Multi-vitamins and other complementary nutritional products have become hugely popular for us humans, but should you give your dog supplements? This article will answer your most commonly asked questions and discuss some of the common conditions for which supplements may be beneficial for dogs.

Does your dog need vitamin supplements?

In most cases, vitamin supplements are not essential for your dog’s health and wellbeing. Healthy dogs that are fed a high-quality complete and balanced diet are already getting everything they need nutritionally from their food. This includes vitamins and minerals.

To ensure you’re choosing a quality pet food, make sure it is from a reputable company and is appropriate for your dog’s life stage, breed, and size. Growing puppies need more protein and energy than adult dogs. Large breed puppies, in particular, need the right balance of calcium and phosphorus for healthy growth and development.

This is where using supplements, such as additional calcium, can even be harmful as you risk unbalancing the diet, which may lead to abnormal bone growth and severe orthopedic issues later in life.


Do dogs on a homemade diet need vitamins?

The exception to this rule is for dogs that are fed a homemade diet. Studies have shown that most of these diets are deficient in at least one essential nutrient, and usually require supplementation to make them complete and balanced, like a more traditional commercial dog food. If you are considering feeding your dog a home-cooked diet, always make sure it has been expertly formulated by a qualified veterinary nutritionist.

What about dogs with medical problems?

Finally, there are uncommon medical conditions such as zinc-responsive dermatosis, a skin condition in dogs, that is treated with a specific nutritional supplement (in this case, zinc!). However, these diseases must be diagnosed by your veterinarian before an appropriate dose and formulation are prescribed.

Giving a supplement if there is no evidence of deficiency can risk giving your pup a toxic overdose of certain vitamins and minerals!

Other diseases such as arthritis (osteoarthritis) may also benefit from supplements like glucosamine and chondroitin, but it’s important to remember that clinical trials and studies to support their effectiveness are still in the early stages.

Regardless of the reason you’re considering giving supplements to your dog, you need to seek advice from your veterinarian first. As previously discussed, when used incorrectly nutritional supplements may cause harm and can even interact with medications or worsen certain medical conditions.

Nutrient requirements in dogs


Six basic nutrients are required for all bodily functions in dogs. These are water, proteins, fats, carbohydrates, vitamins, and minerals. 

Nutrition is a complex topic, and the details are well beyond the scope of this article. However, all pet foods labeled as a ‘complete and balanced’ diet according to AAFCO (the Association of American Feed Control Officials) guidelines must contain the minimum levels of essential nutrients required by dogs. The complete list and their recommended minimum levels in a balanced food for dogs can be found here.

When should you use vitamin supplements for your dog?

As mentioned previously, vitamin supplements should only ever be given to dogs after a discussion with your veterinarian and if there is a clear need or possible benefit. They will be able to recommend an appropriate dose and formulation uniquely for your pet. Many human supplements do not meet these criteria and even amongst those supplements available for dogs, the quality can vary substantially.

Conditions that may benefit from the use of nutritional supplements include:



Osteoarthritis (also known as arthritis) is a degenerative disease that affects the joints and causes painful changes over time such as destruction of healthy cartilage, thickening, inflammation, and reduced mobility.

There is no cure for osteoarthritis, however, supplements such as glucosamine, chondroitin, and omega-3 and 6 fatty acids may be beneficial to help reduce inflammation, and improve mobility.

Skin allergies

Some forms of allergic skin disease, such as atopic dermatitis, may also benefit from supplementation with omega-3 and 6 fatty acids, due to their anti-inflammatory effects.

Atopic dermatitis (atopy) is an allergic skin disease where the body produces an abnormal immune system response to common allergic triggers (allergens) such as grass, pollens, and dust mites. In some cases, a veterinary dermatologist may also recommend supplementation with vitamin E and/or zinc.


Certain supplements have been linked to an improvement in behavior relating to anxiety or stress in dogs. These include tryptophan, which helps produce serotonin, a key neurotransmitter for mood stabilization, and alpha-casozepine (originating from milk protein) which has a calming effect on the brain. Some pet foods designed for calming also contain these ingredients.

The natural bacteria that reside within the gut (microbiome) is also believed to impact mental health and wellbeing in humans and this interaction is suspected to be similar in dogs.

Studies are in the early stages, but probiotics (‘good’ gut bacteria) may have a role to play as we begin to understand more about the bacterial species that live within the gut and their complex interactions.



Speaking of probiotics, most of the current evidence for their use in dogs is for short-term cases of diarrhea (such as from an upset tummy or virus). They may also be useful for inflammatory bowel disease (IBD) or other types of gastrointestinal disease

When it comes to probiotics, strain matters, and there is still a lot of work to be done to identify which strains of good bacteria are most effective for dogs. More information about probiotics can be found here.

Cases of diagnosed nutrient deficiencies

Various diseases result from a deficiency in a particular essential nutrient or its building blocks. This can be through an inadequate or unbalanced diet or due to diseases that interfere with absorption or metabolism. For example, zinc-responsive dermatosis an uncommon skin disease caused by poor absorption of zinc.

Unless your dog has been diagnosed with a nutritional deficiency by a veterinarian, supplementing zinc or any other essential vitamins or minerals can risk causing a toxic overdose.


Healthy dogs that are fed a complete and balanced, high-quality dog food do not require any additional supplements unless specifically advised by a veterinarian. Their food is already perfectly balanced to meet their needs.

Dogs that are fed a home-cooked diet, however, should consult a specialist veterinary nutritionist for a balanced recipe (with supplements) as deficiencies are extremely common in these diets.

Certain medical conditions may benefit from the use of nutritional supplements including osteoarthritis, anxiety, and allergic skin disease. However, clinical research is still in the early phases and you should always discuss the use of any supplement with your veterinarian first.