Melatonin in dogs: Everything you need to know about this versatile supplement

Melatonin in dogs
(Image credit: Getty Images)

Have you ever considered the use of melatonin in dogs or found yourself wondering “can you give a dog melatonin?” If so, you’re in good company! Many people turn to melatonin when they need help sleeping, so it’s only natural to wonder if melatonin can offer similar benefits for our pets. Additionally, several canine medical conditions can be treated with melatonin, so your veterinarian may prescribe melatonin for your dog’s treatment, in some cases.

What are the uses for melatonin in dogs?

Melatonin is a hormone that regulates the sleep-wake cycle, mood, and reproduction. While humans often take synthetic melatonin supplements to get more sleep at night or address jet lag, melatonin in dogs has a variety of other uses. 

Like its use in humans, melatonin can be used to address sleep issues in dogs. Many dogs experience disruptions in their sleep-wake cycle as they age, caused by a condition known as canine cognitive dysfunction syndrome. These dogs often have trouble settling down at night and may pace throughout the overnight hours. In these dogs, a dose of melatonin before bedtime can help dogs get a better night’s sleep, which allows the humans in the home to also get a better night’s sleep!

Melatonin is also used to manage a number of skin and coat conditions. In dogs, there are a variety of conditions that cause hair loss and/or poor hair regrowth. Alopecia X, for example, is a poorly understood condition that causes hair loss in several fluffy-coated breeds, such as Pomeranians, Samoyeds, and Chow Chows. The mechanism of Alopecia X is not fully understood, but up to half of diagnosed cases respond to treatment with melatonin. Similarly, canine seasonal flank alopecia (also known as recurrent flank alopecia), pattern baldness, and post-clipping alopecia may also resolve with melatonin therapy. It is not fully understood why melatonin is effective in these conditions, but it is thought that melatonin’s effects on the dog’s circadian rhythm may help promote hair regrowth. 

Melatonin may also be used to treat low platelet counts due to immune-mediated thrombocytopenia. In dogs with immune-mediated thrombocytopenia, the body’s immune system recognizes the dog’s own platelets as foreign. This leads to destruction of the platelets, and lack of platelets causes blood clotting disorders. While the treatment of immune-mediated thrombocytopenia typically requires a combination of drugs, melatonin may be incorporated into some treatment protocols. It is thought that melatonin may play a role in platelet production and regulating the inflammatory response, but melatonin’s role in immune-mediated thrombocytopenia is not fully understood. 

How much melatonin can you give a dog?

The recommended canine dose of melatonin varies, depending on the patient. Doses typically range from 3-6 mg once or twice daily, depending on the dog’s medical condition. Some conditions respond well to low doses of melatonin given once daily, while other conditions require higher doses given twice daily. Additionally, your veterinarian will take your dog’s size into account when recommending an appropriate melatonin dose. 

Human melatonin supplements are safe for use in dogs when used at the correct dosage and for the correct indications. However, it is important to follow your veterinarian’s dosing recommendations. Overdosing may be harmful to your dog, while underdosing your dog may reduce the likelihood of seeing any benefits from treatment. 

Melatonin should not be combined with other prescription or over-the-counter drugs, unless under the guidance of your veterinarian. Melatonin can reduce the efficacy of other drugs, especially blood pressure medications and corticosteroids (such as prednisone). Combining melatonin with anticoagulant medications may increase the risk of bleeding. Therefore, it is important to talk to your veterinarian before treating your dog with melatonin, to minimize the risk of problematic drug interactions. 

Side effects of melatonin in dogs

Melatonin in dogs: Dog at vet

(Image credit: Getty Images)

There has been little research done on the side effects of melatonin in pets. Therefore, much of what we know is based on anecdotal evidence and extrapolated from human side effects. 

Many pet owners have observed that melatonin can cause drowsiness in dogs, much as it does in people. Additionally, melatonin has been observed to inhibit reproduction in breeding pets, affecting both reproductive cycles in females and sperm counts in males.

In humans, melatonin has been associated with several other side effects. Human patients may develop headaches, nausea, dizziness, and transient periods of depression. In human patients with seizure disorders, melatonin may increase the risk of seizures. Less common effects may include autoimmune hepatitis (liver disease), optic nerve abnormalities, skin rashes, and psychosis in humans. It is unknown whether dogs are at risk of these side effects, but it seems reasonable to conclude that they might be. Therefore, melatonin should only be given under the guidance of a veterinarian. 

Can dogs overdose on melatonin?

While melatonin has a relatively wide margin of safety, overdoses can be problematic. If you are concerned that your dog may have ingested an overdose of melatonin, contact your veterinarian’s office. If your veterinarian’s office is closed, contact Pet Poison Helpline or ASPCA Poison Control.

Depending on the dose of melatonin that your dog ingested, your veterinarian may induce vomiting to remove the drug from your dog’s intestinal tract and reduce absorption. Your dog may also require treatment for the vomiting and diarrhea that can occur after an overdose. In severe cases, your dog may need to be hospitalized for intravenous (IV) fluids, monitoring, and more aggressive treatment. 

Conclusion: Can you give a dog melatonin? 

Veterinarians recommend the use of melatonin in dogs for a variety of medical conditions. If your geriatric dog is experiencing altered sleep patterns due to canine cognitive dysfunction, talk to your veterinarian to see if melatonin may be helpful. Additionally, consider talking to your veterinarian about melatonin if your dog has hair loss that is not explained by another underlying skin condition. While the benefits of melatonin can vary, this supplement is associated with few side effects and is a safe treatment option for many dogs. 

Catherine Barnette DVM

Dr. Barnette is a graduate of the University of Florida, where she received both her B.S. in Zoology and her Doctor of Veterinary Medicine (DVM). She has 15 years of clinical experience as a small animal veterinarian, treating dogs, cats, and occasional exotic patients. She now works as a freelance veterinary writer, creating educational content for veterinarians, veterinary team members, and dedicated pet owners. Dr. Barnette lives in southwest Florida with her husband and daughter (plus two cats, a dog, and a rescued dove!) and enjoys kayaking, biking, and hiking. Learn more about Dr. Barnette at