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Human giving a Shiba Inu a vitamin with the paw on the human - What Human Vitamins Can I Give My Dog

What Human Vitamins Can I Give My Dog?

You'd do anything for your fur baby, right? We get it! You want them to live their best, tail-wagging life. 

So when you pop your daily vitamins, you might wonder, "Should I share the love with my pup?" and "Should I give my dog vitamins everyday?".

While vitamins are essential for both humans and dogs, our furry family members have their own unique needs. So what human vitamins are good for dogs? In most cases, it’s not safe to give vitamins and supplements made for people to your dog and there aren't any good human ones for them. Not only are they usually less effective, but the dosage, formulation, or ingredients could even be toxic. 

Can human vitamins kill dogs? Yes! So let’s take a look at some common ingredients in human multivitamins and find out which ones should never be shared.

What Are Vitamins?

Vitamins are essential organic nutrients that dogs obtain through the foods they eat. These nutrients play a critical role in many body functions and support everything from a healthy immune system to strong bones and a shiny coat.

Dogs require the same vitamins that we do (except for vitamin C, which they make themselves!). The following are considered essential vitamins for dogs:

  • Vitamin A (retinol)
  • Vitamin D (cholecalciferol)
  • Vitamin E (tocopherol)
  • Vitamin K (phylloquinone - more important for cats)
  • Thiamine (Vitamin B1)
  • Riboflavin (Vitamin B2)
  • Niacin (Vitamin B3)
  • Pantothenic Acid (Vitamin B5)
  • Pyridoxine (Vitamin B6)
  • Folic Acid/Folate (Vitamin B9)
  • Vitamin B12 (Cobalamin)
  • Choline

But here's the catch: the amount and type of each vitamin needed is totally different from the amount that YOU need. For this reason, human vitamins can be toxic to dogs, and giving vitamins to your dog can have harmful — or even fatal — consequences.

Here’s another fact you should know about vitamins: they’re classified as either fat-soluble vitamins (A, D, E, and K)  and water-soluble (C and B vitamins).

Fat-soluble vitamins dissolve in fat and are stored in the body's fatty tissues and liver. This means they don't need to be consumed as frequently. It also means they can accumulate to toxic levels if over-supplemented.

Water-soluble vitamins, on the other hand, dissolve in water and are not stored in the body to a significant extent. Excess amounts are typically excreted through urine, making toxicity less of a concern.

Last, just a few more terms you should be familiar with to understand your dog’s nutritional needs:

  • Minerals are inorganic elements that also play vital roles in your dog's health. They are involved in bone development, nerve function, and fluid balance, among other things. Minerals, like vitamins, are primarily obtained through food.
  • Nutrients are substances that provide nourishment essential for the growth, development, and maintenance of life. They are the key building blocks that fuel your dog's body! The six major categories of nutrients that dogs need are water, proteins, fats, carbohydrates, vitamins, and minerals.
  • Supplements are products designed to provide additional nutrients, including vitamins and minerals, that may be lacking in your dog's diet. They can come in various forms, such as chewable tablets, powders, or liquids.

For more information on your dog’s nutritional needs, see this in-depth guide by the National Resource Council.

Dog looking at a vitamin pill
Are vitamins necessary for dogs?

Are Vitamins Necessary For Dogs?

As long as you are feeding your dog a commercial food that is AAFCO-certified or WSAVA-compliant and appropriate for their lifestage, it will be complete and balanced to contain all the vitamins, nutrients, and minerals that they need.

In some cases, or as a treatment for certain medical conditions, your vet may recommend giving your dog additional supplements. Always use a formula made for pets and discuss the correct dosing with your veterinarian first.

What vitamins can I give my dog?

Here are some potentially safe vitamins for dogs and some details on each one to help you better understand them.

​​Vitamin C

This juicy water-soluble vitamin is generally safe for dogs in moderate amounts. Excess vitamin C is usually excreted in the urine, so the risk of overdose is low.

Although dogs can make their own vitamin C, some studies suggest that antioxidant properties in this vitamin may be useful in managing certain types of cancer, Tylenlol toxicity, and arthritis.

