Can I Give My Dog Melatonin? Help for Hair Loss

Can I give my dog melatonin? You may be asking yourself this if your dog is suffering from hair loss and you are looking for solutions. The answer ultimately lies with your vet, so to aid in that discussion, integrative veterinarian Dr. Julie Buzby provides information about when your vet might recommend using melatonin for dog hair loss. Plus, she answers a few FAQs about giving dogs melatonin.

Watching your dog’s once full and beautiful coat start to become scraggly or patchy due to hair loss can be difficult. Each time you pet your dog or snuggle him or her, you may be reminded of the fact that, despite your vet ruling out the common culprits like allergies, infections, and parasites, the exact cause of your dog’s thinning fur remains uncertain.

In this situation, your vet may recommend giving your dog a melatonin supplement. While it isn’t effective for most skin issues in dogs, melatonin, a naturally occurring hormone that is also available as a supplement, can work wonders for dogs with hair loss due to conditions like seasonal flank alopecia or alopecia X (hair cycle arrest).

What does melatonin do for dogs?

Melatonin is a hormone produced by the pineal gland in the brain in response to darkness. One of its most significant roles is regulating sleep-wake cycles to help animals (and people) maintain circadian rhythms. However, melatonin may also be used in veterinary medicine for decreasing anxiety, managing some autoimmune or endocrine disorders, and even assisting with cancer treatment.

Plus, as you are about to discover, melatonin provides hope and help for dogs with certain types of hair loss.

Can I give my dog melatonin for hair loss?

If your dog is losing hair, speak with your veterinarian. In general, if your dog has seasonal flank alopecia or alopecia X, melatonin may help promote hair regrowth. But it doesn’t work for all conditions that cause hair loss.

Let’s take a closer look at why this is the case. Melatonin helps regulate seasonal shedding cycles—where animals lose their winter coat in the spring and grow a thick coat in the winter.⁴

We know that melatonin levels increase with exposure to darkness. It makes sense, then, that we can see seasonal changes in systems that are affected by melatonin—such as the skin and fur—as the days get shorter or longer. Higher melatonin levels in the fall and winter promote the growth of a winter coat. Lower levels in the spring and summer stimulate shedding of that coat.

How does melatonin help with hair growth?

The mechanism by which melatonin is involved in regulating hair growth is not fully understood. However, research in humans and animals indicates that melatonin may promote hair growth by: ^3,4,8

• Controlling how sensitive the hair follicles are to changes in hormones (especially reproductive hormones)
• Turning on and off the necessary genes to produce keratin (the substance that makes up hair) and make more dermal papillae cells (the cells that help manage the hair growth process)
• Promoting the anagen (growth) phase of the hair cycle. The other phases of the hair cycle are catagen, which is the transition between growth and rest, and telogen, the resting phase where the hair remains in place but is not growing. After telogen, a new hair pushes out the old hair, and the cycle repeats.
• Delaying shedding and extending the growth phase
• Protecting the hair follicle and promoting overall hair health (melatonin accomplishes this via its antioxidant properties).

It is also possible that melatonin can influence the levels of other hormones in the brain that play a role in controlling hair growth, such as prolactin and melanocyte-stimulating hormone.

Two causes of hair loss that can be treated with melatonin

In dogs, melatonin may help manage two conditions that cause hair loss—seasonal flank alopecia and alopecia X. In both cases, the condition is considered cosmetic. The dog either has a thinner fur coat than usual or has lost fur entirely. Dogs with these conditions are typically not itchy, and their skin is not inflamed.

However, there are other diseases where hair loss can occur in the absence of itching or inflammation. Two examples are hypothyroidism in dogs and Cushing’s disease in dogs. It is essential that the vet rule out these conditions prior to relying on melatonin as a primary treatment.²

Melatonin and seasonal flank alopecia

Seasonal flank alopecia typically occurs in dogs in northern regions (at or above the 45° parallel) such as the upper Midwest, Northeast, and Canada. However, dogs in both the northern and southern hemispheres can potentially have seasonal flank alopecia.

As the name implies, affected dogs tend to symmetrically lose the hair on their flanks. Plus, they may have some hair loss on their back. The skin typically becomes hyperpigmented (darker or black) but is not red, inflamed, or itchy. Signs usually start in the fall, and the haircoat grows back about six months later in the spring.

