Joint supplements for pets such as glucosamine and chondroitin (e.g. Cosequin) have been around for over two decades. Owners have been giving their arthritic canines and cats that, as well as other supplements that humans take like omega 3 and curcumin from turmeric.

While not always cheap, this makes a lot of sense. Being that we are all mammals, their bodies can benefit in ways similar to ours. The exception being vitamin C, as canines and felines (as well as most mammals) produce it internally. We as humans, along with rabbits and a few other herbivorous animals, are required to get vitamin C from dietary sources.

The only reason CoQ10 was never classified as a vitamin is because our bodies produce it internally and therefore, it’s not needed from external sources. By definition, a vitamin is something humans need to get from food or an external stimulus, like the sun spurring vitamin D production. While technically correct, it masquerades the importance of coenzyme q10, which is found inside every living cell of the body.

This molecule plays a crucial role in the adenosine triphosphate (ATP) energy production cycle, which takes place inside of the mitochondria.

natural rates of CoQ10 decline from agingSure our bodies make it, but the peak production is around age 19-21. After that, we produce less and less as we we get older. As you see in the chart, by the time you’re 80, your heart may only have around 40% of the peak amount.

For a 65 year-old man who doesn’t supplement, their blood serum concentration might be around 0.65 micrograms per mL. An estimate of about half the 1.37mcg they had when they reached legal drinking age. (1) (2)

Being that your pet is carnivorous, it is true they get more of this coenzyme from their diet than a person. Regardless, even if they were eating the best food sources (i.e. reindeer meat) the amount of CoQ10 they would be getting would be pitiful relative to what even a low dose supplement offers.

Whether they’re for humans or pets, you will see both ubiquinone and ubiquinol supplements for sale. While both are good, it’s the ubiquinol form which research has found to be better.

Our bodies can convert ubiquinone (the oxidized form) to ubiquinol (the reduced form) and vice-versa. Both forms are required for the ATP energy production cycle within the cells. Yet human studies suggest that the reduced, active antioxidant form – ubiquinol – is the more bioavailable form for CoQ10 you’re getting from supplementation. (3)

Can you give CoQ10 to dogs? (or cats?)

From the smallest bacteria to the largest animals, almost all life forms produce CoQ10 internally. There is limited research looking at how much dogs make and the rate at which it decreases with age. You can give it to your dogs and it appears safe, however it’s unknown if it helps their health as much as humans.

hand feeding dogNearly two decades ago, in the year 2000, the Mayo Clinic published a study of using it on dogs with congestive heart failure that was tachycardia-induced. That means it was caused by tachycardia (a fast heart rate) or arrhythmia (an irregular heart rhythm).

Some were given CoQ10 supplements while others were not. Even though it appeared to help with the hypertrophic symptom (enlargement of the heart) there wasn’t a CoQ10 deficiency seen in the animals, nor were dramatic benefits observed with hemodynamics (blood flow). (4)

Now that was a small study, with only 5 animals treated, 5 untreated, and 5 without congestive heart failure as a control group. It may be too small of a study.

In 2017, there was a much larger study with a total of 72 dogs. Out of those, 29 were healthy and 43 had various types of congenital and acquired cardiovascular disease.

None were given supplements, as the researchers were just trying to find a correlation for natural CoQ10 blood levels and other internally created antioxidants.

The findings?

“A significant, negative correlation between serum NT-proBNP and plasma CoQ10 concentrations was identified in treated CHF-affected dogs, suggesting that low plasma CoQ10 concentration may be associated with increased severity of CHF.”