Dogs who are stressed, sick, senior, pregnant, or nursing may also have higher needs for vitamin C. If you are concerned that your dog may be lacking in vitamin C, ask your vet for their guidance and dosing recommendations.

Fun fact: While most animals are able to synthesize their own vitamin C, some can’t! That list includes humans (alas), guinea pigs, fruit-eating bats, and some types of fish, birds, and primates.

B Vitamins (B-complex)

Most B vitamins are safe for dogs in moderation. They play various roles in metabolism, energy production, and have essential roles in brain health, nervous system function, and production of red blood cells.

Any dog with chronic intestinal issues is at risk for B-12 deficiency and should be evaluated for such. B-12 supplementation by mouth or injection can be an important part of their treatment. However, as with any vitamin, excessive amounts can cause issues — so always follow your vet's guidance.

Fish Oil (Omega-3s)

Not technically a vitamin, omega-3s (EPA and DHA) are actually what’s known as “essential fatty acids”. The omega-3 fatty acids found in fish oil can be beneficial for your dog's skin, coat, and joint health.

These potent anti-inflammatories are also key for heart health, a strong immune system, and cognitive function. Fish oil is a common supplement given to dogs with allergies, dry, itchy skin, and arthritis. As always, ask your vet for dosage recommendations.

One last note on safety...

Even “safe” vitamins can be harmful if given in excess. Always consult your veterinarian for guidance on the appropriate type and amount of any supplement for your dog.

For safety and efficacy, it is best to use a product specifically formulated for animals, like Paramount Pet Health's Liquid Vitamins for Dogs.

Open hand with six vitamin pills in it

Human vitamins & minerals that are dangerous for dogs

Vitamin A

Vitamin A is essential for vision, growth, skin health, and reproduction. However, dogs process vitamin A differently than humans and have a lower tolerance for excess vitamin A — since it’s a fat-soluble vitamin that can quickly accumulate in their bodies.

In most species, the amount of vitamin A needed to cause toxic effects is approximately 10–1,000 times the dietary requirements. Vitamin A toxicity has been reported in dogs after consuming large amounts of fish oil, cod liver oil, or liver, over time.

Toxicity is also possible from ingestion of a single large dose of vitamin A (for example, ingesting a bottle of supplements at once).

Excess vitamin A can lead to a condition called hypervitaminosis A, causing a cascade of health problems. Symptoms can range from relatively mild issues like dry, peeling skin and hair loss to severe problems, including general malaise, anorexia, nausea, weakness, excessive bone growth, joint pain, tremors, seizures, paralysis, liver damage, and even death.

Note: Cats are more susceptible to vitamin A toxicity than dogs.

Vitamin D

Vitamin D is the "sunshine vitamin"! It's crucial for calcium absorption, bone health, and immune function. Yet this essential vitamin can be highly toxic to dogs if too much is ingested.

There are two forms of vitamin D: ergocalciferol (D2) and cholecalciferol (D3). Cholecalciferol (contained in many supplements as well as a key ingredient in certain types of rodenticide) poses the most significant threat due to its high toxicity. Clinical signs of cholecalciferol toxicity have been seen with doses as low as 0.5 mg/kg.

Vitamin D toxicity can result from dogs ingesting:

  • Human supplements
  • An overdose of canine supplements
  • Rodenticides
  • Plants, fungi, and yeast
  • Unbalanced home-cooked diets
  • Or other medications (such as some psoriasis creams)

In just 12 hours after ingesting a significant dose of vitamin D, dogs may exhibit symptoms like vomiting, diarrhea, loss of appetite, abdominal pain, depression, increased thirst and urination, and elevated phosphate levels.

These initial symptoms often escalate within 24-48 hours, leading to hypercalcemia (a dangerous buildup of calcium in the blood) and acute kidney failure.

Other severe signs of toxicity may include difficulty breathing, irregular heartbeat, internal bleeding, mineralization of tissues (such as the heart, gastrointestinal tract, and even the kidneys themselves), and death.

As with all cases of poisoning, timely veterinary intervention is crucial if you suspect your dog has consumed a toxic amount of vitamin D.


