What was it that Ralph Waldo Emerson said? “Moderation in all things, especially moderation.” Witty as always, Mr. Emerson, but in there lies a truth: moderation is key—even when you need to moderate your moderation.

Healthy habits can become unhealthy habits when taken to the extreme. Running is great for your body. Running nonstop from the moment you wake up to the moment you crash and burn is great… for injuries. Cake is good for the soul. Marie-Antoinette even said, “Let them eat cake!” Alas, even cake, in excess is not good.

The same philosophy applies to your dog’s supplementation; they’re great for health… in moderation. 

When Too Much is Too Much

It’s strange to think that offering vitamins and minerals can have negative downsides. Sure, the cake example made sense. But what if you’re offering your dog a multivitamin, something that’s supposed to be made of pure, healthy ingredients? Unfortunately, even the healthiest of nutrients must be fed in moderation.

To offer some examples of why, here are some vitamins with their benefits and their downsides:

  • Vitamin A – The first thing you’ll notice if your dog has a vitamin A deficiency is their skin and coat start to decline. First, it will be dry skin, then clumps of hair might shed off randomly. Continued deficiency and your dog may suffer from muscle deterioration and night blindness. Vitamin A protects against all of these, which may make you want to supplement.
  • Too much vitamin A – Vitamin A toxicity takes time to develop (sometimes months), which makes supplementation particularly difficult. The main symptom is stiffness. The increased amount of vitamin A in the system causes new bone to grow around joints, sometimes making it hard for your dog to move its neck entirely.
  • Vitamin D – Vitamin D is great for the retention of calcium and phosphorus. This makes it a core building block in the development of healthy bones and the skeletal structure.
  • Too much vitamin D – While great in small doses, supplementing too much vitamin D can cause kidney failure and even death.
  • Glucosamine and Chondroitin – If you’ve been in the dog supplement world for even fifteen minutes, you’ve probably read something about this duo. Glucosamine and chondroitin have been wildly popular for proper joint health, and they’ve been said to help elderly dogs regain their youthful swing. But is Glucosamine really trustworthy?
  • Too much glucosamine and chondroitin – When supplements don’t perform magically, many owners think it’s because the dosage is too low. Unfortunately, too much joint supplementation can cause multiorgan dysfunction syndrome. Glucosamine has also been reported as a top poison for dogs in recent years due to the potential for overdosing. 

While there are more vitamins and minerals to add to this list, let’s go from specifics to generalizations.

Fat-Soluble vs Water-Soluble

What do many of the above examples have in common? Most of these (and other supplements that can lead to toxicity) are known as fat-soluble nutrients. These work differently than, say, vitamin C, which is a water-soluble nutrient.

What’s the difference?

  • Fat-soluble vitamins – As the name suggests, fat-soluble vitamins can be absorbed through fatty tissue. They can be stored for long periods and build up over time. When taken in large doses all at once or built up over time, hypervitaminosis can occur, which is equivalent to a poison or toxin in the system.
  • Water-soluble vitamins – In a similar manner, water-soluble vitamins dissolve in water, thus they dissolve in your body. Because water isn’t stored long in your dog’s body, these types of nutrients can be taken in excess. If your dog “overdoses,” the vitamins just exit your dog’s system through their urine. 

If you’re curious whether your supplement contains fat-soluble or water-soluble vitamins, perform a quick online search. This will help you know when giving too much can be toxic.

When Does Supplementing Become Dangerous?

One supplement in your dog’s diet probably isn’t going to be enough to cause harm to your furry friend. It’s when owners provide one supplement for their eyes, one for their liver, one for their joints, and one for good measure, supplementation becomes dangerous.

That’s why it’s important to find a supplement that has everything your dog needs for bio-replenishment. Vetericyn offers the All-In supplement for exactly that reason. All-In offers dogs a supplement that is:

  • Age-specific – Puppies and senior dogs don’t need the same nutrients. Supplements should address the age of the dog to give them what they need when they need it.
  • Gut-friendly – Probiotics and prebiotics are necessary for a healthy gut biome. This biome is responsible for everything from the proper absorption of nutrients to your dog’s mood to their physical wellness.
  • Good for joint health – Puppies’ bones are rapidly growing; senior dogs’ bones are decaying. Both need vitamins and minerals targeting joint health to ensure a happy and healthy life.
  • Antioxidative – Antioxidants remove the free radicals from your dogs’ cells which slows down the aging process.

With a single supplement, you don’t have to worry about hypervitaminosis turning toxic. Moderation is built right in.


FDA. Vitamin D Toxicity in Dogs. https://www.fda.gov/animal-veterinary/animal-health-literacy/vitamin-d-toxicity-dogs

NCBI. Multiorgan dysfunction syndrome secondary to joint supplement overdosage in a dog. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4357907/


Dr. Melinda J. Mayfield-Davis, DVM, WCHP-AH, brings over 20 years of experience in veterinary medicine.  She is the Technical Services Veterinarian with Innovacyn, Inc., parent company of Vetericyn Animal Wellness. She received her DVM from Oklahoma State University and now resides in Southeast Kansas with her husband, two children, four dogs, and six horses. Prior to working with Innovacyn, Dr. Mayfield owned and operated the Animal Care Center in Columbus, KS.

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