You know those multi-vitamins you take every morning (or should take every morning)? Can’t you just slide one of those to your pooch once a day and skip the hassle of researching and buying specialized pet supplements? It’s easy—but it’s rarely a good idea. We floated this thought to a community of experienced pet owners, veterinarians, and wellness specialists. Here’s what they had to say on the topic:

Dr. Jim D. Carlson

Dr. Jim D. Carlson

Holistic Veterinarian

Jim D. Carlson, DVM CVA CVTP, owner and holistic veterinarian at Riverside Animal Clinic & Holistic Center of McHenry, Illinois.

Human vitamins are not dog vitamins and should not be used as a replacement unless recommended by your veterinarian with a specific quantity and duration. Since dog foods contain all of the essential daily requirements, most dog vitamins only contain about 20 percent of the daily requirement to avoid overdosing your dog. Human vitamins will provide 100 percent of the daily requirement, so if your dog is eating its dog food and taking a human vitamin, it will be receiving more than the daily recommended amount of vitamins and supplements.

Prenatal vitamins can be especially toxic because of the levels of iron contained in the product and may create iron toxicity which can be dangerous to your dog. Signs of iron toxicity include: vomiting, diarrhea, bloody diarrhea, lethargy, and shock among others. Other vitamins that are potentially toxic are vitamins D and B, which could have similar symptoms to iron toxicity.

Accidental ingestion is the most common cause of vitamin toxicity but prolonged over-supplementing is just as problematic to the unknowing pet owner and is often overlooked when considering reasons for their pet’s sickness with their veterinarian.

Proper storage of vitamins is important in the home. Some human vitamins are chewy and gummy and smell great so a pet is attracted to the bottle. With more vitamins and supplements being sold in a candy-like form, there is a chance that pets will be more attracted to their fun shape and texture. Remember to put away your vitamins, pick up any pills or gummies that fall on the floor and keep bottles in upper cabinets.

When choosing vitamins for your dog, consult with your veterinarian and then choose only those supplements approved by your veterinarian or the National Animal Supplement Council, which provides a seal of approval on the product label. Only use the vitamins for a recommended period of time and for specific reasons to avoid overdosing and creating health problems.

There are several issues with giving dogs human vitamin supplements. The biggest problem is one of vitamin D. Dogs require vitamin D, or D3, cholecalciferol, because they don’t make their own in their skin from the sun like humans do. There has not been a lot of research on vitamin D requirements for dogs. We know that not enough of it is bad and too much of it is worse.

Although dogs require vitamin D, too much vitamin D is toxic for dogs, and most human multivitamins have too much. The current recommendation for dogs is 500IU per kilo of food. The lowest amount of vitamin D in a multivitamin commonly available for humans is 400IU in a very few children’s vitamins.

Vitamin D is fat soluble. That means that it’s stored in the body, and an overdose is not readily excreted and not easy to treat. Furthermore, the amount of vitamin D required varies by the dog’s A) sex, B) age, C) activity level, and D) breed. Arctic working dogs, for example, require more than a French Bulldog whose chief activity is snoring.

If you’re feeding your dog a quality dog food, then the dog is likely getting enough vitamin D. If you’re making homemade food, then the dog is likely not getting enough without supplementation. However, if you’re making homemade food, there’s a good chance the food is also lacking in the amino acid, taurine, required by dogs.

So, the only reason to supplement would be if you are not buying commercially prepared food. And if you’re making your own food, then you need to worry about more than just vitamin D. You need to worry about the ratio of calcium to phosphorus and a long list of other vitamins and minerals not necessarily in the correct ratios for dogs.

A child’s multivitamin with vitamin D not exceeding 400IU is a good temporary solution while you investigate a better one with a licensed veterinary nutritionist. If you’re going to make homemade dog food, then be sure to buy an accurate and precise laboratory-grade scale for measuring supplements. This kind of scale will easily cost north of $200.

You will have no choice and have to use some human vitamin supplements to fill out the nutritional requirements for the dog, because if you are measuring and adding the vitamins one by one, you won’t be able to buy them all marketed just for dogs. It will also be cheaper to buy the human versions in some cases, but now we’re not talking about multivitamins—we’re talking about individual vitamins and minerals such as iron, magnesium, vitamin E and so forth. In this case, the human versions will often be all there is to choose from.

Cynthia White

Cynthia White

Cynthia White is a long-form business writer and editor with more than 20 years of experience and a BA in English. She has been a stockbroker, a physician’s assistant, and was a marketing executive for 15 years. She has three special-needs bulldogs and is very active in bulldog rescue.

Dr. Jennifer Coates

Dr. Jennifer Coates

Dr. Jennifer Coates was valedictorian of her graduating class at the VA-MD Regional College of Veterinary Medicine and has practiced in Virginia, Wyoming, and Colorado.

Dogs can take some human vitamin supplements but others can be quite dangerous due to physiological and dosing differences between people and dogs. It’s very important to talk to your veterinarian before giving any pet a new vitamin supplement. As long as your dog is healthy and eating a nutritionally complete and balanced, life-stage appropriate commercial pet food that conforms to AAFCO (Association of American Feed Control Officials) standards, vitamin supplementation should not be necessary.

Adding extra vitamins may result in the development of toxicities. If you feed your dog a home-prepared food, vitamin supplements are necessary, but the amounts and types need to be determined based on the other ingredients included in the diet. Work closely with your veterinarian or a veterinary nutritionist if you feed a home-prepared diet to your dog. Pets with specific health problems may benefit from a vitamin supplement (vitamin K for certain forms of rodenticide poisoning, for example), but a veterinarian familiar with the specifics of the case will need to prescribe the correct product and dose.

Most pet foods contain enough nutrients that ensure your dog won’t need a multivitamin in the first place. With this in mind, the concentration of human vitamin supplements contains the daily requirement for humans, not for dogs. Especially if they’re already meeting requirements naturally in their diet, you might be ‘nourishing ‘ them with more than their body can handle. That being said, some supplements may be beneficial for your dog but it’s always best to run it past a vet before taking matters into your own hands.

Nate Masterson

Nate Masterson

Nate Masterson is a certified health expert and head of natural product development for Maple Holistics, a company dedicated to cruelty-free and sustainable personal care products.


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