Transparency Disclosure — We may receive a referral fee for products purchased through the links on our site…Read More.

Should I Give My Dog Melatonin?

Did you know that melatonin is synthesized in every living organism1, including bacteria, yeasts, fungi, animals, and plants? 

Melatonin is naturally produced. Its initial function was to detoxify free radicals, and these days in animals, melatonin helps regulate sleep, circadian rhythms, and the immune system, as well as reduce oxidative stress.1

This means that, just like you, your dog produces melatonin2 each night as it gets dark. This helps your dog to not only get sleepy, but behind the scenes, it helps their cognition, among other things.2 

This also means that your dog may benefit from a boost in their melatonin levels via supplements. In this article, we’ll discuss the safety, efficacy, dosage, and possible side effects of melatonin supplements for dogs. 

Is Melatonin Safe for Dogs?

As mentioned, melatonin is a hormone that your dog already naturally produces. According to the American Society for the Prevention of Cruelty to Animals (ASPCA), melatonin supplements are generally considered “very safe for dogs3” and could be used to treat certain issues. 

That said, you should be very careful about giving your dog human melatonin supplements, as they might contain ingredients aside from melatonin that could be dangerous for dogs. For example, human melatonin gummies, tablets, or liquids may contain xylitol, an artificial sweetener. Xylitol is extremely toxic for dogs.3 

Some human melatonin supplements have also been found to contain ingredients not listed on the label4, including doses of melatonin that far outweigh what is listed, as well as serotonin. If you inadvertently give your dog too much serotonin, it could be fatal5

So to be safe, always consult your vet before giving your dog any new supplements or medications. 

Is Melatonin Effective for Dogs?

According to Linda Aronson, DVM6, melatonin has about an 80 percent success rate in her canine patients. Aronson adds that, unlike humans who take melatonin, most dogs won’t sleep after taking it.

What Does Melatonin Help Treat in Dogs?

  • Separation anxiety If your dog exhibits extreme stress whenever you two are apart, they may have separation anxiety7. According to the American Kennel Club8 (AKC),  melatonin can be an effective treatment for separation anxiety in dogs. 
  • Noise phobias – Melatonin has been shown to be particularly effective in treating noise phobias in dogs, such as fireworks, thunderstorms, gunshots, planes, road noises, and more.6 
  • Canine alopecia Canine alopecia9 is when your dog’s hair sheds abnormally, resulting in bald spots and thinning fur, and it may come with itching or scratching. Alopecia can be caused by different factors, but according to the AKC, melatonin supplements may help.8  
  • Cognitive dysfunction – Older dogs can get what we think of as Alzheimer’s, though in dogs it is called “Cognitive Dysfunction Syndrome10.” Just like supplemental melatonin is being studied11 to help treat Alzheimer’s in humans, according to the AKC, melatonin can also help treat cognitive dysfunction syndrome in dogs.8 
  • Circadian rhythm regulation in blind dogs – Being able to sense whether it is dark or light outside plays a vital role in regulating our circadian rhythms and melatonin production11. So, when a person is blind and can’t sense darkness, it may impact their body’s ability to produce melatonin at the right time of day to get sleepy at night. In these cases, supplemental melatonin may help. According to the AKC, this is true for dogs, as well.8 
  • Cancer treatment – Melatonin has also been shown to help dogs going through chemotherapy12 feel better, eat better, and gain weight.
  • Reducing propofol during surgery – Melatonin has been shown to help calm dogs down before surgery13. In the study, dogs who were given melatonin before surgery needed less of the anesthetic propofol during surgery. This is important because propofol may cause respiratory depression and apnea14 (breathing pauses).
A dog is resting on the edge of Leesa bed

What Is the Melatonin Dosage for Dogs?

Over her years of treating canine patients with melatonin, Dr. Aronson came up with some rough guidelines for dosage, depending on the dog’s weight. Dr. Aronson also advises that these doses should be given solely in tablet form – not sublingually (under the tongue), as capsules, or as time-release formulas.7

  • Less than 10 pounds: up to 1 milligram
  • 10 – 25 pounds: up to 1.5 milligrams
  • 25 – 100 pounds: up to 3 milligrams 
  • Over 100 pounds: up to 6 milligrams

Some experts suggest that you can give your dog melatonin every six to eight hours15, while others recommend one dose per 24 hours16. The dosage and frequency can vary, depending on why you are giving your dog melatonin in the first place

This is why it’s so important to speak to your vet before introducing melatonin supplements to your dog. Your vet may have specific recommendations on brand, dosage, and timing, or they may advise against taking melatonin. The point is that they know your dog’s health history and can make the best recommendation possible. 

When Should I Give My Dog Melatonin?

Melatonin should work within one or two hours after administration in dogs.16 This means that if you’re giving your dog melatonin for anxiety or phobias, it will be best to give it to them about one or two hours ahead of the “triggering event”. Likewise, if you’re giving your dog melatonin to help with sleep at night, give it to them one or two hours before bedtime. 

If you’re giving your dog melatonin to help with a more ongoing issue like alopecia, cognitive dysfunction syndrome, or cancer/chemotherapy, the timing of the dose matters less since it is more about melatonin’s other properties like reducing oxidative stress17.

If you and your vet have agreed that melatonin should be taken prior to your dog’s surgery, research shows that giving it 90 minutes before should be most helpful.13 Only give your dog melatonin before surgery with your vet’s knowledge and approval. 

