, Virginia. “It’s actually a pretty common supplement among pet parents.”

Vets will give melatonin to dogs for issues such as:

• Anxiety
• Mild stress or fear
• Sleep disorders, like insomnia
• Canine cognitive dysfunction (dementia)
• Alopecia (hair loss)
• Adrenal diseases, like Cushing’s Disease

The condition you’re targeting will determine how much melatonin your dog needs.

Always speak with your veterinarian about how much melatonin is right for your dog.

Dr. Johnson cautions that moderation is key. “Overdosing on melatonin can lead to drowsiness, an upset stomach, or even more serious issues, like changes in fertility or increased heart rate.”

Work with your vet to determine the proper dosage, based on your dog’s weight and overall health.

According to Dr. Dwight Alleyne, a veterinary consultant with Fido Alert, puppies can have melatonin, but it should be given with extreme caution and for very specific occasions.

“Puppies, due to their developing systems, can be more sensitive to the effects of this supplement,” he explains. “But it’s one of the safer options to use if a puppy is experiencing severe anxiety.”

Dr. Johnson agrees that vets may suggest melatonin for puppies with certain conditions, but the supplement is typically avoided. “The main benefit could be helping with anxiety or sleep, but the risks, like disrupting their growth or causing hormonal imbalances, often outweigh those benefits for puppies,” he says.

The most recognized function of melatonin involves the sleep-wake cycle. The brain naturally starts creating more melatonin as it gets dark out. This helps the body’s internal clock signal that it’s time to go to sleep. Melatonin can also have other effects, including reducing anxiety, stimulating hair growth, and altering the production of other hormones.

Dr. Johnson says that it can help dogs by producing a calming effect and encouraging them to relax. This, in turn, can alleviate anxiety and help them drift off to sleep.

Your dog’s size and the dosage will determine how quickly it kicks in for them. Dr. Johnson says it can start working in 15 to 30 minutes, though Dr. Alleyne notes it can take up to an hour in some dogs.

While melatonin is generally safe for dogs, like most things, it isn’t completely without side effects. Some dogs might experience:

• Mild drowsiness or lethargy
• Vomiting or diarrhea
• Changes in fertility in dogs that haven’t been spayed or neutered

Dr. Johnson cautions that, in rare cases, melatonin could affect a dog’s heart rate or lead to confusion. If you notice any unusual behavior in your dog after giving them melatonin, reach out to your vet right away.

If you know your dog has accidentally ingested too much melatonin, try to stay calm and reach out to your vet or the Pet Poison Helpline® at (855) 764-7661.

“Overdose is rare in dogs, but if a dog has consumed more than double of the recommended dose for melatonin and is showing symptoms, there is a concern for danger,” Dr. Alleyne says.

Symptoms of too much melatonin can include:

• Vomiting
• Diarrhea
• Seizures
• Increased heart rate
• Extreme lethargy

“If your dog seems off or you’re just not sure, it’s always better to be safe and get professional advice quickly,” says Dr. Alleyne.

Do vets recommend melatonin for dogs?

Melatonin is a commonly recommended supplement for dogs suffering from anxiety, sleep disorders, or hair loss. It is typically not recommended for puppies because of potential side effects on their developing bodies.

Always talk with your veterinarian before giving melatonin or any other supplement, to make sure they are the right fit for your dog.

What happens if my dog eats five milligrams of melatonin?

Melatonin is a commonly used supplement for dogs, and five milligrams is safe for most. Small dogs, however, may experience stronger side effects like drowsiness due to their size. If you’re ever concerned, call your vet or the Pet Poison Helpline® at (855) 764-7661 for guidance.

Will 10 milligrams of melatonin hurt my dog?

Ten milligrams is higher than most recommended dosages for dogs.

Your dog may be lethargic or have GI upset if they are given this amount, especially smaller dogs. If you notice any symptoms, or your dog is acting a bit off, it’s better to be safe and call your vet.

This content was medically reviewed by Chewy vets.