Essential Vitamins for Dogs and What They Do
Vitamins are needed in tiny amounts, but they play huge roles in a dog's health. Understanding what they do helps you judge diets and avoid unnecessary supplements. The good news is that a complete commercial diet generally has them covered.
Fat-soluble vitamins
These dissolve in fat and are stored in the body, so excess can build up and cause toxicity.
- Vitamin A. Supports vision, skin, growth and immunity. Sources include liver, fish oil and eggs. Too much can cause bone and liver problems.
- Vitamin D. Helps absorb calcium and phosphorus for bones. Dogs get it from food, not sunlight. Excess is dangerous, and some rodent poisons contain vitamin D compounds.
- Vitamin E. An antioxidant that protects cell membranes. Found in plant oils and organ meats.
- Vitamin K. Needed for blood clotting. Produced partly by gut bacteria and found in leafy greens and liver. Some rat poisons block it, causing bleeding.
Water-soluble vitamins
These are not stored in large amounts, so dogs need a regular supply.
- Thiamine (B1). Supports energy metabolism and nerve function.
- Riboflavin (B2). Helps release energy from food.
- Niacin (B3). Supports skin and digestion.
- Pantothenic acid (B5). Involved in energy production.
- Pyridoxine (B6). Needed for protein metabolism and nerve function.
- Folate (B9). Supports cell division and blood formation.
- Cobalamin (B12). Needed for nerves and red blood cells. Found in animal products.
- Biotin. Supports skin and coat.
- Choline. Important for brain and liver function.
Vitamin C
Dogs make their own vitamin C in the liver, so it is not considered essential. Some owners give it for specific reasons, but there is little evidence for routine supplementation. Large doses can cause stomach upset.
Where dogs get vitamins
Complete and balanced commercial diets include vitamin premixes to meet recognized standards. See our guide to AAFCO and FEDIAF standards. Fresh foods like liver, eggs, fish and vegetables also contribute, but they are not a substitute for a balanced recipe.
Deficiency
True deficiencies are uncommon on complete diets. They can happen with:
- Homemade diets that are unbalanced. See home-cooked dog food.
- Long-term feeding of unbalanced or incomplete foods.
- Digestive diseases that impair absorption.
Signs vary but may include poor coat, weight loss, weakness, poor growth, anemia and neurological problems. Contact your vet if you see them.
Too much of a good thing
Supplements can cause harm. Vitamin A and D toxicity are well documented, and adding supplements on top of a complete diet may push levels too high. Human multivitamins can contain dangerous ingredients such as xylitol or iron, which are toxic to dogs. See our guide to xylitol toxicity.
When supplements make sense
- When your vet diagnoses a deficiency.
- When feeding a homemade diet that requires a complete supplement.
- For specific health conditions, under guidance.
- For omega-3 fatty acids, in some dogs. See fish oil for dogs.
Vitamins and special life stages
Puppies, pregnant dogs and seniors have different vitamin needs, but complete life-stage diets are designed to cover them. Pregnant and nursing dogs need more of several nutrients, and are better served by a diet made for reproduction than by random supplements. Senior dogs may benefit from antioxidants such as vitamin E, which some senior formulas include. If you are considering a supplement for any life stage, bring the product to your vet so the total intake from food and supplements can be checked.
The takeaway
A complete and balanced diet usually supplies all the vitamins a dog needs. Avoid unneeded supplements, and talk to your vet if you suspect a problem. For minerals, see our guide to essential minerals for dogs.
Frequently asked questions
Do dogs need vitamin supplements?
Most dogs eating a complete and balanced diet do not need them, and extra can be harmful.
Can dogs make their own vitamin C?
Yes. Unlike humans, dogs make vitamin C in the liver, so it is not a dietary requirement for healthy dogs.
Is vitamin D safe for dogs?
It is essential but toxic in excess, so do not give human supplements without veterinary advice.
What are signs of vitamin deficiency?
They vary, but can include poor coat, weakness, poor growth, eye or nerve problems and anemia.
This article is general educational information, not veterinary advice. Every dog is different. If your dog is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.