More Melatonin and Dog Cancer - Dog Cancer Blog

Featuring Demian Dressler, DVM and Susan Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide.

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More Melatonin and Dog Cancer

You want more on melatonin and dog cancer? You just hit the jackpot!

Why Melatonin?

Why should we be interested in this weird body hormone that is only generated in complete darkness?  Lots of reasons.

First of all, melatonin used with chemo versus chemo alone more than doubled the survival time of human cancer patients. That’s a big effect, folks.

Secondly, in that same study, melatonin decreased the side effects related to chemotherapy.  These included low platelet counts, irritations of the lining of the mouth (stomatitis), nervous system injury (neurotoxicity), and heart toxicity (cardiotoxicity).  Again, that is huge.

A simple hormone, produced naturally, and also cheaply found in supplement form, is related to doubled survival times and decreased side effects? That’s literally a no-brainer.

But Wait, There’s More:

Melatonin helps overcome weight loss due to cancer (cancer cachexia)  in advanced cancer patients, with no change in how much food they are eating.

As if this were not enough, a study looked at over 600 cancer patients, with a variety of solid-tissue tumors, who received melatonin.  The 1 year survival time of the group that took melatonin was more than a third greater than those that did not.

Melatonin was also the topic of a medical conference which discussed the ability of melatonin to cause some cancer cells to not only die off directly, but go back to being healthy body cells, and decrease cancer spread (metastasis). Let me restate that: melatonin seemed to not only kill cancer cells, but in some cells, to turn them BACK TO HEALTHY CELLS.

To boot, melatonin is an immune stimulator.


To put it mildly, there is lots of promising stuff here.  One of the points made at that conference was that this information has been around for years — but has not made it into the medical or veterinary knowledge pool.  (As I pointed out in the last post, I think the obvious reason is that you can’t patent it, which means no pharmaceutical company is interested … but I digress.)

Free Ways to Boost Melatonin

Obviously, dogs produce melatonin at night, in complete darkness, just like humans do. That’s why it’s a good idea to increase your dog’s natural melatonin output — and possibly even supplement it.

First, the free strategies: create a natural “den” for your dog to sleep in. Total darkness, for at least 10 hours daily can be accomplished in many ways:

  • If your dog likes sleeping “under” things, like tables, or beds, let them do it. This is their way of stimulating melatonin, by seeking dark places to snooze.
  • If your dog likes to sleep in a crate, there are fantastic covers that make it super-dark in their little cave.
  • Make your bedroom a den, particularly if your dog sleeps with you. Use blackout shades on your windows, and make sure all sources of “blue light” from TV screens, computers, tablets, and phones are removed. Stop using night lights. Make your room as dark as possible, so your dog’s brain has a real shot at generating melatonin.
  • If you can, avoid charging your devices where you sleep, because electrical fields can interfere with melatonin production. For the same reason, considering unplugging lamps and other devices at night.
  • Try some fresh sage in your dog’s cancer diet — it has lots of naturally occurring melatonin!
  • Other rich sources of melatonin are brown rice and oats, both of which are optional additions to the dog cancer diet outlined in my book.
  • Meditation — yes, meditation — increases melatonin levels. Try meditating with your dog!

Supplementing with Melatonin

Dogs vary in their natural ability to generate melatonin, and they also vary in size. Therefore, melatonin doses vary, too.

If your dog is in the early stages of dog cancer, I recommend using 1-2 mg per 40 lbs body weight, once a day, given at night.

For advanced dog cancer patients closer to the end of their life, I recommend 5 mg per 40 lbs.

You can use either tablet or liquid forms, whatever works best for your dog. Whatever form you choose, give melatonin with a little food to buffer the stomach — just a snack will do it.

I like human-grade supplements because they are manufactured to stricter standards than pet-grade supplements. Melatonin is a really inexpensive supplement, and worth trying with your dog.

Side Effects for Melatonin and Dog Cancer

Here’s the skinny on side effects and whatnot…

  • Don’t give your dog melatonin during the daytime, because it messes up their circadian rhythm and causes headaches. You probably know this firsthand if you’ve ever woken up in the middle of the night and had to turn on the light only to get very groggy and a little sick.
  • Any supplement given by mouth has the potential for digestive upset (vomiting or nausea), of course, which is why I suggest giving with a little food.
  • If your dog has any immune-mediated disease (like some types of underactive thyroid problems, dry eye, lupus, pemphigus, allergies, and so on), avoid it.
  • Don’t give melatonin to your dog if he or she is on calcium channel blockers (some types of heart and blood pressure meds), or is on fluoxetine (Prozac).
  • Because melatonin can influence metabolism, diabetic dogs may need less insulin on melatonin. So if your dog has diabetes, begin melatonin only with your vet’s close supervision and instruction. If you are not willing or able to consult with your veterinarian to manage diabetes medication, please skip melatonin. You don’t want to overdose your dog on insulin unnecessarily!
  • Melatonin being generated by the brain, I would avoid melatonin as well if your dog is epileptic.

There are statements suggesting melatonin should not be used with leukemia or lymphoma patients circulating.  I have tried to find some actual evidence for these (a paper, case report, anything real) but to no avail.  Any input from the readers?

The same is true with this idea that it can cause retinal injury. This appears to be speculation, but I am open to any documented, real evidence.

Best to all,

Dr Dressler

About the Author: Demian Dressler, DVM

Dr. Demian Dressler is internationally recognized as “the dog cancer vet” because of his innovations in the field of dog cancer management, and the popularity of his blog here at Dog Cancer Blog. The owner of South Shore Veterinary Care, a full-service veterinary hospital in Maui, Hawaii, Dr. Dressler studied Animal Physiology and received a Bachelor of Science degree from the University of California at Davis before earning his Doctorate in Veterinary Medicine from Cornell University. After practicing at Killewald Animal Hospital in Amherst, New York, he returned to his home state, Hawaii, to practice at the East Honolulu Pet Hospital before heading home to Maui to open his own hospital. Dr. Dressler consults both dog lovers and veterinary professionals, and is sought after as a speaker on topics ranging from the links between lifestyle choices and disease, nutrition and cancer, and animal ethics. His television appearances include “Ask the Vet” segments on local news programs. He is the author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog's Life Quality and Longevity. He is a member of the American Veterinary Medical Association, the Hawaii Veterinary Medical Association, the American Association of Avian Veterinarians, the National Animal Supplement Council and CORE (Comparative Orthopedic Research Evaluation). He is also an advisory board member for Pacific Primate Sanctuary.

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