Certain breeds seem to be predisposed to this condition², including:

• Boxers
• Bulldogs
• Airedale Terriers
• Doberman Pinschers
• Scottish Terriers
• Labrador Retrievers
• Giant Schnauzers
• Akitas

Researchers believe that the reduced exposure to light in the winter months may play a role in hair loss.² Melatonin has been shown to help improve hair coat and promote hair growth in some cases. However, cases may also resolve on their own during the spring and summer as the daylight hours increase.^2,3 If your dog is showing seasonal hair loss, ask your vet if melatonin may be a good treatment option.

Interestingly, while seasonal flank alopecia typically reoccurs each year, about 20% of affected dogs will only have one episode of it. For dogs who tend to get flank alopecia each year, starting a melatonin supplement about one to two months before hair loss usually occurs can sometimes be beneficial.

Melatonin and alopecia X

Alopecia X (hair cycle arrest) will generally start out with the coat becoming more “puppy-like” or fuzzy due to the loss of guard hairs. The fur may also seem drier or dull. Over time, affected dogs lose hair in areas of friction like the neck and tail. Then the hair loss progresses to involve the area under the tail, rear portion of the thighs, and back half of the trunk as well. Typically, the fur on the head and lower legs will remain unaffected. The skin may be darker (hyperpigmented) but not inflamed.

We see alopecia X more commonly in Nordic breeds³ with double coats, such as:

• American Eskimo dogs
• Chow Chows
• Pomeranians
• Alaskan Malamutes

Although the exact cause is unknown, it may be related to a hormone imbalance. This is because spaying and neutering intact dogs has been shown to cause the hair to regrow.³ In patients who are already spayed and neutered, melatonin is often the first-line treatment for alopecia X. This is the case in part because the potential side effects of melatonin are usually milder than those for other treatment options.

In one study using melatonin to treat alopecia X in Pomeranians, 40% of dogs did experience mild to moderate regrowth of hair after three months. However, there were only 15 dogs in the study, so the sample size was very small.

Melatonin and dogs: FAQs

At this point, if you’re thinking your dog may benefit from taking melatonin to manage one of these conditions, you may have a few follow-up questions. If so, check out these melatonin FAQs, then talk with your veterinarian about your dog’s particular situation.

Can I give my dog melatonin?

Before you decide to start giving your dog melatonin, it is essential to consult your vet. He or she can confirm that melatonin is an appropriate choice for your dog and his or her condition. Plus, the vet can recommend the correct dose of melatonin and discuss how to find a good melatonin supplement.

In general, veterinarians may consider melatonin for dogs for a variety of conditions, not just hair loss. It is great for helping dogs with canine cognitive dysfunction and blind dogs who are having sleep issues re-establish normal sleeping patterns. Plus, it is beneficial for anxious or nervous dogs, especially when combined with other medications and tools for managing anxiety. Melatonin may also play a role in treating immune-mediated thrombocytopenia (ITP in dogs) and certain types of cancer.

Another great thing about melatonin is that its side effects are usually mild (most commonly sleepiness or GI upset), and it is safe for most dogs. However, it is contraindicated in dogs with liver or kidney problems or diabetes in dogs and should not be used in breeding or working dogs. Plus, it can interact poorly with supplements or medications that raise serotonin levels.

How much melatonin can I give my dog?

There is no one-size-fits-all dose for using melatonin to treat various conditions in dogs. How much your dog weighs, which condition your vet is treating, and your dog’s health history all influence the correct dose of melatonin for your dog.

Also, I never recommend starting a medication without talking to your veterinarian to determine whether it’s safe or appropriate for your dog. If your vet feels that your dog is a good candidate for melatonin supplements, he or she will recommend the correct dosage.

Can I give my dog melatonin supplements?

The answer to whether or not you should give your dog a melatonin supplement ultimately lies with your vet. Many dogs can take melatonin supplements that are formulated for dogs or formulated for humans, as long as they are free from xylitol. Some human melatonin products, especially gummies, may contain xylitol (birch sugar), which is toxic for dogs. If you want to give your dog a human melatonin supplement, it is crucial to read the label to ensure it does not contain xylitol.

Additionally, it is important to remember that the FDA does not regulate supplements. Thus, there can be a lot of variation in the quality and contents of the supplement. When selecting a melatonin supplement, it helps to look for one that has the NASC (dog products), USP, or NSF (human products) seal of approval. They are the most likely to contain the amount of melatonin specified on the label and be of good quality.

Nature’s Bounty® melatonin 3 mg tends to be a popular option among many veterinarians. And I use Thorne® Melaton-3™ Dietary Supplement for my own family. However, it is crucial to pick a quality product formulated for humans or dogs that is free from xylitol and approved by your veterinarian.

Can dogs have melatonin gummies?