In plain English, there might be a link. Dogs with both mild and severe heart disease appeared to have lower amounts of CoQ10 in their blood. (5)

There is peer-reviewed published research from veterinarian scientists in France, Russia, China, Japan, the U.S. and elsewhere, all suggesting that giving dogs CoQ10 is beneficial. Some say you should give it to cats, too. Even without knowing for certain whether there is a deficiency present, reasons cited include the fact that during heart failure, there are higher amounts of free radicals produced which cause increased oxidative stress and cell damage. (6) (7) (8)

cavalier king charles spaniel

Not to be confused with Cocker Spaniels, this is what a Cavalier King Charles Spaniel looks like

Sometimes called leaky valves, the condition of heart murmurs can be detected with a stethoscope. There is an unusual sound between the beating. Some breeds, like Cavalier King Charlie Spaniels, are more prone to getting them. Hyperthyroidism in cats is another common cause.

Most often, these murmurs are caused by structural heart valve abnormalities, such as small holes, closures which don’t seal 100%, valve calcification, and endocarditis, which is a heart infection.

Given their lifestyle, the latter is frequent in pets. One type of infection is heartworm, which is caused by a parasitic roundworm spread through mosquitoes. It will lead to cardiac damage and possibly premature death if untreated.

Whatever the cause, heart murmurs in humans, dogs, and cats have not been studied and it’s unlikely that CoQ10 would help, as many of the causes are structural defects of the organ itself. That said, it probably won’t hurt to give your pet this supplement, since it may benefit their health in other ways.

The same applies to cancer. If your Labrador Retriever has tumors, then CoQ10 won’t do anything to help that disease. It might help support overall health, though one shouldn’t be misled into thinking that it will prolong their life or delay/cure the cancerous growths.

You will see some canine kidney support supplements on the market that include it in their formulation. There are no studies about giving CoQ10 to dogs with kidney failure or other renal diseases. Based on human studies, there isn’t yet compelling evidence that it helps. Supplementation with omega 3 fatty acids appears to be more beneficial during kidney disease. (9)

In a 2015 published study out of Australia, omega 3’s were shown to reduce high blood pressure in human renal failure patients. The same benefit was not seen in the CoQ10 treated group. Similar results were also observed in a 2009 study. (10) (11)

On the flip side, there was a study in 2008 monitoring 36 kidney dialysis patients who were given supplements and it was concluded that (12):

“The CoQ10 administration was partially effective for suppressing the oxidative stress in hemodialysis patients. The unexpected decrease of ORAC and TEAC [methods of measuring free radical activity] by CoQ10 seemed to be associated with a decreased oxidative stress.”

How much CoQ10 to give a dog?

If you take this supplement yourself, you already know it’s commonly sold in 100 and 200 mg softgels. They are typically recommended for 2-3 times per day with meals, though some cardiologists recommended advise their patients to take even higher amounts.

blue-eyed Siberian Husky

This Siberian Husky may be almost as heavy as a small lady, but most pets will only be a small fraction of the average person’s weight.

Unless you own a Great Dane, Neapolitan Mastiff, Rottweiler, or other large breed, chances are that you may be 2-5x heavier than your furry friend. For a small breed, such as a Shih Tzu or Yorkshire Terrier, you could be a slim person and still weigh 10 or even 15x their weight! Likewise for puppies.

Obviously, dosages for humans will be different. Fortunately there is some research on safe ubiquinone and ubiquinol dosages for dogs.

A safety and bioequivalence study was done with beagles using 30 mg ubiquinone doses. Both the powder-filled and liquid (oil-based) capsules showed “poor and slow absorption characteristics” based on blood levels. Since ubiquinol Coq10 shows better absorption in humans, it’s probably the better dosing choice for dogs, too.

Male beagles weigh 22-24 lbs, while the females average 20-22. If they were given 30 mg safely, we can conclude at the very least, that amount is safe for mid-sized breeds. (13)

That study was out of a university in Louisiana. On the other side of the world, in Slovenia, they also tested beagles, but using a water-soluble form of ubiquinone CoQ10 made by the German-based Chemical company, BASF. Here’s a chart of blood serum levels in the dogs after getting a single 30 mg dosage…

chart showing 30 mg dosage in dogs over period of 48 hours

As you see, a couple hours after ingestion, their levels peaked at around 1.2 mg/L, which is the same as 1.2 micrograms per mL. You may recall from above that in humans, the peak concentration has been estimated to be around 1.37 during the late teen and early 20’s age range.

