Benefits And Uses Of Melatonin In Dogs

Julia Henriques
Benefits And Uses Of Melatonin In Dogs

Melatonin is a well-known natural hormone. People take supplements to fight jet lag or insomnia, because it helps regulate the body’s sleep-wake cycle. It’s important to promote natural melatonin in dogs as well as humans. In fact, according to Dr Patricia Jordan DVM, “melatonin may be the single most important substance in your dog’s body.”

Dogs naturally make their own melatonin, but it can be depleted.

How The Body Makes Melatonin

It all starts with the pineal gland, which regulates the sleep-wake cycle. The pineal gland secretes melatonin at night, so it’s also known as the hormone of darkness

The Journal of Pineal Research explains that melatonin can cross the blood-brain barrier. So  melatonin secreted by the pineal gland enters every cell in the body. However, the pineal gland isn’t the only body part producing melatonin. The hormone also comes from the intestinal lining, salivary glands, stomach lining and esophagus. 

In fact, in 2017, French researchers (1) found that …

  • There’s 400 times more melatonin in the gastrointestinal tract than the pineal gland
  • Digestive tract melatonin levels are 10-100 times higher than in blood
  • Melatonin deficiency can increase inflammation throughout the body, depleting the immune system and increasing the risk of chronic diseases.

This means melatonin benefits go far beyond helping with sleep issues.

Why Melatonin Gets Depleted

Melatonin deficiency means the body doesn’t produce as much melatonin as it should. Several factors can cause this problem. 

Glyphosate, the herbicide also known as Roundup, depletes melatonin. It’s impossible to avoid glyphosate in the environment.  MIT Scientist Dr Stephanie Seneff PhD found that glyphosate interferes with the ability of gut bacteria to make the amino acid tryptophan. Tryptophan is a building block for both melatonin and the mood-regulating hormone serotonin. Serotonin also helps make make melatonin. Because glyphosate is used on crops, it gets into the food and water supply so it can cause melatonin deficiencies.

Eating organic foods and not using chemical herbicides can help reduce your dog’s glyphosate exposure. 

Artificial Light. Before electricity, humans slept when it was dark and woke up when it was light. Light suppresses melatonin production. Electric light confuses the body so it doesn’t produce melatonin when it gets dark outside. Compact fluorescent lightbulbs can suppress melatonin production by 40 percent. 

Try to keep your household on a sleep schedule that’s close to natural night time hours if you can! 

Lack Of Daylight. Natural light is also important, so make sure you get your dog outside in the daytime as much as possible.

Electromagnetic Radiation (EMR) also depletes melatonin levels. Wi-Fi, cell phones and cell phone towers, computers, cordless phones, smart meters and antennae all emit harmful EMR. One way to decrease EMR exposure is to turn off your wireless router at night and when you’re not home. Any little change can make a difference.

Other causes of melatonin depletion include: stress, lack of sleep, certain pharmaceutical drugs, smoking or secondhand smoke, and leaky gut syndrome.

Some suggest that melatonin production decreases with age – which could explain why dogs and older humans sometimes sleep less during the night time.

How To Boost Natural Melatonin In Dogs

There are many ways to encourage natural melatonin production before you resort to melatonin supplements. Most melatonin supplements are synthetic, so it’s best to only use them if they’re truly needed.

Foods that are rich in tryptophan that help boost melatonin:

  • Grass-fed meats
  • Wild game
  • Fresh eggs from pasture-raised chickens
  • Wild fish
  • Raw milk from grass-fed cows for dogs that tolerate dairy
  • Pasture-raised poultry

Vegetables (asparagus, broccoli and Brussels sprouts, in particular) and calcium-rich foods like sardines, dark green leafy vegetables and raw meaty bones can help with melatonin production. Fruits are a good choice, especially bananas, pineapple and tart cherries (remember to remove the pits first!). Feed fruit in moderate amounts because of the sugar content. 

Organic food is always best, and paired with good sleep routines should help your dog produce more melatonin. Get plenty of daytime walks, sleep with as few electronics as possible in the room, dim lights in the evening and sleep in darkness.

How Melatonin Benefits Dogs

Melatonin is important for dogs. It can help manage digestive issues, depression, cognitive disorders, insomnia and anxiety. Holistic veterinarian Dr Patricia Jordan DVM recommends melatonin for some of the following problems. 

If you notice your dog is anxious or fearful, melatonin can have a calming effect. This is especially helpful for separation anxiety issues, thunderstorms or fireworks with dogs who are fearful of loud noises.

