Vitamin D for Dogs: Dosage and Side Effects

Vitamin D for Dogs: Dosage and Side Effects

Vitamin D is an essential and fundamental vitamin for many body functions, including calcium phosphate balance between bones, kidneys and parathyroid gland, bone mineralization, immune cell differentiation, insulin secretion, the formation of blood cells, etc.

For dogs to have their dose of vitamin D, they must be fed with a specific food for the canine species. Indeed, a food made for dogs contains the necessary doses of vitamin D so that your best friend absorbs the right amount (not too much, not enough). In excess, this vitamin is not good because it accumulates in the liver and it cannot be eliminated through the urine because of its fat solubility and not its water solubility. If you want to know more about the vitamin D for dogs, its dosage, its benefits and its contraindicationswe invite you to continue reading this article from PlanèteAnimal!

What is Vitamin D?

Vitamin D is an essential nutrient to regulate the balance and assimilation of phosphorus and calcium. As it is a fat-soluble but not water-soluble vitamin, if a dog ingests more vitamin D than necessary, it accumulates in the body (liver and fatty tissue) and cannot be eliminated in the urine. This excess of vitamin D can be dangerous for the dog because it can induce kidney failure or death.

In humans and other species, the synthesis of vitamin D begins with exposure to sunlight through the skin, which converts 7-dehydrocholesterol into provitamin D3, but the dog cannot synthesize enough of it, perhaps due to increased activity of 7-dehydrocholesterol-Δ7-reductase.

Therefore, for a dog to get enough vitamin D, they must consume it through their diet; which can be either animal (cholecalciferol or vitamin D3) or vegetable (ergocalciferol or vitamin D2).

What is vitamin D for dogs?

What is the effect of vitamin D on the body of dogs? Vitamin D in dogs has many functions, including homeostasis or the balance between calcium and phosphorus across the axis established between the bonesthe parathyroid gland and the kidney, promoting its reabsorption and preventing losses.

Vitamin D also participates in the remodeling and mineralization of bones, their formation and the development of the skeleton. It also acts on the cells of the small intestine by promoting the absorption of calcium and phosphorus which will then pass into the bones.

This vitamin is also involved in the differentiation of immune system cells as it promotes the passage from monocytes to macrophages, hematopoiesis, insulin secretion, reduction of proteinuria and inflammation.

Therefore, if your dog does not have enough vitamin D and you are not sure if he needs more or not, you should know that in case of vitamin D deficiency, the bones tend to break down. demineralize, shrivel up and weaken and may develop irreversible malformations, such as rickets in puppies and osteomalacia in adults.

Dose of vitamin D in dogs

Dogs need a minimum daily dose of 227 IU per kilogram of dry food for the canine species. Doses above 2700 IU/kg body weight are toxic.

Although much less than in other species, dogs can also convert vitamin D in the most superficial layers of the skin, but the consumption of dry foods or human foods rich in vitamin D will cover their needs, preventing thus any deficiency.

Once absorbed, vitamin D passes through the lymphatic system and carries the system to the liver, a process that requires the activation of chylomicrons, digestive enzymes, bile acids, transcalciferins, and vitamin D-binding proteins.

Vitamin D for dogs: Dosage and side effects - Dosage of vitamin D in dogs

How do I give vitamin D to my dog?

A dog that has a correct diet based on kibble consumption should not have a vitamin D deficiency problem.

However, if a dog does not follow a correct diet or if they eat too many vegetables, perhaps because of the vegetarian or vegan habits of their guardians, they are likely to develop a vitamin D deficiency, because plants must be dried in the sun to obtain vitamin D. Therefore, a dog that eats only vegetables will need to consume vitamin supplements.

Foods intended for humans, such as as egg yolk, butter, kidneys, fatty fish and cod liver oilare also sources of vitamin D for dogs.

Vitamin D for dogs: Dosage and side effects - How do I give vitamin D to my dog?

Side Effects of Vitamin D on Dogs

When guardians give their dogs vitamin D supplements or, worse, a supplement intended for human consumption in much higher doses than a dog needs, overvitaminosis or vitamin D toxicity in dogs can occur. It manifests itself through the following clinical symptoms:

  • Vomiting
  • Weak appetite
  • Weightloss
  • Increased need to drink and urinate
  • Hypersalivation

In effect, vitamin D accumulates in the dog’s liver and fatty tissuewhich is unable to eliminate excess vitamin D through urine.

Contraindications of vitamin D in dogs

The main contraindication to the use of vitamin D in dogs is to give them vitamin D supplements while their kibble provides them with the dose they need. In effect, excess vitamin D is toxic to dogs and accumulates in their body tissuescausing the severe symptoms described above.

This is because excess vitamin D is toxic to dogs and accumulates in their tissues, causing the severe symptoms described above.

If you want to read more articles like Vitamin D for Dogs: Dosage and Side Effectswe recommend that you consult the Balanced Diets section.


  1. Aveaca. Nutritional requirements for perros and cats. Available at:ón-Sección-02.pdf


  • R. Elices. (2010). Atlas de nutrición y alimentación práctica en perros y gatos. Servet.

Vitamin D for Dogs: Dosage and Side Effects

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