There isn’t research as to whether or not dogs have a similar peak concentration, but the fact that it increased substantially in this study – boosted 2-3 times higher – is a positive sign for those wanting to give their dogs and cats this supplement. Remember this was the water soluble form of ubiquinone that had good absorption, regular ubiquinone remains an inferior choice. (14)

“The results show that water-soluble formulation presents a strongly improved absorption and we expect that the inclusion complex will soon be used as a basic food and fodder additive, especially in products with reduced amount of fat.”

If 30 mg is good, are higher dosages still safe and healthy?

average Beagle

Your average Beagle isn’t tiny, yet no one would call it a large breed.

Massachusetts General Hospital did a toxicity study in 2012, also using beagles. Now they weren’t testing it for veterinarian purposes, but rather because they were trying to determine if it’s safe to give humans high dosages.

These little dogs were given VERY high dosages, ranging from 600 to 2,400 mg per kilogram of body weight. Considering that 24 lbs equals 11 kg, that means up to 26,400 mg per day!

Ubiquinone, not ubiquinol, was the type used. It was administered to them by oral gavage for a total of 4 weeks.

A couple of the dogs experienced side effects of vomiting on day 2 and 3, yet interestingly enough, that was with 3 dogs in the low dose group of 600 mg and 1 dog in the 1,800 mg. There was no vomiting with the highest dosage of 2,400 mg/kg. Aside from that mishap at the start, no adverse effects were seen. There were no changes in body weight and food consumption. That was during a 4-week period.

Next, they did a 39-week toxicity study. For this one, they left off the highest dosage and only used up to 1,800 mg/kg.

“Behaviors, blood chemistries and detailed histopathology were normal. No deaths occurred. These results support the use of a 2400mg/day dosage of CoQ10 in human clinical trials.”

bar graph showing CoQ10 levels in beagles over 28 days of taking supplements

We know it was being absorbed too, because the amount detected correlated with the dosing level, as seen in this graph. As you see, the absorption was in dose-dependent manner up until 1,800 and after that, taking more (2,400) actually led to less absorption. That’s why during the 39-week study, they only took up to 1,800. (15)

Kaneka, the patent-holder on the manufacturing process of ubiquinol, has done studies on both rats and beagles, to try and gauge how much might be too much CoQ10. Or what amount might be poisonous and lead to dangerous adverse reactions.

Based on the conditions of that study, they estimated that “more than 600 mg/kg/day” in both the male and female dogs was within the NOAEL (no observed adverse effect level). (16)

“…there were no deaths or ubiquinol-related toxicity findings during the administration period. No test article-related effects were observed in body weight, food consumption, ophthalmology, electrocardiogram, urinalysis, hematology, or blood chemistry. Histopathological examination revealed no effects attributable to administration of ubiquinol or ubiquinone in any organs examined.”

To reiterate, they were not talking about 600 mg per day, but rather 600 mg per kilogram of body weight per day.

For an 11 kg beagle, that was 6,600 mg of ubiquinol every day, consecutively used for 13 weeks. Whether that was good or bad for them remains unknown, yet no side effects were observed with that dosing.

The takeaway?

As with humans, no one knows exactly how much CoQ10 is too much or the optimal dose to take. However this is not a phytonutrient that builds up in your liver like vitamin A, E, and other fat-soluble substances. Those you can easily overdose on. With CoQ10, the research to date suggests that both humans and animals only circulate it for hours, not days. During that short period of time it’s either getting used, broken down, or excreted. No one can say for sure exactly what happens to it in the body, yet even relatively high amounts have appeared safe in human trials, as well as rat and canine research.

No studies involving felines have taken place, though one can hypothesis that the trend with cats would be similar.

Reviews of CoQ10 for pets

Ubiquinol is identical regardless of the brand on the bottle. That’s because all ubiquinol is manufactured by the Japanese company, Kaneka, who in turn sells the softgels to supplement companies.