Insomnia Or Restless Sleep
If your dog doesn’t sleep through the night, and is often sluggish during the day, he might need melatonin to regulate his sleep-wake cycle, which will help him to be more alert when awake.

Cognitive Disorders
Canine cognitive dysfunction is a common disorder in older dogs, and one that Dr Jordan often uses melatonin to help with. It calms older dogs and helps regulate their sleep cycle.

Gut Health
In 2018, Chinese researchers investigated the role of gut health in managing insomnia, circadian rhythms and depression. The study was done with mice, and showed that melatonin promoted good gut bacteria, and helped with bowel movements, diarrhea, constipation, yeast, and leaky gut syndrome (2).

Immune Support
A 2013 study at University of Sevilla, Spain. discovered that melatonin buffers the immune system, helping with inflammation and autoimmune conditions … and that many animals have melatonin receptors (3). 

Melatonin can help decrease seasonal hair loss called alopecia (4). Alopecia is common in dogs in the spring, so it may be due to lack of sunlight during the winter months. 

Other Melatonin Benefits In Dogs
The antioxidant effect of melatonin helps protect the liver, the kidneys and the brain. It also helps decrease inflammation in the lungs. It helps with thyroid disease, can may help lower blood pressure, decreasing damage from oxidative stress. 

Melatonin may help prevent cancer as well as a wide range of diseases, and it slows down the aging process. Melatonin is a hormone that protects the mitochondria (the powerhouse of the cells). Melatonin may also prevent bone loss, as shown in a 2013 study on rats at Madrid University (5).

Melatonin Dosing In Dogs

Natural melatonin created in the body is the most effective. So the best approach is to make dietary and lifestyle changes as described earlier.

But if these changes don’t help, you may want to check with your holistic veterinarian about whether melatonin supplements might help.

The correct dosing for melatonin supplements, widely recommended by veterinarians is … 

  • 1.5 mg for dogs under 25 pounds
  • 3 mg for dogs 26-99 pounds
  • 6 mg for dogs over 100 pounds

Dose these amounts once or twice daily. If you’re giving it once a day, give it in the evening.

Cautions With Melatonin Supplements In Dogs

At low doses, between .5 mg and 5 mg, there are very few side effects of melatonin. However, it’s best to use it only short term. Don’t give it to pregnant or lactating animals.

Buy From A Reputable Source
Always buy your melatonin supplement from a reputable supplier, preferably third party tested. According to the National Institutes of Health (NIH), some studies show that melatonin supplements don’t always contain what they say they do. A 2017 study that tested 31 melatonin supplements found the amount of melatonin in the product didn’t match the label claims in most of the products.

Some melatonin supplements have additional ingredients like serotonin, which can be harmful. In the above study cited by the NIH, 26% of the supplements tested contained serotonin. Other supplements may contain fillers or sweeteners. Never use any product with xylitol, which is deadly to dogs. 

Melatonin can interact with some drugs so don’t use it if your dog is taking any of these medications:

  • Diabetes medicine
  • Immunosuppresants or steroids
  • Anticonvulsants
  • Anticoagulants or anti-platelet drugs

Dr Jordan calls melatonin “our biggest multitasking chemical.” It’s an important hormone for your dog so make sure you use the lifestyle changes and melatonin-promoting foods recommended above, so he produces it naturally if he can.


1. Tordjman S, Chokron S, Delorme R, et al. Melatonin: Pharmacology, Functions and Therapeutic BenefitsCurr Neuropharmacol. 2017;15(3):434-443. 

2. Li Y, Hao Y, Fan F, Zhang B. The Role of Microbiome in Insomnia, Circadian Disturbance and Depression. Front Psychiatry. 2018;9:669. Published 2018 Dec 5. 

3. Carrillo-Vico A, Lardone PJ,  et al. Melatonin: buffering the immune system. Int J Mol Sci. 2013;14(4):8638-8683. Published 2013 Apr 22. 

4. Frank LA, Hnilica KA, Oliver JW. Adrenal steroid hormone concentrations in dogs with hair cycle arrest (Alopecia X) before and during treatment with melatonin and mitotaneVet Dermatol. 2004 Oct;15(5):278-84. 

5. Tresguerres IF, Tamimi F,  et al. Melatonin dietary supplement as an anti-aging therapy for age-related bone loss. Rejuvenation Res. 2014 Aug;17(4):341-6.

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