Should I Give My Dog Melatonin?

Written by Natalie Grigson, Writer

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In This Article

Discover the safety and effectiveness of melatonin for dogs, explore potential side effects, and learn how to make the right choice for your furry companion.

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

Scientists believe that melatonin has been present in all species that have ever existed on this planet. They say 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 immune system and cognition, among other things.^2,3 

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. 

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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).

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. 

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Melatonin for Dogs: Possible Side Effects

Side effects of melatonin are rare in dogs, but may include^{8, 16}: 

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

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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. 

2. 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.  

3. 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. 

4. 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. 

5. 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. 

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Frequently Asked Questions