Whether it’s Qunol Mega, which is the red label version that is the most expensive line from Qunol, or ubiquinol from cheaper brands like Jarrow Formulas, Doctor’s Best, and Kirkland Signature, all of these are the same active ingredient, made by the same company (Kaneka).

Regular ubiquinone is the inferior version and while it is not patented, some formulations of it are, where they combine the molecule with other substances to make it more bioavailable. The water-soluble version is one such example and that one is a good option.

Veterinary CoQ10 supplements are also molecularly identical to the human formulations, at least for their active ingredient. So your first inclination may be to buy supplements for humans, as they might offer a higher dose for less money than the bottle marketed for pets. Not to mention, finding where to buy dog CoQ10 is an uphill battle. We have actually never seen it for sale at any physical store.

The temptation to use human supplements is understandable, but doing so could be dangerous for your dog or cat!

For starters, you don’t want to torture your pet by forcing capsules and softgels down their throats. Even if it saves you money, that’s fairly cruel if you can easily avoid doing so with alternate versions.

Buying liquid CoQ10 that’s for people and giving to your German Shepherd may seem like the cost effective solution, though it may result in major side effects.

warning about using CoQ10 for pets because of xylitol

Many liquid forms contain xylitol and other sugar alcohols, which are dangerous to your pet’s digestive system. They stimulate the animal’s pancreas to release too much insulin, resulting in seizures, coma, and even death. (17)

On a related note, many sugar free candies and foods contain xylitol. Don’t feed them to your pets!

NOW Foods liquid CoQ10 contains xylitol. The brand MRM (pictured at start) did not have xylitol in it, yet the “natural flavors” and other added ingredients may or may not be ideal.

The lesson is that you can’t necessarily just take a human version and give it to Fido.

Rather than torture them with capsules you need to shove down their throats, or risk dangerous liquid formulations, your safest bet is to buy ones specifically for dogs even if they do cost more.

VetriScience Conzyme Q10 dog & cat supplement is one of the bestsellers on the market. It’s safe for them, but it’s only 10 mg of the regular ubiquinone and it’s in capsules. None of those characteristics are ideal.

Dr. Harvey’s CoQ10 softgels are bright red and actually look a lot like Qunol MegaRed. It’s nice that they are a higher dose of 30 mg each, yet again it’s the drawback of something you need to shove down your pet’s throat daily, if not multiple times per day. Not nice to do!

The best CoQ10 for dogs and cats will be liquid forms without xylitol, as well as flavored chewables. These will be the most comfortable for them to take and if they’re beef or meat flavored, they actually taste like a treat. Whether liquid or chewable, if they’re made with water-soluble CoQ10 or ubiquinol, their absorption will be superior.

DogVites sells 30 mg beef flavored chewables. The only drawback with those is that they are the normal ubiquinone form. Still though, that makes DogVites a better option than VetriScience or Dr. Harvey’s in our opinion.

pet CoQ10

Our preferred choice is Stay-Well liquid CoQ10 for pets, which uses the water soluble form of ubiquinone. It comes in a dropper, which you can squeeze in their mouth, or mix with their water/liquid drink. The dropper shows you how much to measure, anywhere from 25 to 100 mg, with suggestions for each based on breed size. That feature is a favorite in reviews. You can buy Stay-Well on Amazon.

Another good option is Dr. Mercola ubiquinol for dogs. It’s liquid too and the dosage is 10 mg per pump. The packaging recommends that 10 mg for cats and toy dog breeds. For larger you will have to use more pumps. The Dr. Mercola label recommends 80 mg (8 pumps) for “giant” breeds of 80+ lbs. You can also get this product on Amazon.

Whichever product you choose, even if it’s the basic ubiquinone DogVites or a gel cap like VetriScience and Dr. Harvey’s, they may not be ideal but one could argue they are better than nothing at all. We would agree with that. Especially if your pet has congestive heart failure or another cardiac disease.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.