Melatonin for Dogs: Possible Side Effects

Side effects of melatonin are rare in dogs, but may include the following8, 16

  • Fertility changes
  • Upset stomach and stomach cramps
  • Increased heart rate
  • Itching
  • Confusion
  • Sleepiness

How to Choose a Melatonin Supplement for Your Dog

You can either give your dog melatonin supplements or chews that are designed for dogs, or you can give them human melatonin. In either case, melatonin is not regulated by the FDA so you’ll want to be careful when picking your product. Follow these steps to ensure you’re picking the safest product for your dog. 

  1. Speak to your vet – Before buying any melatonin product for your dog, speak to your vet to make sure melatonin is the right choice for them in the first place. If it is, your vet will likely have some specific recommendations for products and dosage. 
  1. Look for “USP-verified” – Since melatonin is not regulated by the FDA, there is no guarantee that all products will actually include what they say on the label.4 However, products marked “USP-verified18” have been third-party-tested to ensure that the ingredients and dosage match what is on the label.  
  1. Look out for toxic ingredients – Some human melatonin supplements contain the artificial sweetener Xylitol, and others may contain 5-HTP or other forms of serotonin.3, 4 These ingredients are extremely toxic to dogs.3, 5 If you have any concerns about the ingredients in a melatonin product, be sure to run them by your vet. 
  1. Consider the form of melatonin – Does your dog hate taking pills? Is he or she a master at spitting them out? In cases like these, chews or liquid formulations may be preferred. 
  1. Consider your dog’s allergies – Melatonin dog chews may contain ingredients like wheat, soy, or poultry. For many dogs, this will be fine, but for some dogs, ingredients like these can cause itchiness and stomach upset19. If your dog has any food allergies, make sure these ingredients aren’t listed on the label. 

Frequently Asked Questions

What if I give my dog too much melatonin?

Luckily, accidentally giving your dog slightly too much melatonin is unlikely to cause harm. The most common side effects include upset stomach or excessive sleepiness, and they should naturally wear off.16 

If your dog consumes an entire bottle of melatonin, though, side effects might include itchiness, dizziness, high blood pressure, rapid heart rate, and in some dogs, seizures.16 In the event your dog does consume an excessive amount of melatonin, though, it is best to be safe and contact your vet, ASPCA poison control, or a veterinary emergency center. 

How do dogs respond to melatonin?

Melatonin typically has a calming effect on dogs. If given at night, it may make them sleepy.8 

How long does it take melatonin to kick in for a dog?

Melatonin should start working within one or two hours of administration.16

Natalie Grigson

Natalie Grigson


About Author

Natalie is a content writer for Sleep Advisor with a deep passion for all things health and a fascination with the mysterious activity that is sleep. Outside of writing about sleep, she is a bestselling author, improviser, and creative writing teacher based out of Austin.

Side Sleeper


  1. Zhao, Dake., et al. “Melatonin Synthesis and Function: Evolutionary History in Animals and Plants”. Frontiers in Endocrinology. 2019. 
  2. Bódizs, Róbert., et al. “Sleep in the dog: comparative, behavioral and translational relevance”. Current Opinion in Behavioral Sciences. 2020. 
  3. “Rest Easy: Getting the Facts on Pet Safety and Sleep Aids”. ASPCA. 2019. 
  4. Erland, Lauren A.E., Saxena, Praveen K. “Melatonin Natural Health Products and Supplements: Presence of Serotonin and Significant Variability of Melatonin Content”. Journal of Clinical Sleep Medicine. 2017. 
  5. “5-Hydroxytryptophan”. American College of Veterinary Pharmacists. Webpage accessed January 9, 2024. 
  6. “Melatonin for stress”. Webpage accessed January 9, 2024. 
  7. Gibeault, Stephanie. “Separation Anxiety in Dogs: Causes, Prevention, and How to Solve It”. American Kennel Club. Last modified September 25, 2023. 
  8. Reisen, Jay. “Melatonin for Dogs: Uses, Benefits and Dosage”. American Kennel Club. Last modified October 2, 2023. 
  9. Gewirtz, Elaine Waldorf. “Alopecia in Dogs: Why Is My Dog Losing Hair?”. American Kennel Club. Last modified June 17, 2022. 
  10. Reisen,  Jay. “Can Senior Dogs Get Alzheimer’s?”. American Kennel Club. Last modified August 2, 2022. 
  11. Roy, Jaydeep., et al. “Role of melatonin in Alzheimer’s disease: From preclinical studies to novel melatonin-based therapies”. ScienceDirect. 2022.  
  12. Dressler DVM, Demian. “More Melatonin and Dog Cancer”. Dog Cancer Blog. Last modified April 13, 2021.
  13. Niggemann, Johanna R., et al. “Preoperative calming effect of melatonin and its influence on propofol dose for anesthesia induction in healthy dogs”. National Library of Medicine. 2019. 
  14. Cattai, Andrea., et al. “Haemodynamic changes during propofol induction in dogs: new findings and approach of monitoring”. BMC Veterinary Research. 2018.
  15. Shipstone, Michael. “Hormonal Treatment for Integumentary Disease in Animals”. MERCK Veterinary Manual. Last modified November 2022. 
  16. Stregowski, Jenna. “Can Dogs Have Melatonin?”. DailyPaws. Last modified June 23, 2022. 
  17. Sharifi-Rad, Mehdi., et al. “Lifestyle, Oxidative Stress, and Antioxidants: Back and Forth in the Pathophysiology of Chronic Diseases”. Frontiers in Psychology. 2020. 
  18. “USP Verified Mark”. Webpage accessed January 10, 2024. 
  19. Weir DVM, Malcolm., Barnette DVM, Catherine., Ward, DVM, Ernest. “Allergies in Dogs”. VCA Animal Hospitals. Webpage accessed January 10, 2024.