While not a vitamin, iron is a mineral essential for oxygen transport and energy production. Commonly found in human multivitamins and various household items (such as hand warmers and fertilizers), iron poses a significant risk of poisoning for dogs.

Iron toxicity occurs when a dog consumes a large amount of iron, overwhelming the body's ability to regulate its iron levels. While iron is necessary for various bodily functions, excessive amounts can wreak havoc on the gastrointestinal system, liver, and nervous system. 

The severity of iron poisoning depends on the amount ingested and the dog's size, with 20 mg/kg and above considered a toxic dose. There are four stages of iron poisoning:

  • Stage 1: Within the first six hours of ingestion, initial signs such as lack of appetite, vomiting, diarrhea (potentially bloody), abdominal discomfort, and lethargy may be seen.
  • Stage 2: Symptoms may temporarily improve, creating a false sense of security.
  • Stage 3: Within 12 to 36 hours of ingestion, symptoms return with a vengeance. The dog may experience shock, a rapid heart rate, cardiovascular collapse, tremors, and jaundice (yellowing of the eyes, ears, and gums). In the most severe cases, death can occur during this stage.
  • Stage 4: Even if the dog survives the initial onslaught, effects may emerge again 4-6 weeks later. Internal bleeding, organ damage (especially to the liver and kidneys), and intestinal blockages (as a result of strictures in the intestines) can occur.

The main mechanism behind iron toxicity involves the generation of harmful free radicals that damage cells and tissues. Prompt veterinary treatment with decontamination, chelation therapy (to bind and remove excess iron), and supportive care can significantly improve the chances of recovery. So the answer is no to the question we get asked, 'Can I give my dog human iron supplements'.

If you believe your dog has ingested an overdose of vitamins or minerals, call your veterinarian or a 24/7 animal poison control center right away.

Golden Retriever laying down looking sad

Other Hidden Dangers in Vitamins and Supplements

Xylitol (AKA birch sugar, birch sap, and more names — see below)

Xylitol is a sugar substitute commonly found in sugar-free gum, candies, baked goods, and potentially in flavored supplements. More recently, it’s begun being listed on ingredient labels with a variety of other names, including:

  • Birch sugar
  • Birch sap
  • Sucre de bouleau (in French-speaking areas)
  • Mes-xylitol
  • Xlitol
  • Xylite
  • E967 (in Europe)
  • Xylo-pentane-1,2,3,4,5

Regardless of its name, this substance poses a grave danger to our canine companions. While harmless to humans, even small amounts of xylitol can be fatal for dogs.

The culprit behind this alarming toxicity lies in the way dogs process this sugar alcohol.

In dogs, xylitol triggers a massive release of insulin, leading to a rapid and severe drop in blood sugar levels, known as hypoglycemia. This sudden plunge can occur within minutes of ingestion, causing weakness, lethargy, seizures, and even liver failure.

Recognizing the signs of xylitol poisoning and seeking immediate veterinary care is crucial to saving a dog's life. 

Remember, xylitol is a hidden danger lurking in many everyday products, including some types of peanut butter, chewing gum, and lip balm.

Even a small piece of gum containing xylitol can be fatal to a dog — so always keep these items out of reach and opt for pet-safe treats or products.

Paramount Pet Health Liquid Vitamins for Dogs

Human Multivitamins

Can you give dogs human multivitamins? Even vitamins safe in small amounts can be dangerous in the high concentrations found in many human multivitamins.

Additionally, multivitamins and other supplements may contain other ingredients that are unsafe for dogs, such as xylitol. For these reasons, human multivitamins should never be given to dogs. 

The bottom line is simple: human vitamins and supplements are not intended for dogs and can pose serious health risks. While we need many of the same nutrients, our furry best friends have unique dietary requirements. Giving them human vitamins can lead to imbalances, toxicities, and even life-threatening conditions.

Always consult your veterinarian before giving your dog any vitamins or supplements. They can assess your dog's individual needs and recommend safe and effective options specifically formulated for canines.

So share the love, but keep the human supplements for yourself…because your dog's health is too precious to risk with well-intentioned but potentially harmful human products! And there are some great vitamins for dogs out there!

Next article What Can I Add to My Dog's Kibble Every Day?

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