No. Dogs should not have melatonin gummies. They are the form of melatonin supplements that are the most likely to contain xylitol (birch sugar), which is poisonous to dogs.

It is critical that dog owners avoid formulations of melatonin that contain xylitol because it can cause dangerous or even fatal low blood sugar and liver failure in dogs. Gummies are the biggest culprit. While melatonin itself is very safe, xylitol is HIGHLY toxic to dogs. 

Will melatonin make my dog sleepy?

Since vets may use melatonin to manage sleep disorders (usually dogs not sleeping at night), there is a good chance it could make your dog a bit more sleepy, sluggish, and/or subdued. If you feel your dog is overly tired, stop giving the melatonin and consult your veterinarian.

Melatonin worked wonders for my Pomeranian patient

Finally, since I like to talk about dogs and not just conditions, let’s meet a 4-year-old neutered Pomeranian named Elvis. Despite having a doting owner who adored him, Elvis looked like he’d been rescued from a grooming incident that had gone awry. He had a mane of rust-colored fur around his neck, but his body was bald. Patches of his skin had turned to a blackish leather, and his tail looked like that of an opossum with mange.

We did a full workup with labs to try to get to the bottom of what was causing Elvis’s hair loss. All of his bloodwork results pointed away from the “normal” dog endocrine diseases, which can cause hair loss—like Cushing’s disease in dogs and hypothyroidism—and toward a diagnosis of alopecia X.

Marvelous melatonin to the rescue

We started Elvis on oral melatonin. I explained to his mom that we would commit to a three-month trial before making any further changes. It took over four months until Elvis had the coat of a normal Pomeranian, but he regrew his hair! It was somewhat stunning to behold.

Speak with your veterinarian if your dog is losing hair

If you are noticing your dog is losing hair, the first thing you should do is make an appointment with your veterinarian. There are many causes of hair loss in dogs, and most of them have solutions that are NOT melatonin. Being able to distinguish those problems from the ones that are responsive to melatonin—alopecia X and seasonal flank alopecia—is important so your dog gets the care he or she needs.

If your vet does feel that your dog might benefit from melatonin, follow his or her directions regarding dosage and product selection. And follow up with your vet periodically so that he or she can re-evaluate your dog and make any necessary changes to the treatment plan.

Finally, lest you be tempted to skip the vet visit and start melatonin on your own for your dog’s hair loss, please reconsider. I strongly urge all pet owners to talk with their veterinarians before starting any additional medications or supplements. Melatonin is no exception. It does work well in the right circumstances, but it isn’t a substitute for veterinary care.

What questions do you have about melatonin?

Please comment below. We can all learn from each other.

Sources:

1. Byers, C G. “Just Ask the Expert: Is There a Role for Melatonin in Dogs and Cats with IMHA?” DVM360, 27 July 2017, veterinarymedicine.dvm360.com/just-ask-expert-there-role-melatonin-dogs-and-cats-with-imha.
2. Jeromin, A M. “Seasonal Affective Disorder Can Be Culprit for Canine Hair Loss.” DVM360, 1 Apr. 2003, veterinarynews.dvm360.com/seasonal-affective-disorder-can-be-culprit-canine-hair-loss.
3. “Melatonin and Seasonal Alopecias.” Veterinary Practice, 1 Nov. 2013, veterinary-practice.com/article/melatonin-and-seasonal-alopecias.
4. “Melatonin.” Plumb’s Veterinary Drug Handbook, Veterinary Information Network, 1 Jan. 2015, www.vin.com/members/cms/project/defaultadv1.aspx?id=4692338&pid=451&.
5. “Melatonin.” VIN Veterinary Drug Handbook, Veterinary Information Network, 30 June 2017, revised 02 December 2024, www.vin.com/members/cms/project/defaultadv1.aspx?pId=13468&id=7868548.
6. “Melatonin: Side Effects, Uses, Dosage (Kids/Adults).” Edited by L Anderson, Drugs.com, 26 Mar. 2019, www.drugs.com/melatonin.html.
7. Reiter, R J, et al. “Melatonin, a Full Service Anti-Cancer Agent: Inhibition of Initiation, Progression and Metastasis.” Int J Mol Sci, vol. 18, no. 4, 2017, doi:10.3390.
8. Tawanwongsri, W, Eden, C. “Melatonin for hair regrowth: Preclinical insights, current evidence, and future perspectives”. Electron J Gen Med. vol. 22, no. 4, 2025, doi: 10.29333/ejgm/16520

This post was originally published on October 31, 2022 and updated on October 13, 2025.