Melatonin is a naturally occurring hormone produced in the pineal gland. Though most people are only aware of its use as a sleeping aid, it has many other applications when given to dogs, including the ability to help treat separation anxiety, several forms of canine alopecia (hair loss), and phobias. It can even aid in weight gain following the malnourishment associated with surgery and sickness.

Being a natural substance makes it a preferable choice for owners who wish to avoid synthetic medicines for the treatment of anxiety and insomnia. Please be aware that the use of this hormone to treat dogs is still considered “experimental” despite its apparent safety.

We recommend: For the treatment of anxiety in dogs we recommend Anxietrex, a natural remedy with no side effects. Anxietrex relieves anxiety without the rapid heart rate, headaches and itching that is possible with the use of melatonin.

Recommended Dosage

The melatonin dosage is dependent on several factors including the size of the dog and the condition being treated. It should not be used until you have spoken to your vet due to the many variables involved. The route of administration can also differ. For example, implants which slowly release the substance over time are injected subcutaneously (under the skin).


Suggested dosage plan

Atypical Cushing’s DiseaseOne 8 mg – 18 mg Dermatonin® implant every ~4 months (frequency may vary).
Insomnia or PhobiasA dosage of 0.45 mg/lb is suggested (rounding up to the nearest 1 mg), and should be given by mouth every 8 to 24 hours.

For night waking, 1 – 9 mg may be given roughly 30 minutes before bed. The amount needed will vary based on the size of your dog.
Thrombocytopenia (ITP)Because there is some evidence showing that melatonin stimulates the production of platelets, dogs with this condition could be given 3 mg if they weigh less than 9 lbs, and 6 mg if they weigh 9 lbs or over.

These doses should be given by mouth every 12 hours.

In general, when given orally, dogs under 25 lbs should receive 3 mg per dose, while those over 25 lbs should be given 6 mg per dose. Some sources recommend an even lower dose of 1.5 mg for small breeds and up to 9 mg for large breeds. Melatonin can be given with or without food.

Melatonin implant (Dermatonin)The injection of subcutaneous implants will need to be repeated several times a year. When treating atypical Cushing’s (sometimes known as Alopecia X, pseudo-Cushing’s, Nordic breed alopecia, congenital adrenal hyperplasis-like syndrome, congenital adrenal hyperplasia-like syndrome and CRFA) you can also try the oral route of administration.

The recommended dosage of orally administered melatonin for the treatment of atypical Cushing’s is 3 – 12 mg every 8 to 12 hours. Use should be continued for at least 4 months to determine whether it is effective.

What about typical canine Cushing’s disease?

According to sources including Dr. Scott Nimmo, melatonin is also useful for treating typical canine Cushing’s. Dr. Jack Oliver recommends using melatonin with lignans for this purpose.

Melatonin helps with Cushing’s by blocking the uptake of cortisone. However, if the condition is caused by a tumor on an adrenal gland, surgery is recommended.

What is the correct way to administer a subcutaneous shot?

When it comes to administering shots subcutaneously we recommend following your vet’s directions. Some vets will have you come into the clinic and perform the injections themselves, but if not, there are several helpful videos on YouTube which show you how to do it yourself. Don’t forget to sterilize the injection site and change the needles after use to minimize the chance of infection.


How Safe Is It?


Melatonin is produced naturally by a part of the brain known as the pineal gland.

There is not much information regarding the safety of melatonin when given to dogs. However it is a substance naturally produced in the body and appears very safe, with few reports of side effects (even during longer term use – although a decrease in lutropin levels can be expected in these cases).

Many vets have successfully and safely used implants to treat atypical Cushing’s with no adverse reactions, and each implant can last up to 4 months at a time.

Pregnant pets and very young puppies (12 weeks and under) should not be given melatonin. Based on human contraindications, it is also advised that you notify the vet if your dog suffers with liver problems, issues affecting the brain, bleeding disorders, seizures, or poor kidney function. Because melatonin can slow the blood clotting process, it’s best to avoid use alongside other drugs with anticoagulant properties such as aspirin.

Safety Guidelines

To increase the safety of treatment you should always speak to the vet before giving melatonin to your dog. You should disclose any medical conditions your dog suffers with and any other medicines/supplements he or she is taking. If you are planning to use subcutaneous implants, make sure you understand the guidelines of safe injection and avoid accidentally injecting the substance into muscle tissue or the bloodstream. In most cases the vet will inject the implants for you.

If your pet is suffering from hair loss it’s strongly recommended that you seek a diagnosis, as this symptom is associated with various conditions including thyroid disease, parasite infections, and bacterial infections, all of which require other forms of treatment.


There are several possible uses of melatonin for dogs. It can be used to treat:

  • Atypical & Typical Cushing’s
  • Insomnia
  • Phobias
  • Anxiety
  • Thrombocytopenia (ITP)

Owners should remember that insomnia is often brought on by emotional distress or physical pain (for example, pain associated with arthritis). We recommend trying to find the underlying cause and treat that instead of masking the issue with supplements. Some key things to consider are recent moves, new tenants, emotional tension in the household, and the age of your pet (because old age increases the likelihood that he or she is suffering from joint-related pain).

If you suspect arthritis take your dog to the vet for a professional opinion. Supplements such as Dasuquin® (containing glucosamine, chondroitin and MSM) are better choices than melatonin for treating joint pain as they can address the cause of the issue instead of masking one of the symptoms. By relieving your dog’s pain, not only will he get a better night’s sleep, but he will also be able to enjoy a more active lifestyle during the day.

Side Effects

When given orally, adverse effects appear to be rare. However, based on the reports of owners and the side effects seen in humans, the following should be anticipated:
Most Common

  • Sleepiness


  • Changes in fertility
  • Rapid heart rate
  • Stomach cramps
  • Headaches
  • Itching
  • Confusion
  • Gastric upset

If subcutaneous implants are used, abscesses are also possible. These are abscesses which develop around the injection site where the drug has remained and caused irritation.


In the case of an overdose please get in contact with your vet for advice on how to proceed. You may also call the ASPCA poison control hotline on (888) 426-4435. Mild overdoses are not expected to result in complications beyond an increase in sleepiness and stomach discomfort, but could potentially result in more serious issues such as high blood pressure and seizures in susceptible pets. It’s best to practice caution and seek help when an overdose is suspected due to the limited knowledge regarding melatonin use in animals.


Dr. R. Paradis
Plumb’s Veterinary Drug Handbook (sixth edition)